Sacramento, Delevan, Colusa, and Sutter 

National Wildlife Refuges 

Draft Comprehensive Conservation Plan 

Prepared by: 

U.S. Fish and Wildlife Service 

Region 8 

Refuge Planning Office 

2800 Cottage Way, W-1832 

Sacramento, CA 95825 

and 

Sacramento National Wildlife Refuge Complex 

752 County Road 99W 

Willows, CA 95988 

July 2008 

Table of Contents 

Acronyms and Abbreviations................................................................vii

Chapter 1. Introduction and Background ............................................1

1. Introduction ..........................................................................................1

2. Purpose of and Need for Plan ............................................................3

3. Legal and Policy Guidance .................................................................3

3.1. National Wildlife Refuge System Improvement Act ..............3

3.2. Appropriate Use Policy ...............................................................4

3.3. Compatibility Policy.....................................................................5

3.4. Biological Integrity, Diversity and Environmental Health

Policy .....................................................................................................6

4. The U.S. Fish and Wildlife Service ...................................................6

5. The National Wildlife Refuge System ..............................................7

6. The Sacramento National Wildlife Refuge Complex......................8

7. Sacramento National Wildlife Refuge ............................................10

8. Delevan National Wildlife Refuge...................................................12

9. Colusa National Wildlife Refuge .....................................................13

10. Sutter National Wildlife Refuge ....................................................15

11. Refuge Purposes ..............................................................................16

11.1. Sacramento Refuge Purposes.................................................16

11.2. Delevan Refuge Purpose.........................................................17

11.3. Colusa Refuge Purposes..........................................................17

11.4. Sutter Refuge Purposes ..........................................................17

12. The Refuges’ Vision .........................................................................18

13. Existing and New Partnerships.....................................................18

14. Ecosystem Context..........................................................................19

15. Conservation Priorities and Initiatives.........................................22

16. Wilderness Review ..........................................................................23

Chapter 2. The Planning Process .........................................................25

1. Introduction ........................................................................................25

2. The Planning Process........................................................................25

3. Planning Hierarchy ...........................................................................26

4. The Planning Team............................................................................28

4.1. Core Team ...................................................................................28

4.2. Expanded Team..........................................................................29

5. Pre-Planning.......................................................................................29

6. Public Involvement in Planning.......................................................29

7. Public Outreach..................................................................................31

8. Issues, Concerns, and Opportunities ..............................................31

9. Development of the Refuge Vision ..................................................32

10. Determining the Refuge Goals, Objectives, and Strategies ......33

10.1. Goals ...........................................................................................33

10.2. Interim Refuge Goals...............................................................33

10.3. Objectives, Rationale, and Strategies....................................33

11. Development of the Refuge Management Alternatives.............35

11.1. Alternative A: No Action .........................................................35

11.2. Alternative B: Emphasize Biological Resources..................35

11.3. Alternative C: Proposed Action..............................................35

11.4. Alternative D: Emphasize Visitor Services ..........................36

12. Selection of the Proposed Action ...................................................36

13. Plan Implementation .......................................................................36

i 
Chapter 3. The Refuge Environment...................................................37

1. Refuge Descriptions..........................................................................37

1.1. Sacramento Refuge....................................................................37

1.2. Delevan Refuge ..........................................................................38

1.3. Colusa Refuge.............................................................................39

1.4. Sutter Refuge .............................................................................40

2. Geographic/Ecosystem Setting .......................................................41

2.1. The Sacramento Valley Ecosystem.........................................42

3. Physical Environment.......................................................................43

3.1. Climate and Air Quality ............................................................43

3.2. Water Supply..............................................................................45

3.3. Contaminants and Water Quality ............................................48

3.4. Geology, Hydrology, and Soils .................................................49

4. Habitat ................................................................................................51

4.1. Vegetation ...................................................................................51

4.2. Wetlands......................................................................................56

4.3. Grasslands...................................................................................61

4.4. Riparian Habitats.......................................................................61

4.5. Agricultural Croplands..............................................................62

5. Habitat Management ........................................................................63

5.1. Water Management ...................................................................65

5.2. Vegetation Management...........................................................68

5.3. Control of Invasive, Exotic, or Pest Species ..........................76

5.4. Mosquito Management..............................................................79

6. Fish and Wildlife................................................................................79

6.1. Waterfowl....................................................................................80

6.2. Breeding Waterfowl...................................................................86

6.3. Shorebirds...................................................................................86

6.4. Wading/diving birds...................................................................87

6.5. Gulls/terns ...................................................................................87

6.6. Birds of Prey...............................................................................88

6.7. Game birds ..................................................................................88

6.8. Other Landbirds.........................................................................89

6.9. Mammals .....................................................................................90

6.10. Amphibians and Reptiles ........................................................90

6.11. Fish.............................................................................................90

6.12. Invertebrates ............................................................................91

6.13. Threatened and Endangered Species ...................................92

7. Fish and Wildlife Management .....................................................103

7.1. Migratory Bird Management .................................................103

7.2. Threatened and Endangered Species Management...........105

7.3. Game Management ..................................................................106

7.4. Monitoring, Research, and Investigations ...........................106

7.5. Wildlife Disease Monitoring and Treatment........................107

8. Visitor Services ................................................................................111

8.1. Visitor Services and Management Policy .............................111

8.2. Trends........................................................................................112

8.3. Visitor Data...............................................................................115

8.4. Recreation Fee Program ........................................................117

8.5. Hunting......................................................................................118

8.6. Fishing.......................................................................................130

8.7. Wildlife Observation ................................................................131

ii 
8.8. Wildlife Photography ...............................................................132

8.9. Environmental Education .......................................................133

8.10. Interpretation and Outreach.................................................135

8.11. Non-wildlife dependent Recreation .....................................136

8.12. Youth Program .......................................................................136

8.13. Volunteer Program ................................................................137

9. Cooperation with Adjacent Landowners......................................137

10. Fire Prevention and Hazard Reduction .....................................137

11. Law Enforcement and Resource Protection..............................138

12. Facilities Maintenance ..................................................................139

13. Safety...............................................................................................139

14. Cultural Resources ........................................................................140

15. Social and Economic Environment .............................................143

15.1. Transportation ........................................................................143

15.2. Employment............................................................................144

15.3. Local Economy .......................................................................145

15.4. Land Use and Zoning.............................................................146

15.5. Demographics .........................................................................146

Chapter 4 Planned Refuge Management and Programs ..............149

Overview of Goals, Objectives, and Strategies ................................149

Organization..........................................................................................150

Refuge Management Goals, Objectives, and Strategies ................150

1. Wildlife and Habitat Goal...........................................................150

2. Threatened and Endangered Species Goal .............................165

3. Visitor Services Goal ...................................................................167

4. Partnerships Goal........................................................................181

5. Resource Protection Goal...........................................................183

Chapter 5. Management Plan Implementation ..............................187

1. Implementation ................................................................................187

2. Funding & Staffing..........................................................................187

3. Step-Down Management Plan Summaries ..................................194

3.1. Hunt Plan...................................................................................194

3.2. Visitor Services Plan ................................................................194

3.3. Habitat Management Plan......................................................195

3.4. Integrated Pest Management Plan........................................195

3.5. Resource Inventory and Monitoring Plan ............................195

3.6. Waterfowl Disease Contingency Plan ...................................196

3.7. Water Management Plan ........................................................196

3.8. Fire Management Plan............................................................196

4. Appropriate Use Requirements.....................................................197

5. Compatibility Determinations........................................................197

6. Compliance Requirements..............................................................198

7. Monitoring and Evaluation.............................................................198

8. Adaptive Management ....................................................................199

9. CCP Plan Amendment and Revision ............................................199

Glossary ....................................................................................................201

Bibliography ............................................................................................219

iii 
Figures 

Figure 1. Sacramento Refuge Complex Map. ........................................2

Figure 2. Ecosystem Map.......................................................................21

Figure 3. The CCP Process....................................................................26

Figure 4. Hierarchical relationship of refuge goals and objectives to 

other aspects of the planning process. ..................................................27

Figure 5. Relationships between Service and other planning efforts.

...................................................................................................................28

Figure 6. Sacramento Refuge Habitat Management Map. ................52

Figure 7. Delevan Refuge Habitat Management Map........................53

Figure 8. Colusa Refuge Habitat Management Map. .........................54

Figure 9. Sutter Refuge Habitat Management Map...........................55

Figure 10. California Mid-winter Indices (USFWS 1965-2007).........81

Figure 11. Sacramento Refuge Visitor Services Map. ......................168

Figure 12. Delevan Refuge Visitor Services Map..............................169

Figure 13. Colusa Refuge Visitor Services Map. ...............................170

Figure 14. Sutter Refuge Visitor Services Map.................................171

Figure 15. Sacramento Refuge Complex Staffing Plan. ...................192

Figure 16. Fire Staffing Plan. ..............................................................193

iv 
Tables 

Table 1. Public Scoping Meetings. .........................................................30

Table 2. Refuge Issues Identified Through Public Comment. ...........30

Table 3. CVPIA Water Supplies for each of the Refuges. ..................45

Table 4. Acreage and habitats of Sacramento National Refuge

Complex. ...................................................................................................51

Table 5. Approximate number of acre-feet/acre/month required for 

each wetland habitat type on the Complex. ..........................................66

Table 6. Invasive Plant Species at Sacramento Refuge Complex. .....77

Table 7. Regular waterfowl survey summary, early December, 2006.

...................................................................................................................83

Table 8. Average duck densities (per acre with sample size in 

parentheses) by habitat type on managed wetlands at Sacramento 

Refuge Complex.......................................................................................85

Table 9. Federal and State listed species occurring or potentially 

occurring at Sacramento, Delevan, Colusa, and Sutter Refuges. ......93

Table 10. Migratory bird surveys and other monitoring efforts

currently conducted by Sacramento Refuge Complex staff1

. ...........104

Table 11. Comparison of lead and steel shot ingested by hunter-shot 

mallards at Sacramento Refuge...........................................................110

Table 12. Comparison of lead and steel shot ingested by hunter-shot 

mallards at Sacramento, Tule Lake, and Ridgefield Refuges. .........110

Table 13. Ranks of three wildlife dependent activities (California 

Department of Parks and Recreation 2003). ......................................113

Table 14. Refuge Visitation Trends FY 2002-2006.............................117

Table 15. Primary Duck Species Harvested on the Sacramento 

Complex (2004-2006 Season). ...............................................................120

Table 16. Primary Goose Species Harvested on the Sacramento 

Complex (2004-2006 Season). ...............................................................121

Table 17. Sacramento Refuge Hunting Conditions............................123

Table 18. Delevan Refuge Hunting Conditions. .................................126

Table 19. Colusa Refuge Hunting Conditions. ...................................128

Table 20. Sutter Refuge Hunting Conditions. ....................................129

Table 21. Estimated Initial Capital Outlay to Fully Implement the 

CCP. ........................................................................................................188

Table 22. Estimated Annual Cost to Fully Implement the CCP1

.....190

v 
Appendices

Appendix A Environmental Assessment 

Appendix B Compatibility Determinations 

Appendix C Hunt Plan 

Appendix D Visitor Services Plan 

Appendix E Habitat Management Plan 

Appendix F Integrated Pest Management Plan 

Appendix G Resource Inventory and Monitoring Plan 

Appendix H Waterfowl Disease Contingency Plan 

Appendix I Water Management Plan 

Appendix J Fire Management Plan 

Appendix K Wildlife and Plant Species List 

Appendix L Compliance with Section 7 of the Endangered 

Species Act 

Appendix M Applicable Laws and Plans 

Appendix N List of Planning Team Members 

Appendix O Wilderness Review 

Appendix P Tree Reduction Operations Plan 

vi 
2047 

Acronyms and Abbreviations 

Colusa Basin Drain 

ACOE U.S. Army Corps of Engineers 

ADA Americans with Disabilities Act 

AHMP Annual Habitat Management Plan 

AHPA Archaeological and Historic Preservation Act 

ARPA Archaeological Resources Protection Act 

ATV All terrain vehicle 

BLM Bureau of Land Management 

BMP Best Management Practice 

BOR Bureau of Reclamation 

CALFED California Bay-Delta Program 

Cal Fire California Fire (also California Department of 

Forestry, CDF) 

CCP Comprehensive Conservation Plan 

CD Compatibility Determination 

CDF California Department of Forestry (also, Cal 

Fire) 

CDFG California Department of Fish and Game 

CDPR California Department of Parks and 

Recreation 

Cfs Cubic feet per second 

CFR Code of Federal Regulations 

CVJV Central Valley Joint Venture 

Complex Sacramento National Wildlife Refuge Complex 

CSU Chico California State University at Chico 

CWA California Waterfowl Association 

CVP Central Valley Project 

CVPIA Central Valley Project Improvement Act 

DMBM Division of Migratory Bird Management 

DOI Department of the Interior 

DU Ducks Unlimited 

DWR Department of Water Resources 

EA Environmental Assessment 

EE Environmental Education 

EPA U.S. Environmental Protection Agency 

ESA Endangered Species Act 

ESU Evolutionary Significant Unit 

FR Federal Register 

FTE Full-time Equivalent 

FY Fiscal Year 

GIS Global Information System 

GCID Glenn-Colusa Irrigation District 

GGS Giant Garter Snake 

GPS Global Positioning System 

Improvement Act National Wildlife Refuge System 

Improvement Act of 1997 

IPM Integrated Pest Management 

MOU Memorandum of Understanding 

MRF Mixed riparian forest 

NEPA National Environmental Policy Act 

vii 
NRHP National Register of Historic Places 

NOAA National Oceanic and Atmospheric 

Administration 

NOI Notice of Intent 

NOA Notice of Availability 

NWR National Wildlife Refuge (also, Refuge) 

NWRS National Wildlife Refuge System (also, Refuge 

System) 

PRBO Point Reyes Bird Observatory, PRBO 

Conservation Science 

PUP Pesticide Use Permit 

Refuge National Wildlife Refuge (also, NWR) 

Refuge System National Wildlife Refuge System (also, 

NWRS) 

Service U.S. Fish and Wildlife Service (also, USFWS) 

SoC Species of Concern 

SUP Special Use Permit 

SFW Seasonally flooded wetland 

SW Summer water 

T&E Threatened and Endangered Species 

TNC The Nature Conservancy 

USFWS U.S. Fish and Wildlife Service (also, Service) 

USGS U.S. Geological Survey 

VORF Valley oak riparian forest 

WG Watergrass 

WMA Wildlife Management Area 

WS Willow scrub 

WUI Wildland Urban Interface 

viii 
Introduction 

Chapter 1. Introduction and 

Background 

1. Introduction 

This document is a Draft Comprehensive Conservation Plan (CCP) 

designed to guide management of Sacramento, Delevan, Colusa, and 

Sutter National Wildlife Refuges (Refuges) for the next fifteen years. 

The U. S. Fish and Wildlife Service (Service) manages the Refuges as 

part of the Sacramento National Wildlife Refuge Complex (Complex) 

located in the Sacramento Valley of California (Figure 1) 

approximately ninety miles north of the city of Sacramento. 

The Draft CCP and accompanying Environmental Assessment (EA) 

address the Service’s legal mandates, policies, goals, and National 

Environmental Policy Act (NEPA) compliance. The EA (Appendix A) 

presents a range of administrative, habitat management, and visitor 

services alternatives that consider issues and opportunities on the 

Refuges. The Service’s initial proposal for future management of the 

Refuges is presented in the EA. Chapter 4 of the CCP describes the 

goals, objectives, and strategies for the Service’s preferred 

alternative (Alternative C). The final CCP will be developed through 

modifications made during the internal and public review processes. 

The CCP is accompanied by new and/or updated plans: a Hunting 

Plan (Appendix C), Visitor Services Plan (Appendix D), Integrated 

Pest Management Plan (Appendix F), Inventory and Monitoring Plan 

(Appendix G), Waterfowl Disease Contingency Plan (Appendix H), 

and Tree Reduction Operations Plan (Appendix P). Other existing 

plans that will remain in place include annual Habitat Management 

Plans (Appendix E), annual Water Management Plans (Appendix I), 

Fire Management Plan (Appendix J), Continuity of Operations Plan, 

and Safety Plan. 

The CCP is divided 

into five chapters: 

Chapter 1, 

Introduction; Chapter 

2, Planning Process; 

Chapter 3, Refuge 

Environment; 

Chapter 4, Planned 

Refuge Management 

and Programs; and 

Chapter 5, Plan 

Implementation. 

Sacramento National Wildlife Refuge 

Photo by Steve Emmons 

Comprehensive Conservation Plan 1 
Figure 1. Sacramento Refuge Complex Map. 

Chapter 1 

2 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Introduction 

2. Purpose of and Need for Plan 

Currently, individual Refuge Management Plans (USFWS 1988) 

guide the Sacramento, Delevan, Colusa, and Sutter Refuges. The 

National Wildlife Refuge System Improvement Act of 1997 (16 

United States Code [USC] 668dd-668ee) (Improvement Act) requires 

that all refuges be managed in accordance with an approved CCP by 

2012. Under the Improvement Act, the National Wildlife Refuge 

System (Refuge System) is to be consistently directed and managed 

to fulfill the specific purpose(s) for which each refuge was established 

as well as the Refuge System Mission. The planning process helps the 

Service achieve the refuge purposes and the Refuge System mission 

by identifying specific goals, objectives, and strategies to implement 

on each Refuge. 

The purposes of this CCP are to: 

 Provide a clear statement of direction for the future management 

of the Refuges. 

 Provide long-term continuity in Refuge management. 

 Communicate the Service’s management priorities for the 

Refuges to their partners, neighbors, visitors, and the general 

public. 

 Provide an opportunity for the public to help shape the future 

management of the Refuges. 

 Ensure that management programs on the Refuges are 

consistent with the mandates of the Refuge System and the 

purposes for which the Refuges were established. 

 Ensure that the management of the Refuges is consistent with 

Federal, State, and local plans. 

 Provide a basis for budget requests to support the Refuges’ needs 

for staffing, operations, maintenance, and capital improvements. 

3. Legal and Policy Guidance 

National Wildlife Refuges are guided by the purposes of the 

individual refuge, mission and goals of the Refuge System, and 

Service policy, laws, and international treaties. Relevant guidance 

includes the National Wildlife Refuge System Administration Act of 

1966, as amended by the Improvement Act, Refuge Recreation Act of 

1962, selected portions of the Code of Federal Regulations, and the 

Service Manual. 

Refuges are also governed by a variety of other laws, treaties and 

executive orders pertaining to the conservation and protection of 

natural and cultural resources (refer to Appendix M for additional 

information about these laws and executive orders). 

3.1. National Wildlife Refuge System Improvement Act 

The Improvement Act, which amends the National Wildlife Refuge 

System Administration Act of 1966, provides comprehensive 

legislation on how the Refuge System should be managed and used 

by the public. The Improvement Act: 

Comprehensive Conservation Plan 3 
Chapter 1 

 Identified a new mission statement for the Refuge System. 

 Established six priority public uses (hunting, fishing, wildlife 

observation and photography, environmental education and 

interpretation). 

 Emphasized conservation and enhancement of the quality and 

diversity of fish and wildlife habitat. 

 Stressed the importance of partnerships with Federal and State 

agencies, Tribes, non-governmental organizations, industry, and 

the general public. 

 Mandated public involvement in decisions on the acquisition and 

management of refuges. 

 Required, prior to acquisition of new refuge lands, identification 

of existing compatible wildlife-dependent uses that would be 

permitted to continue on an interim basis pending completion of 

comprehensive conservation planning. 

The Improvement Act establishes the responsibilities of the 

Secretary of the Interior for managing and protecting the Refuge 

System; requires a CCP for each refuge by the year 2012; and 

provides guidelines and directives for the administration and 

management of all areas in the Refuge System, including wildlife 

refuges, areas for the protection and conservation of fish and wildlife 

threatened with extinction, wildlife ranges, game ranges, wildlife 

management areas, or waterfowl production areas. 

3.2. Appropriate Use Policy 

This policy describes the initial decision process the refuge manager 

follows when first considering whether or not to allow a proposed use 

on a refuge. The refuge manager must find a use appropriate before 

undertaking a compatibility review of the use. An appropriate use, as 

defined by the Appropriate Use Policy (603 FW 1 of the Service 

Manual), is a proposed or existing use on a refuge that meets at least 

one of the following four conditions: 

 The use is a wildlife-dependant recreational use as identified in 

the Improvement Act. 

 The use contributes to the fulfilling of the refuge purpose(s), the 

Refuge System mission, or goals or objectives described in a 

refuge management plan approved after October 9, 1997, the date 

the Improvement Act was signed into law. 

 The use involves the take of fish and wildlife under State 

regulations. 

 The use has been found to be appropriate as specified in section 

1.11 (603 FW 1 of the Service Manual). 

If an existing use is not appropriate, the refuge manager will 

eliminate or modify the use as expeditiously as practicable. If a new 

use is not appropriate, the refuge manager will deny the use without 

determining compatibility. If a use is determined to be an appropriate 

4 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Introduction 

refuge use, the refuge manager will then determine if the use is 

compatible (see Compatibility section below). Although a use may be 

both appropriate and compatible, the refuge manager retains the 

authority to not allow the use or modify the use. Uses that have been 

administratively determined to be appropriate are the six wildlifedependent recreational uses (hunting, fishing, wildlife observation 

and photography, environmental education, and interpretation) and 

take of fish and wildlife under State regulations. 

3.3. Compatibility Policy 

Lands within the Refuge System are different from other multiple 

use public lands in that they are closed to all public uses unless 

specifically and legally opened. The Improvement Act states “... the 

Secretary shall not initiate or permit a new use of a Refuge or 

expand, renew, or extend an existing use of a Refuge, unless the 

Secretary has determined that the use is a compatible use and that 

the use is not inconsistent with public safety.” 

In accordance with the Improvement Act, the Service has adopted a 

Compatibility Policy (603 FW 2 of the Service Manual) that includes 

guidelines for determining if a use proposed on a National Wildlife 

Refuge is compatible with the purposes for which the refuge was 

established. A compatible use is defined in the policy as a proposed or 

existing wildlife-dependent recreational use or any other use of a 

National Wildlife Refuge that, based on sound professional judgment, 

will not materially interfere with or detract from the fulfillment of the 

Refuge System mission or the purposes of the Refuge. Sound 

professional judgment is defined as a finding, determination, or 

decision that is consistent with the principles of sound fish and 

wildlife management and administration, available science and 

resources (funding, personnel, facilities, and other infrastructure), 

and applicable laws. The Service strives to provide priority public 

uses when they are compatible. If financial resources are not 

available to design, operate, and maintain a priority use, the refuge 

manager will take reasonable steps to obtain outside assistance from 

the State and other conservation interests. 

When a determination is made as to whether a proposed use is 

compatible or not, this determination is provided in writing and is 

referred to as a compatibility determination. An opportunity for 

public review and comment is required for all compatibility 

determinations. For compatibility determinations prepared 

concurrently with a CCP or step-down management plan, the 

opportunity for public review and comment is provided during the 

public review period for the draft plan and associated NEPA 

document. 

Comprehensive Conservation Plan 5 
 

4. The U.S. Fish and Wildlife Service 

The Service is the primary Federal agency responsible for 

conserving, protecting, and enhancing fish and wildlife and their 

habitats for the continuing benefit of the American people. Although 

the Service shares this responsibility with other Federal, State, 

Tribal, local, and private entities, the Service has specific 

responsibilities for migratory birds, threatened and endangered 

species, anadromous and interjurisdictional fish, and certain marine 

mammals. These are referred to as Federal Trust Species. The 

Service also manages the Refuge System and National Fish 

Hatcheries; enforces Federal wildlife laws and international treaties 

on importing and exporting wildlife; assists State fish and wildlife 

programs; and helps other countries develop wildlife conservation 

programs. 

Chapter 1 

3.4. Biological Integrity, Diversity and Environmental Health 

Policy 

In addition, the Improvement Act directs the Service to “ensure that 

the biological integrity, diversity, and environmental health of the 

Refuge System are maintained for the benefit of present and future 

generations of Americans...” To implement this directive, the Service 

has issued the Biological Integrity, Diversity and Environmental 

Health Policy (601 FW 3 of the Service Manual), which provides 

policy for maintaining and restoring, where appropriate, the 

biological integrity, diversity, and environmental health of the Refuge 

System. The policy is an additional directive for refuge managers to 

follow while achieving Refuge purpose(s) and Refuge System mission. 

It provides for the consideration and protection of the broad 

spectrum of fish, wildlife, and habitat resources found on Refuges and 

associated ecosystems. Further, it 

provides refuge managers with an 

evaluation process to analyze their 

refuge and recommend the best 

management direction to prevent 

further degradation of 

environmental conditions and 

restore lost or severely degraded 

components where appropriate and 

in concert with refuge purposes 

and the Refuge System mission. 

When evaluating the appropriate 

management direction for refuges, 

refuge managers will use sound 

professional judgment to 

determine their refuges’ 

contribution to biological integrity, 

diversity, and environmental health 

at multiple landscape scales. 

 Greater white-fronted goose 

Photo by Mike Peters 

6 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Introduction 

The mission of the Service is: 

“Working with others to conserve, protect, and enhance fish, wildlife 

and plants and their habitats for the continuing benefit of the 

American people.” 

5. The National Wildlife Refuge System 

In 1903, President Theodore Roosevelt named Florida’s Pelican 

Island the nation’s first bird sanctuary, which along with other 

sanctuaries and preserves evolved into the National Wildlife Refuge 

System. Since that time, the Refuge System has grown to more than 

97 million acres. It includes 548 refuges, at least one in every state 

and many U.S. territories, and over 3,000 Waterfowl Production 

Areas. The Refuge System is the world’s largest collection of lands 

and waters set aside specifically for the conservation of wildlife and 

ecosystem protection. The needs of wildlife and their habitats come 

first on refuges, in contrast to other public lands managed for 

multiple uses. The Refuge System provides important habitat for 

native plants and many species of mammals, birds, fish, and 

threatened and endangered species. 

The mission of the Refuge System, as stated in the Improvement Act, 

is: 

“To administer a national network of lands and waters for the 

conservation, management, and where appropriate, restoration of 

the fish, wildlife and plant resources and their habitats within the 

United States for the benefit of present and future generations of 

Americans” (16 USC 668dd et seq.). 

The goals of the Refuge System, as defined in the Refuge System 

Mission and Goals and Refuge Purposes Policy (601 FW 1 of the 

Service Manual) are to: 

 Conserve a diversity of fish, wildlife, and plants and their 

habitats, including species that are endangered or threatened 

with becoming endangered. 

 Develop and maintain a network of habitats for migratory birds, 

anadromous and interjurisdictional fish, and marine mammal 

populations that is strategically distributed and carefully 

managed to meet important life history needs of these species 

across their ranges. 

 Conserve those ecosystems, plant communities, wetlands of 

national or international significance, and landscapes and 

seascapes that are unique, rare, declining, or underrepresented in 

existing protection efforts. 

 Provide and enhance opportunities to participate in compatible 

wildlife-dependent recreation (hunting, fishing, wildlife 

observation and photography, and environmental education and 

interpretation). 

Comprehensive Conservation Plan 7 
Chapter 1 

 Foster understanding and instill appreciation of the diversity and 

interconnectedness of fish, wildlife, and plants and their habitats. 

Collectively, these goals articulate the foundation for our stewardship 

of the Refuge System and define the unique and important niche it 

occupies among the various Federal land systems. These goals will 

help guide development of specific management priorities during 

development of CCPs. 

In addition, the guiding principles of the Refuge System are: 

 We are land stewards, guided by Aldo Leopold's teachings that 

land is a community of life and that love and respect for the land 

is an extension of ethics. We seek to reflect that land ethic in our 

stewardship and to instill it in others. 

 Wild lands and the perpetuation of diverse and abundant wildlife 

are essential to the quality of the American life. 

 We are public servants. We owe our employers, the American 

people, hard work, integrity, fairness, and a voice in the 

protection of their trust resources. 

 Management, ranging from preservation to active manipulation of 

habitats and populations, is necessary to achieve Refuge System 

and Service missions. 

 Wildlife-dependent uses involving hunting, fishing, wildlife 

observation, photography, interpretation, and education, when 

compatible, are legitimate and appropriate uses of the Refuge 

System. 

 Partnerships with those who want to help us meet our mission are 

welcome and indeed essential. 

 Employees are our most valuable resource. They are respected 

and deserve an empowering, mentoring, and caring work 

environment. 

 We respect the rights, beliefs, and opinions of our neighbors. 

6. The Sacramento National Wildlife Refuge Complex 

For thousands of years the Sacramento Valley has provided a winter 

haven for ducks, geese, and swans. Waterfowl migrate here by the 

millions from as far away as the Arctic regions of Alaska, Canada, 

and Siberia. The five national wildlife refuges and three wildlife 

management areas of the Sacramento National Wildlife Refuge 

Complex (Complex) represent an island of habitat in a sea of 

Sacramento Valley agriculture (Figure 1). 

The Valley is an extensive agricultural area that has historically been 

a major wintering area for millions of ducks and geese. Lands that 

surround the Refuges are mostly irrigated rice lands. Some dairy 

production as well as various crops including safflower, barley, wheat, 

and alfalfa is also present. The Valley is bordered by the Sierra 

Nevada Range to the east and Coast Range to the west. Topography 

is flat with a gentle slope to the southeast towards the Sacramento 

River. Predominant soil types are poorly drained alkaline clays. 

8 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Introduction 

The Complex represents a small portion of the vast seasonal wetlands 

and grasslands that once existed in the Sacramento Valley. Millions 

of waterfowl migrated south in the Pacific Flyway to winter in the 

Valley among resident waterbirds, deer, elk, pronghorn, and grizzly 

bear. Natural habitat was replaced with rice and other crops with the 

development of agriculture during the late 1800s and early 1900s. 

Waterfowl substituted some of these farm crops for their original 

wetland foods, causing serious crop losses for farmers. 

Today, 90 to 95 percent of California's wetlands are gone, along with 

the grizzly bear (Holland 1978, Gilmer et al. 1982, Frayer et al. 1989, 

Kempka and Kollasch 1990). Constructed levees now confine the 

rivers for irrigation and flood control, preventing the natural flooding 

of wetlands. Despite these changes, birds continue to fly their ancient 

migration routes along the Pacific Flyway and crowd into the 

remaining wintering habitat. The Complex provides a significant 

amount of the wintering habitat that supports waterfowl and many 

other migratory birds in the Sacramento Valley. The Complex 

currently supports nearly 300 species of birds. 

In 1937, when Sacramento National Wildlife Refuge was established, 

Refuge staff worked to transform many of the Refuge's dry, alkaline 

lands into productive managed wetlands. Some of these areas were 

used for growing grain crops to attract waterfowl away from crops on 

private lands. Three additional Refuges were created in the 1940s 

through the 1980s, forming the Sacramento National Wildlife Refuge 

Complex. These Refuges, including Delevan, Colusa, and Sutter, 

were established to provide wintering habitat for waterfowl and in 

some cases to reduce crop damage. The Refuges consist of 

approximately 23,000 acres of wetlands, vernal pools, alkali meadows, 

grassland, and riparian habitats. During spring, the Refuges drain 

seasonal wetlands, the most common habitat type, and allow them to 

dry out over the summer to encourage plant growth on the moist, 

exposed soil. Re-flooding in the fall makes seeds and plants available 

for wildlife. Water management, prescribed burns, disking, and 

mowing are some of the techniques used to manage wetland habitats. 

The fifth refuge, Sacramento River Refuge, was established in 1989 

to help protect and restore riparian habitat along the Sacramento 

River as it meanders through the Sacramento Valley from Red Bluff 

to Colusa. This Refuge is not included in this CCP and is covered 

under the Sacramento River Refuge Final CCP released in July 2005. 

The Complex’s three wildlife management areas North Central 

Valley, Willow Creek – Lurline, and Butte Sink, are also not included 

in this CCP. These areas will be addressed in a separate CCP at a 

later date. 

Comprehensive Conservation Plan 9 
Chapter 1 

7. Sacramento National Wildlife Refuge 

In January 1937, the Federal government purchased the 10,775-acre 

Spalding Ranch, located south of “The Willows” and christened it the 

Sacramento Migratory Waterfowl Refuge. It was established by 

Executive Order 7562 and was acquired with funds from the 

Emergency Conservation Fund Act of 1933 to provide refuge and 

breeding habitat for migratory birds and other wildlife. In 1971, eight 

additional acres were purchased with Land and Water Conservation 

Funds increasing the Refuge to 10,783 acres. In 2003, the State of 

California Conservation Board donated the 36-acre Goldworthy 

property to the Refuge to protect the site from proposed commercial 

development. 

Entrance sign (1938) 

USFWS Photo 

The Refuge was created on an open plain of short grasses, shrubs, 

and forbs known as the Colusa Plains. This area has a gradual slope 

to the southeast toward the Sacramento River. The Colusa Plains was 

noteworthy; with the exception of “The Willows,” a small treeabundant watering hole, the area was a vacant, windswept plain 

(Wagon Wheels 1956). Refuge lands consisted primarily of a dry 

alkaline plain, with fewer than 1,000 wetland and 4,800 deteriorated 

crop acres present. Beginning with the Civilian Conservation Corp’s 

“Camp Sacramento” during the late 1930s, levees, water control 

structures, and delivery ditches were constructed to create and 

sustain wetlands across the majority of the Refuge. 

10 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

 

Introduction 

Constructing delivery ditches at Sacramento Refuge (1938) 

USFWS Photo 

Today, the Refuge is known as the Sacramento National Wildlife 

Refuge, and it functions as the headquarters for the entire Complex. 

The Refuge is currently 10,819 acres (Figure 1) and is comprised of 

approximately 7,086 acres of managed wetlands (summer wetlands 

and seasonally flooded wetlands) and 3,360 acres of unmanaged 

wetlands, grasslands, alkali meadows, vernal pools, and riparian 

habitats. While most of these habitats no longer reflect the original 

landscape, management programs do attempt to mimic the natural 

conditions that once occurred throughout the Sacramento Valley on a 

much grander scale. 

Wintering waterfowl have become increasingly dependent on these 

artificially created and maintained habitats because 90 to 95 percent 

of California’s wetland habitat is gone, its water supply is highly 

regulated, and its human population is increasing with many 

associated impacts. As a result, the Service must now intensively 

manage the Refuge in order to provide a consistent quantity and 

quality of habitats to compensate for habitat losses due to 

agricultural and urban development. Many types of species benefit 

from these efforts, including those which are rare and abundant, 

resident and migratory, and game and non-game. 

The Refuge currently supports approximately 250 species of birds; 

most notable are the huge wintering concentrations (November - 

January) of 500,000 to 750,000 ducks and 200,000 geese. This is quite 

a change, as historically the area supported many more geese than 

ducks, but the advent of rice culture in the early 1900s helped shift 

the balance. Raptor numbers swell as the waterfowl numbers 

increase, including bald eagles and peregrine falcons. In addition, 

shorebird numbers peak in the spring, while some waterfowl and 

numerous migratory songbird species nest here during the summer. 

The Refuge is also home to numerous rare, threatened or endangered 

species, of which eight are federally listed; many of these are 

associated with a special type of wetland called vernal pools. The 

Comprehensive Conservation Plan 11 
Chapter 1 

alkali meadow and vernal pool habitats on the Refuge represent some 

of the largest remaining areas of this habitat type in California. 

The visitor center is located in the Refuge headquarters office. 

Refuge staff is available to help plan a visit, answer questions and 

assist visitors. Visitors can experience a wildlife diorama and 

discovery room, and browse at our bookstore. Recreation activities on 

the Refuge include hunting, wildlife observation, photography, 

environmental education, and interpretation. There is a six-mile auto 

tour with an interpretive radio broadcast and a two-mile walking 

trail, which are open year-round. A multi-level viewing platform on 

the auto tour gives a panoramic view of the Sacramento Valley and 

provides visitors with opportunities to observe wildlife from among 

the treetops. Two photography blinds are available by advance 

reservation. Hunting of waterfowl, coot, common moorhen, snipe, and 

pheasant is permitted on the southern portion of the Refuge on 

Saturdays, Sundays, and Wednesdays during the legal seasons. The 

hunt program is cooperatively managed with the California 

Department of Fish and Game (CDFG) and offers spaced blind, 

assigned pond, and free roam hunting opportunities via a permit 

system. 

8. Delevan National Wildlife Refuge 

The Delevan Refuge was authorized in 1962 by the Migratory Bird 

Conservation Commission, and purchased with funds made available 

by the Migratory Bird Hunting and Conservation Stamp Act. The 

Refuge was established to provide sanctuary for migratory birds. The 

Refuge was formed by the purchase of two parcels, the 5,314-acre 

Charles W. Welch Ranch in 1962 and 320 acres belonging to Jesse 

Iverson in 1963. In 1991, the 80-acre Rennick property was 

transferred from the Farmers Home Administration and is now 

managed as part of Delevan Refuge. The last 163-acre parcel was 

purchased from Florence Watt Trust in 1994 under the authority of 

the Migratory Bird Conservation Act. 

Similar to Sacramento Refuge, Delevan Refuge was created on an 

open plain of short grasses, shrubs, and forbs known as the Colusa 

Plains. This area has a gradual slope toward the Sacramento River to 

the southeast. Much of the land was flooded during the winter, and at 

one time there were even two lakes (Twin Lakes Gun Club) on the 

Refuge area. These historic flood patterns continue today as a major 

drain for the western Sacramento Valley, the Colusa Basin Drain 

(2047). The Colusa Basin Drain runs along much of Delevan’s eastern 

boundary, often resulting in significant annual flooding of the Refuge 

from December through February. 

Today, the Refuge consists of 5,877 acres (including the 80-acre 

Rennick property) (Figure 1). It is comprised of a combination of 

approximately 4,600 acres of managed wetlands (summer wetlands 

and seasonally flooded wetlands) and approximately 984 acres of 

12 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

Introduction 

unmanaged wetlands, grasslands, alkali meadows, vernal pools, and 

riparian habitats. An endemic plant species, palmate-bracted bird’sbeak is of particular interest in the alkali meadows. Listed as 

endangered on both Federal and State lists, Delevan Refuge is home 

to the largest remaining population, with an average annual 

population of 150,000 to 200,000 plants. 

Palmate-bracted bird’s-beak 

Photo by Joe Silveria 

Waterfowl numbers peak at nearly 415,000 ducks and over 150,000 

geese. The tule white-fronted goose is especially important as their 

Pacific Flyway population is small and a significant portion of the 

population utilizes this Refuge during the fall and winter months. The 

Refuge also supports significant breeding colonies of tricolored 

blackbirds. 

Public recreation activities include wildlife observation and 

photography from perimeter roads. Hunting of waterfowl, coot, 

common moorhen, snipe, and pheasant is permitted on the southern 

portion of the Refuge on Saturdays, Sundays, and Wednesdays 

during the legal seasons. The cooperatively managed hunt program 

with the CDFG offers spaced hunt site, assigned pond, and free roam 

hunting opportunities via a permit system. 

9. Colusa National Wildlife Refuge 

On December 5, 1944, the Migratory Bird Conservation Commission 

approved the purchase of the W.H. O’Hair tract containing 2,384 

acres to create the Colusa Refuge. The purchase was made in 1945 

with funds made available by the Migratory Bird Hunting and 

Conservation Stamp Act. 

On May 18, 1948, an Act of Congress (16 U.S.C. 695-695c, otherwise 

known as the Lea Act) made provisions to fund, acquire, and maintain 

wildlife management and control areas in the State of California. The 

Lea Act targeted the problem of agricultural depredation and funds 

were available for “the construction of dams, dikes, ditches, buildings, 

and other necessary improvements and for the purchase, planting, 

Comprehensive Conservation Plan 13 
 

 

 

Chapter 1 

growing, and harvesting of grains and other crops for the feeding of 

waterfowl and other wildlife frequenting the localities where such 

lands may be purchased or rented.” It also included provisions to 

permit hunting. 

By the authority, purpose, and funding under the Lea Act, additional 

land was acquired for Colusa Refuge. On February 21, 1949, three 

tracts of land (760 acres) belonging to Libbie Jacobson were 

approved for purchase and acquired by the Refuge. Also under the 

provisions of the Lea Act, the 337-acre Wallace R. Lynn tract, the 

480-acre Charles L. Stone tract, and the 80-acre Joseph T. Garibaldi 

tract were approved for purchase on April 27, 1949, February 19, 

1952, and March 27, 1952 respectively. 

The Refuge was established to provide sanctuary for migratory birds 

and to alleviate crop depredation. Today, depredation problems have 

decreased in magnitude due in part to reduced numbers of waterfowl, 

changes in agricultural practices, and increases in wetland quality 

and quantity. 

From 1996 to 2002, an additional 646 acres were acquired under 

North Central Valley Wildlife Management Area, and are managed 

as part of the Refuge. Included in the 646 acres is a 448-acre parcel 

located south of Abel Road and west of Ohm road that was acquired 

in 1995, a 19-acre tract acquired in 1996, a 119-acre acquired in 2002, 

and a 60-acre parcel acquired in 2006. 

Today the Refuge consists of over 4,686 acres, which includes the 646 

acres acquired via North Central Valley Wildlife Management Area 

(Figure 1). It is comprised of approximately 3,347 acres of managed 

wetlands (summer wetlands and seasonally flooded wetlands) and 

approximately 1,191 acres of unmanaged wetlands, grasslands, alkali 

meadows, vernal pools, and riparian habitats. The Refuge lies in the 

Colusa Basin and is bisected by the Colusa Basin Drain, which drains 

the Basin southeast to the Sacramento River. The low topography 

and presence of the Colusa Basin Drain makes Refuge lands subject 

to regular winter flooding. 

Currently, peak numbers of waterfowl can 

exceed 200,000 ducks and over 75,000 

geese. In addition, significant numbers of 

giant garter snakes (Federal-listed 

threatened species) and palmate-bracted 

bird’s-beak occur on the Refuge, as does 

the second largest acreage of vernal pools 

on the Complex. 

14 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 

Snow geese on Colusa Refuge 

Photo by Mike Peters 
 

 

Introduction 

Public recreation activities include wildlife observation and 

photography on a three-mile self-guided auto tour and a one-mile 

walking trail along a riparian slough and wetland. The auto tour and 

walking trail are open sunrise to sunset, year-round, with interpretive 

panels and pamphlets available at a kiosk. A photography blind is 

available by advanced reservation. Hunting of waterfowl, coot, 

common moorhen, snipe, and pheasant is permitted on the southern 

portion of the Refuge on Saturdays, Sundays, and Wednesdays 

during the legal seasons. The cooperatively managed hunt program 

with the CDFG offers both assigned pond and free roam hunting 

opportunities via a permit system. 

10. Sutter National Wildlife Refuge 

On December 5, 1944, the Migratory Bird Conservation Commission 

approved the purchase of the 306-acre S.G. Harris tract. This land 

was acquired on May 9, 1945, establishing the Refuge with funds 

made available by the Migratory Bird Hunting and Conservation 

Stamp Act. On December 5, 1944, approval was also given to 

purchase 141 acres from the State of California, 205 acres from the 

Sophie Davis Estates, and the 425-acre Grover C. Shannon tract. 

Funds provided for by the Lea Act were used to acquire 522 acres 

from Elizabeth P. Kilgarif in 1952 and 672 acres from the Sutter 

Home Investment Company in 1953. The last 231 acres was 

purchased from the State of California in 1956 with Lea Act funds. 

The Refuge was established to provide sanctuary for migratory birds 

and alleviate crop depredation. Today, depredation problems have 

decreased due in part to reduced numbers of waterfowl, changes in 

agricultural practices, and increases in wetland quality and quantity. 

Sutter Refuge is the only refuge in the Complex with privately-owned 

lands included within the approved acquisition boundary that have 

not been acquired (Figure 1). While there are no current plans to 

purchase these lands, the Service would consider it if the opportunity 

arises. 

Sutter Refuge is located in the Sutter Basin between the Sacramento 

and Feather rivers (Figure 1). Historically, these rivers and Butte 

Creek flooded the Sutter Basin during the winter and spring. In the 

1920s, the Sutter Bypass levees were constructed to channel these 

floodwaters. Over 80 percent of the Refuge lies within the northern 

portion of the Bypass and gradually slopes to the south. When 

floodwaters flow in the Bypass, the Refuge can be under at least 10 

feet of water. 

Sutter Refuge has 2,591 total acres, of which over 2,000 

(approximately 80 percent) are located inside the Bypass. Habitat 

types, both inside and outside the Bypass, consist of approximately 

1,881 acres of seasonal and summer wetlands and approximately 674 

acres of unmanaged wetlands, grasslands, and riparian habitats. 

Comprehensive Conservation Plan 15 
 

 

White-faced ibis

Photo by Mike Peters 

Chapter 1 

Waterfowl numbers peak later than most other Refuges in the 

Complex (January – February) and include nearly 73,000 ducks and 

100,000 geese. In addition, its border 

canals and associated riparian habitat 

ensure Sutter Refuge has one of the 

highest frequencies of yellow-billed 

cuckoos (Federal candidate species) in 

the Complex. 

Public recreation activities on the 

Refuge are limited to hunting of 

waterfowl, coot, common moorhen, 

snipe, and pheasant on the southern 

portion of the Refuge on Saturdays, 

Sundays, and Wednesdays during the 

legal seasons. The cooperatively 

managed hunt program with the CDFG 

consists of free roam hunting 

opportunities via a permit system. 

 

11. Refuge Purposes 

The Service acquires Refuge System lands under a variety of 

legislative acts and administrative orders. The official purpose or 

purposes for a refuge are specified in or derived from the law, 

proclamation, executive order, agreement, public land order, donation 

document, or administrative memorandum establishing, authorizing, 

or expanding a refuge, refuge unit, or refuge subunit. The Service 

defines the purpose of a refuge when it is established or when new 

land is added to an existing refuge. These purposes, along with the 

Refuge System mission, are the driving forces in developing refuge 

vision statements, goals, objectives and strategies in the CCP. The 

purposes also form the standard for determining if proposed refuge 

uses are compatible. 

The Refuge purposes are: 

11.1. Sacramento Refuge Purposes 

“... as a refuge and breeding ground for migratory birds and 

other wildlife...” Executive Order 7562, February. 27, 1937. 

“... for use as an inviolate sanctuary, or for any other 

management purpose, for migratory birds.” 16 U.S.C. 715d 

(Migratory Bird Conservation Act of 1929). 

“... to conserve (A) fish or wildlife which are listed as 

endangered species or threatened species .... or (B) plants ...” 

16 U.S.C. ¤ 1534 (Endangered Species Act of 1973). 

16 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

Introduction 

“... suitable for (1) incidental fish and wildlife-oriented 

recreational development, (2) the protection of natural 

resources, (3) the conservation of endangered species or 

threatened species ...” 16 U.S.C. 460k-1 “... the Secretary ... 

may accept and use ... real ... property. Such acceptance may 

be accomplished under the terms and conditions of restrictive 

covenants imposed by donors ...” 16 U.S.C. 460k-2 (Refuge 

Recreation Act of 1962 (16 U.S.C. 460k-460k-4), as amended). 

“... for the development, advancement, management, 

conservation, and protection of fish and wildlife resources ...” 

16 U.S.C. 742f(a)(4) “... for the benefit of the United States 

Fish and Wildlife Service, in performing its activities and 

services. Such acceptance may be subject to the terms of any 

restrictive or affirmative covenant, or condition of servitude 

...” 16 U.S.C. 742f(b)(1) (Fish and Wildlife Act of 1956). 

11.2. Delevan Refuge Purpose 

“... for use as an inviolate sanctuary, or for any other 

management purpose, for migratory birds.” 16 U.S.C. 715d 

(Migratory Bird Conservation Act of 1929). 

11.3. Colusa Refuge Purposes 

“... for use as an inviolate sanctuary, or for any other 

management purpose, for migratory birds.” 16 U.S.C. 715d 

(Migratory Bird Conservation Act of 1929). 

“... for the management and control of migratory waterfowl 

and other wildlife ...” 16 U.S.C. 695 (Lea Act of 1948). 

“... to conserve (A) fish or wildlife which are listed as 

endangered species or threatened species .... or (B) plants ...” 

16 U.S.C. 1534 (Endangered Species Act of 1973). 

11.4. Sutter Refuge Purposes 

“... for use as an inviolate sanctuary, or for any other 

management purpose, for migratory birds.” 16 U.S.C. 715d 

(Migratory Bird Conservation Act of 1929). 

“... for the management and control of migratory waterfowl 

and other wildlife ...” 16 U.S.C. 695 (Lea Act of 1948). 

“... suitable for (1) incidental fish and wildlife-oriented 

recreational development, (2) the protection of natural 

resources, (3) the conservation of endangered species or 

threatened species ...” 16 U.S.C. 460k-1 “... the Secretary ... 

may accept and use ... real ... property. Such acceptance may 

be accomplished under the terms and conditions of restrictive 

covenants imposed by donors ...” 16 U.S.C. 460k-2 (Refuge 

Recreation Act of 1962 (16 U.S.C. 460k-460k-4), as amended). 

Comprehensive Conservation Plan 17 
“... for the development, advancement, management, 

conservation, and protection of fish and wildlife resources ...” 

16 U.S.C. 742f(a)(4) “... for the benefit of the United States 

Fish and Wildlife Service, in performing its activities and 

services. Such acceptance may be subject to the terms of any 

restrictive or affirmative covenant, or condition of servitude 

...” 16 U.S.C. 742f(b)(1) (Fish and Wildlife Act of 1956). 

12. The Refuges’ Vision 

A vision statement is developed for each refuge or complex as part of 

the CCP process. Vision statements are grounded in the unifying 

mission of the Refuge System. They describe the desired future 

conditions of the refuge unit in the long term (more than 15 years) 

and are based on the refuge’s specific purposes, the resources 

present on the refuge, and any other relevant mandates. This CCP 

incorporates the following vision statement for the Sacramento, 

Delevan, Colusa, and Sutter Refuges. 

“Located in the Sacramento Valley of California, Sacramento, 

Delevan, Colusa, and Sutter National Wildlife Refuges are 

some of the most important wintering areas for waterfowl along 

the Pacific Flyway and in North America. The Refuges’ 

wetland, vernal pool, alkali meadow, grassland, and riparian 

communities will provide high-quality habitat for a diverse 

array of wildlife species including migratory waterfowl, 

shorebirds, birds of prey, and songbirds. These habitats will 

also provide food, water, and cover for threatened and 

endangered species including vernal pool plants and 

invertebrates, and giant garter snakes. 

Working with partners, the Refuges will provide a wide 

range of environmental education programs and promote 

high quality wildlife-dependent recreation in order to 

maintain a refuge support base and attract new visitors. 

Compatible wildlife-dependent recreational opportunities 

for hunting, wildlife observation, photography, 

environmental education, and interpretation will be 

provided on the Refuges.” 

13. Existing and New Partnerships 

In Fulfilling the Promise (USFWS 1999c), the Service identified the 

need to forge new and non-traditional alliances and strengthen 

existing partnerships with States, Tribes, non-profit organizations, 

and academia to broaden citizen and community understanding of 

and support for the Refuge System. The Service recognizes that 

strong citizen support benefits the Refuge System. Involving citizen 

groups in resource and management issues and decisions helps 

refuge managers gain an understanding of public concerns. Partners 

yield support for refuge activities and programs, raise funds for 

Chapter 1 

18 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Introduction 

projects, are activists on behalf of wildlife and the Refuge System, 

and provide support for important wildlife and natural resource 

issues. 

A variety of people including, but not limited to, scientists, birders, 

hunters, farmers, outdoor enthusiasts and students are keenly 

interested in the management of Complex, its fish and wildlife 

species, and its plants and habitats. This interest is demonstrated by 

the number of visitors the Refuges receive and the partnerships that 

have already developed. We will continue to form new partnerships 

with interested organizations, local civic groups, community schools, 

Federal, State, and County governments, Tribes, and other civic 

organizations. Refuge partners include: California Department of 

Fish and Game, U.S. Bureau of Reclamation, U.S. Geological Survey, 

California Department of Water Resources, Glenn-Colusa Irrigation 

District, Ducks Unlimited, California Waterfowl Association, Altacal 

Audubon, California State University - Chico, Point Reyes Bird 

Observatory, California Rice Commission, Kiwanis Club, Rotary 

Club, and Butte Sink Waterfowlers Association. 

14. Ecosystem Context 

The Central Valley consists of four physiographic regions: the 

Sacramento Valley, the San Joaquin Valley, the Tulare Basin, and the 

Sacramento-San Joaquin Delta (Warner and Hendrix 1985). The 

Refuges are within the Service's Central Valley/San Francisco Bay 

Ecoregion (Figure 2). 

The Complex can be put into an ecosystem context on many levels, 

including local, regional, national, international, or even global levels, 

on the variety and abundance of certain species and their habitats, 

extent of their range, or the geographic areas from or to which they 

migrate. Migratory birds come from breeding areas as far away as 

Siberia, Russia, Alaska, and the Canadian Arctic. Most spend the 

winter here, while others continue as far south as Central America to 

winter, only to pass through on their return trip in the spring. 

Seasonal wetlands and other habitats at the Complex provide 

essential food resources and resting areas for winter residents, birds 

continuing south, and returning spring migrants building up body 

reserves for their trip back to northern breeding areas. 

The Central Valley of California supports the greatest number of 

wintering waterfowl in the Pacific Flyway and is, one of the most 

important wintering areas in North America (CVJV 2006). This level 

of importance can also be applied to shorebirds and other waterbirds, 

with several wetland areas in the Central Valley designated as those 

of international importance. The Sacramento Valley, specifically, is 

designated as a part of the Western Hemispheric Shorebird Reserve 

Network (WHSRN). Seasonal wetlands at the Complex play a 

significant role in supporting all migratory waterbird species in the 

Valley. In some cases, the Complex alone may support the majority of 

Comprehensive Conservation Plan 19 
Chapter 1 

the Pacific Flyway’s wintering waterfowl. For example, in midOctober, 85 to 90 percent of the entire Pacific Flyway’s greater whitefronted geese may be on the Complex (350,000-400,000 in some recent 

years). The Complex has had peak duck numbers of over 2,000,000 in 

years when California totals from mid-winter waterfowl surveys have 

been three to four million, as indexed by the Mid-winter Indices. 

While the Central Valley is also an important breeding area for 

mallards and several other species of waterfowl and shorebirds, these 

birds make up a relatively small percentage of the overall use of the 

Complex on an annual basis. 

On a more local level, the Complex supports a variety of resident, 

migratory, and breeding wildlife species, native plants, and their 

habitats. Some are quite common, both in the Central Valley, the 

Flyway, and in North America. These would include a number of 

egret and heron species, white-faced ibis, black-tailed deer, and a 

variety of grassland and riparian birds. Other species are quite 

restricted in range. For example, the tricolored blackbird, yellowbilled magpie, and giant garter snake are species that occur almost 

exclusively in the Central Valley of California. In 2004, a single 

breeding colony of tricolored blackbirds on Delevan Refuge 

represented a significant proportion of the entire valley population 

and had the largest reproductive output of any colony of this species. 

Yellow-billed magpie 

Photo by Steve Emmons 

20 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Figure 2. Ecosystem Map. 

Introduction 

Comprehensive Conservation Plan 21 
Chapter 1 

Most of the alkali meadow, vernal pool, and short grassland habitats 

that once extensively occurred on the Sacramento Valley floor have 

been converted to agriculture or urban development. The Complex 

protects some of the largest remaining blocks of these habitats. As a 

result, the Complex supports a significant diversity and abundance of 

endemic plant and animal resources. In many cases species are rare, 

and in some cases, are listed as Federal and/or State endangered or 

threatened. There are seven threatened or endangered species that 

occur in vernal pool or alkali meadow habitats on the Complex, 

including three vernal pool invertebrates and four plants. The vast 

majority of the world’s population of palmate-bracted bird’s-beak, a 

rare Central Valley endemic and federally endangered plant, occurs 

on Delevan and Colusa Refuges. As habitat continues to dwindle with 

the expanse of urban development, areas such as the Complex 

become increasingly important to the conservation of these species. 

Appendix K provides a complete list of species, describes their 

migratory and breeding status at the Complex, and notes whether 

they are listed as endangered or threatened. 

In summary, the Complex plays a significant, and in some cases, 

critical role at the ecosystem level. Its support of abundance, 

diversity, or single species conservation makes it critically important 

to conservation in general. Whether permanent or seasonal wetlands, 

vernal pools or alkali meadows, just protecting these habitats is not 

enough to maintain their function in the ecosystem. Without proper 

management, most of these habitats would be consumed by an evergrowing list of invasive species rendering them poor in both diversity 

and productivity (see Chapter 3, for current management). 

15. Conservation Priorities and Initiatives 

The Service is actively involved in the development and 

implementation of a number of conservation plans for migratory bird 

species, including the North American Waterfowl Management Plan 

(USFWS et al. 1986, 1998), Central Valley Joint Venture 

Implementation Plan (CVJV 2006), Partners in Flight North 

American Landbird Conservation Plan (Rich et al. 2004), Riparian 

Bird Conservation Plan (RHJV 2004), Draft Grassland Bird 

Conservation Plan (CPIF 2000), United States Shorebird 

Conservation Plan (Brown et al. 2001), Southern Pacific Coast 

Regional Shorebird Plan (Hickey et al. 2003), North American 

Waterbird Conservation Management Plan (Kushlan et al. 2002), Tricolored Blackbird Status Update and Management Guidelines (Beedy 

and Hamilton 1997), Pacific Flyway Management Plan: Western 

Management Unit Mourning Dove (Pacific Flyway Council 2003), 

Anadromous Fish Restoration Program, and the California Wildlife 

Action Plan (CDFG 2005c). Regional step-down plans specific to the 

area are discussed in Appendix M. 

22 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Introduction 

16. Wilderness Review 

As part of the CCP process, lands within the boundaries of the 

Sacramento, Delevan, Colusa, and Sutter Refuges were reviewed for 

wilderness suitability (Appendix O). No lands were found suitable for 

designation as Wilderness as defined in the Wilderness Act of 1964. 

Sacramento, Delevan, Colusa, and Sutter Refuges do not contain 

5,000 contiguous roadless acres, nor do the Refuges have any units of 

sufficient size to make their preservation practicable as Wilderness. 

The Refuges’ lands have been substantially affected by humans, 

particularly through agriculture and urban development. As a result 

of the extensive modification of natural habitats and ongoing 

manipulation of natural processes, adopting a wilderness 

management approach for the Refuges would not facilitate the 

restoration of a pristine or pre-settlement condition, which is a goal of 

wilderness designation. 

Pintails, snow and white-fronted geese at Sacramento Refuge (1941) 

USFWS Photo 

Comprehensive Conservation Plan 23 
Chapter 1 

24 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Planning Process 

Chapter 2. The Planning 

Process 

1. Introduction 

This CCP for the Sacramento, Delevan, Colusa, and Sutter Refuges 

is intended to comply with the requirements of the Improvement Act 

and the NEPA. Refuge planning policy guided the process and 

development of the CCP, as outlined in Part 602, Chapters 1, 3, and 4 

of the U.S. Fish and Wildlife Service Manual. 

Service policy, the Improvement Act, and NEPA provide specific 

guidance for the planning process, such as seeking public involvement 

in the preparation of the EA. The development and analysis of 

“reasonable” management alternatives within the EA include a “no 

action” alternative that reflects current conditions and management 

strategies on the Refuges. Management alternatives were developed 

as part of this planning process and can be found in Appendix A: 

Environmental Assessment. 

The planning process for this CCP began in February 2005 with preplanning meetings and coordination. CCP teams were formed. 

Initially, members of the Refuge staff and planning team identified a 

preliminary list of issues, concerns, and opportunities that were 

derived from wildlife and habitat monitoring and field experience 

from the past management and history of the Refuges. Early in the 

process, visitor services, especially hunting, were identified as 

primary issues. This preliminary list was expanded during public 

scoping and then refined and finalized through the planning process 

to generate the vision, goals, objectives, and strategies for the 

Refuges. 

2. The Planning Process 

Part of comprehensive conservation planning includes preparation of 

a NEPA document. Key steps in the CCP planning process (Figure 

3) and the parallel NEPA process include: 

 Preplanning and Team formation 

 Public Scoping 

 Identifying issues, opportunities, and concerns 

 Defining and revising vision statement and Refuge goals 

 Developing and assessing alternatives 

 Identifying the preferred alternative plan 

 Draft CCP and EA 

 Revising draft documents and releasing final CCP 

 Implementing the CCP 

 Monitoring / Feedback (Adaptive Management) 

Comprehensive Conservation Plan 25 
Chapter 2 

Figure 3. The CCP Process. 

3. Planning Hierarchy 

The Service planning hierarchy that determines the direction of the 

goals, objectives and strategies is a natural progression from the 

general to the specific (Figure 4). Described as a linear process, the 

planning hierarchy is, in reality, a multi-dimensional flow that is 

linked by the Refuge purposes, missions, laws, mandates, and other 

statutory requirements (Figure 5). 

In practice, the process of developing vision, goals, and objectives is 

repetitive and dynamic. During the planning process, or as new 

information becomes available, the plan continues to develop. 

Sora 

Photo by Steve Emmons 

26 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Planning Process 

Figure 4. Hierarchical relationship of refuge goals and 

objectives to other aspects of the planning process. 

Fish and Wildlife Service Mission 

a 

Refuge System Mission 

a 

Refuge Purpose(s)* 

a 

National and Regional Goals and Priorities 

a 

Ecosystem Goals and Objectives 

a 

Refuge Vision 

a 

Goals 

a 

Objectives 

a 

Strategies 

a 

Monitoring and Feedback 

(Adaptive Management) 

(*When in conflict, we give priority to Refuge 

purpose(s) over the Refuge System mission.) 

CCP scoping meeting in Yuba City, CA 

Photo by Kipp Morrill 

Comprehensive Conservation Plan 27 
Chapter 2 

Figure 5. Relationships between Service and other planning 

efforts. 

4. The Planning Team 

The CCP process requires close teamwork with the staff, planners, 

and other partners to accomplish the necessary planning steps, tasks, 

and work to generate the CCP document and associated EA. The 

planning team is responsible for the CCP’s content and will ensure 

that, when implemented it will achieve the purposes of the Refuges 

and help fulfill the Refuge System mission. Two teams were formed: 

4.1. Core Team 

The core team is responsible for the initiation and completion of all 

planning steps, including public involvement and NEPA. The 

members are responsible for researching and generating the 

contents of the CCP document and participate in the entire planning 

28 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Planning Process 

process. The team consists of a refuge planner, refuge managers, 

biologists, and visitor services staff for the Complex (Appendix N). 

The core team meets regularly to discuss and work on the various 

steps and sections of the CCP. The team members also work 

independently in producing their respective CCP sections, based on 

their area of expertise. Multi-tasking by team members is a standard 

requirement since work on the CCP occurs in addition to their 

regular workload. 

4.2. Expanded Team 

The expanded team is the advisory and coordination forum of the 

CCP. It is significant for these Refuges because of the history of 

working in close partnership with other local, State, Federal, and 

private agencies and organizations concerned with the Refuges in the 

Complex. The expanded team is composed of the Core team, other 

Service and Federal personnel, and California Department of Fish 

and Game personnel who provide comments, discussion, and 

coordination during the planning process (Appendix N). 

5. Pre-Planning 

Pre-Planning involved forming the planning teams, developing the 

CCP schedule, and gathering data. The team determined procedures, 

work allocations, and outreach strategies. The team also created a 

preliminary mailing list. 

6. Public Involvement in Planning 

Public involvement is an important and necessary component of the 

planning process. Public scoping meetings allow the Service to 

provide updated information about the Refuge System and the 

Refuges. Most important, these meetings allow the refuge staff to 

hear public comments, concerns, and opportunities. These public 

meetings provide valuable discussions and identify important issues 

regarding the Refuge and the surrounding region. 

The Service hosted public meetings in Willows, Colusa, and Yuba 

City, California in July 2005 (Table 1). Each meeting began with a 

presentation introducing the Refuges, provided an open forum for 

public comment, and ended with a breakout session consisting of 

various tables with refuge staff and information available to address 

questions regarding Refuge management, wildlife and habitat, and 

visitor services. In addition to comments made by participants and 

noted on flip charts at the meetings, comments were also received by 

written comment cards, email, faxes, and letters. These comments 

were analyzed and used to further identify Refuge issues and revise 

CCP goals, objectives, and strategies (Table 2). 

Comprehensive Conservation Plan 29 
Chapter 2 

Table 1. Public Scoping Meetings. 

Meeting Date Location Attendance 

July 6, 2005 Willows, CA 9 

July 12, 2005 Colusa, CA 13 

July 14, 2005 Yuba City, CA 13 

Table 2. Refuge Issues Identified Through Public Comment. 

Refuge Issue Category Number of 

Comments 

Received (1) 

Percentage of 

Total Comments 

Visitor Services 64 49% 

Hunting 55 40% 

Fishing 3 2% 

Environmental 

Education/Outreach 

2 2% 

Other Visitor Services 4 3% 

Wildlife & Habitat 21 16% 

Refuge Management 22 17% 

Continue Current 

Management 

3 2% 

Water Supply 3 2% 

Refuge Management 12 10% 

LE/Fire 4 3% 

Flooding Issues 11 8% 

Other Comments 13 10% 

Total Comments (Total 

Number of 

People/Organizations 

Commenting) 

131 (46) 

1

 Total number of comments received is greater than the total 

number of people commenting since each of the letters, emails, faxes, 

comments cards, and flipchart comments received may contain more 

than one comment. 

30 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Planning Process 

7. Public Outreach 

During the planning process, Refuge staff continued to actively 

participate with the various working groups and agency teams 

concerning the Complex. The staff also met with several special 

interest and local groups to explain the planning process and to listen 

to their concerns. 

An information letter called a “Planning Update” was also mailed to 

the public. These periodic publications were created to provide the 

public with up-to-date Refuge information and progress on the CCP 

process. The Planning Updates were also made available on the 

Complex’s webpage, in the visitor center, and at various outreach 

meetings. The EA (Appendix A) contains a list of individuals and 

organizations that were notified or were sent a copy of the Draft 

CCP, were sent planning updates, or attended scoping meetings. 

8. Issues, Concerns, and Opportunities 

Through the scoping process and team discussions, the planning team 

identified issues, concerns, and opportunities. Thirty-five people 

attended the three public scoping sessions held in July 2005. Fortysix people/organizations provided 131 comments as of September 

2005 (Table 2) for consideration in identifying issues and 

opportunities for the CCP. The team categorized the comments into 

five main areas of interest: visitor services, wildlife and habitat, 

refuge management, flooding issues, and other comments. Visitor 

services received the most comments (49 percent) followed by refuge 

management (17 percent), wildlife and habitat (16 percent), other 

comments (10 percent), and flooding issues (8 percent). 

Of the sixty-four comments regarding visitor services, fifty-five were 

about hunting. Many of the hunting comments urged the Service to 

maximize the quantity and quality of hunting opportunities on the 

Refuges. Some of these comments were very specific regarding how 

the Refuges should change the hunting program, while others were 

more general. Two comments stated hunting should not be allowed on 

the Refuges and three stated fishing should be allowed on the 

Refuges. There were two comments about environmental education 

and outreach, and four about other visitor services. 

The Refuge management category received twenty-two comments. 

Three comments suggested that the Refuges continue with their 

current management. Three comments expressed concern about 

water supply for the Refuges and two comments expressed the need 

for more law enforcement. One comment requested more prescribed 

burning on the Refuges; however, one comment stated that the 

prescribed burning program should be eliminated. Twelve other 

comments were made ranging from assessing the impacts of 

recreation on native flora and fauna to expanding the Refuges. 

Comprehensive Conservation Plan 31 
Chapter 2 

CCP scoping meeting in Yuba City, CA 

Photo by Kipp Morrill 

Twenty-one comments regarding wildlife and habitat issues were 

received. Several of the comments suggested increasing the 

waterfowl production on the Refuges by providing more breeding 

habitat in the closed areas. Several other comments expressed 

concern with the declining pheasant numbers both on and off of the 

Refuges. Several comments suggested leaving remnant stands of 

cover in treated management units. 

Sutter Refuge was the focus of the eleven flood-related comments. 

Approximately 80 percent of the Refuge is located within the Sutter 

Bypass. Sutter Bypass was built in the 1920s and is a dedicated flood 

control channel. The concern expressed in the comments dealt with 

the management of the vegetation on the Refuge. There was 

apprehension that this vegetation may obstruct floodwater flows and 

provide a safety concern to properties in Sutter, Colusa, and Yolo 

counties. 

The thirteen comments in the other comments category ranged from 

suggesting that the Sacramento River Conservation Area Forum 

landowner assurances policy be incorporated in the CCP to specific 

topics to be covered in the CCP. Several comments suggested 

referring to different plans and surveys for more information. 

9. Development of the Refuge Vision 

A vision statement is developed for each refuge or complex as part of 

the CCP process. Vision statements are grounded in the unifying 

mission of the Refuge System and describe the desired future 

conditions of the refuge unit in the long term (more than 15 years). 

They are based on the refuge’s specific purposes, the resources 

present on the refuge, and any other relevant mandates. Please refer 

to Chapter 1 for the Refuges’ vision statement. 

32 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Planning Process 

10. Determining the Refuge Goals, Objectives, and Strategies 

The purpose for creating the Refuges is established by law (Chapter 

1, Section 11.1-11.4). The Improvement Act directs that the planning 

effort develop and revise the management focus of the Refuge within 

the Service’s planning framework, which includes: the Service 

mission, the Refuge System mission, ecosystem guidelines, and 

refuge purposes. This is accomplished during the CCP process 

through the development of goals, objectives, and strategies. 

10.1. Goals 

The Service defines a goal as a “descriptive, open-ended, and often 

broad statement of desired future conditions that conveys a purpose, 

but does not define measurable units” (602 FW 1 of the Service 

Manual). Refuge goals are a means to achieving refuge purposes. 

Goals translate to one or more objectives that define these conditions 

in measurable terms. A well-written goal directs work toward 

achieving a refuge’s vision and ultimately the purpose(s) of a refuge. 

Collectively, a set of goals is a framework within which to make 

decisions. 

10.2. Interim Refuge Goals 

The interim goals for Sacramento, Delevan, Colusa, and Sutter 

Refuges (from 1996 Interim Goals) are: 

 Provide habitat for migratory birds, particularly waterfowl 

and other water birds. 

 Provide habitat for and management of endangered, 

threatened, or species of special concern. 

 Protect and provide habitat for Neotropical migratory birds. 

 Preserve a natural diversity and abundance of flora and 

fauna. 

 Provide opportunities for the understanding and appreciation 

of wildlife ecology and the human role in the environment and 

provide high-quality wildlife-dependent recreation and 

education. 

 Conduct and direct compatible, management-oriented 

research. 

 Alleviate crop depredation. 

Through the CCP process these interim goals were evaluated and 

revised and are detailed in Chapter 4. 

10.3. Objectives, Rationale, and Strategies 

Once the Refuge goals are reviewed and revised then various 

objectives, a rationale, and strategies are determined to accomplish 

each of the goals. 

Objectives: The Service defines objectives as “a concise statement of 

what we want to achieve, how much we want to achieve, when and 

where we want to achieve it, and who is responsible for the work” 

(602 FW 1 of the Service Manual). Objectives are incremental steps 

Comprehensive Conservation Plan 33 
Chapter 2 

we take to achieve a goal. They are derived from goals and provide a 

foundation for determining strategies, monitoring refuge 

accomplishments, and evaluating success. The number of objectives 

per goal will vary. Where there are many, an implementation 

schedule may be developed. All objectives must possess the following 

five properties: specific, measurable, achievable, results-oriented, and 

time-fixed. 

Rationale: Each objective should document the rationale for forming 

the objective. The degree of documentation will vary, but at a 

minimum, it should include logic, assumptions, and sources of 

information. This promotes informed debate on the objective’s 

merits, provides continuity in management through staff turnover, 

and allows reevaluation of the objective as new information becomes 

available. 

Strategy: The Service defines a strategy as “a specific action, tool, 

technique, or combination of actions, tools, and techniques used to 

meet unit objectives” (602 FW 1 of the Service Manual). Multiple 

strategies can be used to support an objective. 

Yellow warbler 

Photo by Steve Emmons 

34 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Planning Process 

11. Development of the Refuge Management Alternatives 

Alternatives are “different sets of objectives and strategies or means 

of achieving refuge purposes and goals, helping to fulfill the Refuge 

System mission, and resolving issues” (602 FW 1 of the Service 

Manual). The development of alternatives, assessment of their 

environmental effects, and identification of the preferred 

management alternative are fully described in the EA (Appendix A). 

Alternatives were developed to represent reasonable options that 

address the specific Refuge issues and challenges. A “no action” or 

continuation of current management alternative is required by 

NEPA. A range of other alternatives was studied and are described 

in the EA (Appendix A). The alternatives are summarized below. 

11.1. Alternative A: No Action 

Under the Alternative A: No Action, the Refuges would continue to 

be managed as it has in the recent past. Recent management has 

followed existing step-down management plans: 

 Annual Habitat Management Plans for Sacramento, Delevan, 

Colusa, and Sutter National Wildlife Refuges 

 Fire Management Plan for Sacramento National Wildlife Refuge 

Complex 

 Integrated Pest Management for Mosquito Control on 

Sacramento National Wildlife Refuge Complex 

 Safety Plan 

 Continuity of Operations Plan 

 Hazardous Tree Removal Plan 

The focus of the Refuges would remain the same: to provide habitat 

and maintain current active management practices and continue to 

manage and provide habitat for threatened and endangered species, 

migratory and resident birds, and other wildlife. The Refuges would 

continue to offer wildlife-dependant recreation opportunities 

including hunting, wildlife observation, photography, environmental 

education, and interpretation. Current staffing and funding levels 

would remain the same. 

11.2. Alternative B: Emphasize Biological Resources 

Under this alternative, the Refuges would emphasize management 

for biological resources. Biological opportunities would be maximized 

to allow optimum wildlife and habitat management throughout the 

majority of the Refuges. In addition, staffing and funding levels 

would need to be redirected and increased substantially to implement 

this alternative. 

11.3. Alternative C: Proposed Action 

Alternative C would achieve an optimal balance of biological resource 

objectives and visitor services opportunities. Habitat management 

and associated biological resource monitoring would be improved. 

Visitor service opportunities would focus on quality wildlifeComprehensive Conservation Plan 35 
Chapter 2 

dependant recreation distributed throughout the Refuges. Staffing 

and funding levels would need to be increased to fully implement this 

alternative. 

11.4. Alternative D: Emphasize Visitor Services 

Under Alternative D, the Refuges would emphasize management for 

visitor services. Wildlife-dependant recreational opportunities would 

be expanded on the Refuges. However, staffing and funding levels 

would need to be redirected and increased substantially to implement 

this alternative. 

12. Selection of the Proposed Action 

The alternatives were analyzed in the EA (Appendix A) to determine 

their effects on the Refuges environment. Based on this analysis, the 

Service has selected Alternative C as the proposed action because it 

best achieves the Refuges goals and purposes, as well as Refuge 

System and Service missions. 

Alternative C is founded upon the existing cooperative management 

programs, with enhancements in habitat and monitoring programs 

and an integration of a visitor services program that includes hunting, 

wildlife observation, photography, environmental education, and 

interpretation. Cooperative management refers to the current 

practice of working closely with State and other partners to provide 

protected and enhanced habitat along with visitor service 

opportunities on publicly owned properties. Please refer to Chapter 

4, which describes this proposed management plan. 

13. Plan Implementation 

This Draft CCP and EA will be provided for public review and 

comment. Comments received by the Service will be incorporated 

where appropriate and perhaps result in modifications to the 

preferred alternative or selection of one of the other alternatives. 

The alternative that is ultimately selected will become the basis of 

the ensuing Final CCP. This document then becomes the basis 

for guiding management over the coming 15-year period. It will 

guide the development of more detailed step-down management 

plans for specific resource areas and will also underpin the annual 

budgeting process for refuge operations and maintenance 

(Chapter 5). Most importantly, it lays out the general approach to 

managing habitat, wildlife, and people at the Sacramento, 

Delevan, Colusa, and Sutter Refuges that will direct day-to-day 

decision-making and actions. 

A review of the CCP will take place approximately every five 

years and the CCP will be updated every fifteen years. 

Ash-throated flycatcher 

Photo by Steve Emmons 

36 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Chapter 3. The Refuge 

Environment 

1. Refuge Descriptions 

1.1. Sacramento Refuge 

Sacramento Refuge is the headquarters of the Complex and is located 

in the Sacramento Valley of north-central California. The Refuge is 

situated about 90 miles north of the metropolitan area of Sacramento 

and six miles south of the town of Willows, population 6,000. The 

Refuge consists of 10,819 acres in Glenn and Colusa counties. 

The Refuge was established as a refuge for migratory birds and other 

wildlife. Major objectives are to: provide feeding and resting habitat 

for wintering waterfowl; provide habitat and manage for endangered, 

threatened, or sensitive species of concern; preserve a natural 

diversity and abundance of flora and fauna; provide an area for 

compatible, management-oriented research; alleviate crop 

depredation; and provide visitor service activities such as hunting, 

wildlife observation, photography, environmental education, and 

interpretation. 

The Refuge is divided into approximately 117 management units, and 

managed wetlands comprise about 65 percent of the total acreage. 

They consist of summer wetlands (permanent and semi-permanent 

wetlands) and seasonally flooded wetlands (irrigated and nonirrigated seasonally flooded wetlands). The remaining acreage is 

comprised of unmanaged wetlands, alkali meadows, vernal pools, 

grasslands, riparian forests, and other habitats. 

The wetlands of the Central Valley are critical to waterfowl of the 

Pacific Flyway (USFWS and Canadian Wildlife Service 1986). 

Currently, about 44 percent of the Pacific Flyway’s waterfowl winters 

in the Sacramento Valley. The Refuge typically supports wintering 

waterfowl in excess of 680,000 ducks and 178,000 geese. As wetlands 

of the Central Valley have been lost, the waterfowl resource has 

become increasingly dependent upon the refuges of the Sacramento 

Valley. To help support the abundance of waterfowl and other 

wetland-dependent wildlife, the Complex’s habitat management 

program is one of the most intensive in the Refuge System. 

In addition to wintering waterfowl and associated resident, migratory 

and breeding wildlife species, habitats of the Sacramento Refuge 

support eight federally-listed threatened, endangered, or candidate 

species. Sacramento Refuge is identified as a core area, with the 

highest level of habitat protection–Priority 1–necessary for recovery 

of vernal pool plant and animal species (USFWS 2005a). This is not 

Comprehensive Conservation Plan 37 
Chapter 3 

surprising since some of the units at the Refuge form the largest, 

relatively intact remnants of vernal pool and vernal pool-alkali 

meadow complexes in the Colusa Basin. Priority 1 identifies localities 

or species, which represent the rarest species/genetics, most unique 

environmental/habitat conditions, and greatest threat of destruction 

(USFWS 2005a). Priority levels ensure that Federal, State and local 

agencies, which manage land, use their authorities to protect habitat 

and provide for the recovery and conservation of species identified in 

the recovery plan (USFWS 2005a). The recovery plan lists various 

conservation planning tools and programs, which minimize and avoid 

habitat loss, while others provide habitat and species occurrence 

conservation incentives (USFWS 2005a). 

The visitor services program offers a six-mile auto tour; a two-mile 

walking trail; environmental education activities, presentations, 

guided tours, videos/DVDs, bookstore, and wildlife exhibits at the 

visitor center; interpretive kiosks with brochures; two photography 

blinds; teacher assistance; volunteer program; and 

waterfowl/pheasant hunting. The visitor center, six-mile auto tour 

route, two-mile walking trail, and two photo blinds accommodate 

more than 86,000 annual visits. Waterfowl, coot, common moorhen, 

snipe, and pheasant hunting are permitted on Saturdays, Sundays, 

and Wednesdays and account for about 7,600 visits annually. 

1.2. Delevan Refuge 

Delevan Refuge is situated about 80 miles north of the metropolitan 

area of Sacramento and four miles east of the town of Maxwell, 

population 1,500. The Refuge consists of 5,877 acres in Colusa 

County. 

Delevan Refuge was established in 1962 as a refuge and breeding 

ground for migratory birds and other wildlife. Major objectives are to 

provide feeding and resting habitat for wintering waterfowl; provide 

habitat and manage for endangered, threatened, or sensitive species 

of concern; preserve a natural diversity and abundance of flora and 

fauna; alleviate crop depredation; and provide visitor service 

activities such as hunting and wildlife observation. 

Delevan Refuge is divided into approximately 67 management units, 

and managed wetlands comprise about 78 percent of the total 

acreage. They consist of summer wetlands and seasonally flooded 

wetlands. The remaining acreage is comprised of unmanaged 

wetlands, alkali meadows, vernal pools, grasslands, riparian forest, 

and other habitats. The Refuge typically supports wintering 

waterfowl in excess of 415,000 ducks and 150,000 geese. 

The Refuge supports one of the largest known populations of 

palmate-bracted birds-beak (Federal-listed endangered species) and 

significant breeding colonies of tricolored blackbirds. Some of the 

units on the Refuge form one of the largest relatively intact remnants 

38 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

of the vernal pool and vernal pool-alkali meadow habitats that remain 

in the Colusa Basin. 

A limited visitor services program offers wildlife observation and 

photography from adjacent county roads, including an undeveloped 

Watchable Wildlife site on Maxwell Road adjacent to the Refuge’s 

south boundary. Waterfowl, coot, common moorhen, snipe, and 

pheasant hunting are permitted on Saturdays, Sundays, and 

Wednesdays and account for about 6,900 visits annually. 

White geese flying 

Photo by Mike Peters 

1.3. Colusa Refuge 

Colusa Refuge is situated about 70 miles north of the metropolitan 

area of Sacramento and one mile southwest of the town of Colusa, 

population 5,500. The Refuge consists of 4,686 acres in Colusa 

County. 

Colusa Refuge was established in 1945 as a refuge and breeding 

ground for migratory birds and other wildlife and to reduce damage 

of agricultural crops caused by waterfowl. Major objectives are to 

provide feeding and resting habitat for wintering waterfowl; provide 

habitat and manage for endangered, threatened, or species of 

concern; preserve a natural diversity and abundance of flora and 

fauna; alleviate crop depredation; and provide visitor service 

activities such as hunting, wildlife observation, photography, 

environmental education, and interpretation. 

Colusa Refuge is divided into approximately 59 management units, 

and managed wetlands comprise about 71 percent of the total 

acreage. They consist of summer wetlands and seasonally flooded 

wetlands. The remaining acreage is comprised of unmanaged 

wetlands, alkali meadows, vernal pools, grasslands, riparian, and 

other upland habitats. The Refuge typically supports wintering 

waterfowl in excess of 218,000 ducks and 113,500 geese. 

Comprehensive Conservation Plan 39 
Chapter 3 

The Refuge supports one of the largest known populations of giant 

garter snakes (Federal-listed threatened species) and palmatebracted birds-beak (Federal-listed endangered species). Some of the 

units on the Refuge form one of the largest, relatively intact 

remnants of the vernal pool and vernal pool-alkali meadow habitats 

that remain in the Colusa Basin. 

The visitor services program offers wildlife observation and 

photography from a three-mile auto tour route, one-mile walking 

trail, and one photography blind that supports 16,300 annual visits. 

Waterfowl, coot, common moorhen, snipe, and pheasant hunting are 

permitted on Saturdays, Sundays, and Wednesdays and account for 

about 3,700 visits per year. 

1.4. Sutter Refuge 

Sutter Refuge is situated about 50 miles north of the metropolitan 

area of Sacramento, 10 miles southwest of Yuba City, population 

approximately 60,000, and five miles south of Sutter, population 

approximately 2,900. The Refuge consists of 2,591 acres in Sutter 

County. 

The majority of the Refuge is located within the Sutter Bypass of the 

Sacramento River Flood Control Project; an area dedicated to flood 

water conveyance. The eastern levee of the Sutter Bypass is managed 

by the Department of Water Resources. The western levee is 

managed by Reclamation District 1660. Both levees are part of the 

Sutter Bypass Wildlife Area managed by the California Department 

of Fish and Game (CDFG). The State of California Reclamation 

Board holds easements within the Bypass portion of the Refuge. The 

easements allow for the flow of floodwaters over the land and the 

removal of vegetation that may be impeding floodwaters. Copies of 

the specific easements are available for review at the Refuge 

Headquarters. 

Sutter Refuge was established in 1945 as a refuge and breeding 

ground for migratory birds and other wildlife and to reduce damage 

of agricultural crops caused by waterfowl. Major objectives are to: 

provide feeding and resting habitat for wintering waterfowl; provide 

habitat and manage for endangered, threatened, or species of 

concern; preserve a natural diversity and abundance of flora and 

fauna; alleviate crop depredation; and provide visitor service 

activities, such as hunting and wildlife observation. 

Sutter Refuge is divided into approximately 27 management units, 

and managed wetlands comprise about 73 percent of the total 

acreage. They consist of summer wetlands and seasonally flooded 

wetlands. The giant garter snake (Federal-listed threatened species) 

occurs on the Refuge primarily in the portion outside the Bypass. In 

recent years, the Refuge has supported significant white-faced ibis 

40 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

The Refuge Environment 

nesting colonies (5,000-15,000 birds). The Refuge typically supports 

wintering waterfowl in excess of 73,000 ducks and 100,000 geese. 

The remaining acres are in unmanaged wetlands, grasslands, riparian 

forest, and other habitats. The riparian habitat provides habitat for a 

variety of migratory songbirds, including the western yellow-billed 

cuckoo (Federal candidate species, State-listed threatened species), 

nesting Swainson’s hawks (State-listed species), and nesting 

rookeries for great blue herons and great egrets. 

A limited visitor service program offers hunting for waterfowl, coot, 

common moorhen, snipe, and pheasant on Saturdays, Sundays, and 

Wednesdays and account for approximately 2,100 visits annually. 

2. Geographic/Ecosystem Setting 

In the 1850s and 1860s, the area southeast of Willows, west of 

Princeton, and north of Colusa (known as the Colusa Plains) was 

characterized by alkali soil and sparse vegetation (Hinds 1952). These 

areas were dry most of the year or sometimes for whole seasons, but 

during major floods, were inundated and formed shallow lakes. 

Before reclamation occurred along the river, about 60 percent of the 

Sacramento Valley was subject to overflow, including basins, river 

lands, and a considerable portion of 

the low plains. The alkali plain was 

dotted with vernal pools and lakes of 

all sizes. These natural intermittent 

wetlands provided feeding and 

roosting habitat for many waterfowl. 

Except for a few willow trees at a 

watering hole near “the Willows,” the 

area was characterized as an open, 

wind-swept, alkali plain that 

presented an almost unbearable 

combination of summer heat and 

drought and unpredictable winter 

flooding. 

Constructing delivery ditches at Sacramento Refuge (1938) 

USFWS Photo 

Winter wheat was introduced to the plains in the 1870s. Native 

pasture and winter wheat provided prime winter and early spring 

forage habitat for hundreds of thousands of small Canada geese. 

These early farmers employed “goose herders” to haze geese off their 

lands and keep them from devastating crops. The development of 

irrigation systems brought rice agriculture to the Sacramento Valley 

in the 1910s. Artesian wells were dug and surface water was diverted 

from the Sacramento River. The conversion to rice attracted an 

additional abundance of waterfowl to the plains and also resulted in 

Comprehensive Conservation Plan 41 
Chapter 3 

increased numbers in late summer and fall months. Coastal wetland 

loss during the same period likely contributed to this shift. Ducks 

were especially problematic for rice farmers, as they fed in the fields 

by the hundreds of thousands just prior to the harvest. Early 

migrating ducks, especially pintails, would often flatten and eat up to 

40 acres of rice in a single night (Neff et al. 1943). 

The United States government purchased the Spalding Ranch in 1937 

because it was “the most famous goose sanctuary on the West Coast.” 

Sacramento Refuge was established to manage land and provide lure 

crops for ducks that depredated neighboring rice fields. The Civilian 

Conservation Corps established Camp Sacramento at the Refuge in 

1937 and began wetland habitat construction that remains an 

important feature of refuge management today (Hall 1975). 

2.1. The Sacramento Valley Ecosystem 

The Sacramento Valley forms the northern portion of the Great 

Central Valley, also referred to as the Central Valley, a 400-mile 

elongated depression that lies between the Coast Ranges and the 

Sierra Nevada (Figure 2). The Central Valley is actually two large 

valleys lying end to end, each drained by a major river. The 

Sacramento Valley is drained southward by the Sacramento River 

and the San Joaquin Valley, which forms the southern portion of the 

Central Valley, is drained northward by the San Joaquin River. The 

confluence of these two rivers occurs in the Delta area, east of San 

Francisco Bay. 

In its pristine state, the Central Valley was characterized by over 25 

plant communities providing habitats for a great diversity of plants 

and animals. These communities consisted of various riparian scrubs, 

forests, woodlands and savannas; perennial grasslands; annual 

wildflower fields; interior dune lands; vernal pools; alkali sinks, 

meadows, and scrubs; and fresh and brackish water marshes. Central 

Valley vegetation and habitats have been altered by human activity 

more than any other geomorphic province. In 1987, a report for the 

California Senate (Airola and Messick 1987) depicted that the valley 

grassland community is more than 99 percent gone, the freshwater 

marsh community is more than 94 percent gone, and the riparian 

woodland is about 89 percent gone. Approximately 75 percent of all 

vernal pools in the Central Valley were lost by 1997 (Holland 1998). 

Early losses were primarily related to conversion to agriculture 

croplands. More recent losses have been a result of conversion of 

historic cattle grazing lands to other uses and widespread 

urbanization (USFWS 2005a). 

Non-native invasive species now dominate many natural vegetation 

types and wildlife habitats throughout the Central Valley. 

Agricultural developments, urban expansion, alteration of hydrologic 

regimes and channelization, and introduced plants and animals have 

42 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

all contributed to the destruction of native habitats (Gilmer et al.1982, 

Katibah 1984). 

In the Central Valley, about 250,000 acres of managed wetlands 

remain, about a third of which are publicly owned. Two-thirds are 

privately owned, mostly waterfowl hunting clubs. About 108,000 acres 

of riparian habitat remain, much of it fragmented (CVJV 2006). A 

major portion of the remaining vernal pool habitat is also privately 

owned. 

Despite the huge loss of wetlands, much of the agricultural 

conversion around the Refuges and in the Sacramento Valley has 

been to rice. While not as productive or diverse as natural or 

managed wetlands, rice is generally wildlife-friendly relative to many 

other crop types (i.e. cotton or other row crops). Waste grain and 

other prey items in rice fields play a major role in the carrying 

capacity of current waterfowl and other waterbirds in the Central 

Valley (CVJV 2006). There is about 500,000 acres of rice in the 

Central Valley; most of it is in the Sacramento Valley and currently, 

about 70 percent is purposely flooded during winter months for 

stubble management and waterfowl hunting (CVJV 2006). Migratory 

birds and a number of other wildlife commonly spend time both on 

Refuges and nearby privately owned rice fields, often on a daily basis. 

3. Physical Environment 

3.1. Climate and Air Quality 

The climate of California’s northern Central Valley is classified as 

Mediterranean, with cool, wet winters and hot, dry summers. The 

annual average precipitation is 16-18 inches. Heavy fog is common 

during the winter months, while thunderstorms, hail, and snow are 

rare occurrences. The mean annual temperature is 61.7°F with 

extremes of 118°F and 15°F. The south winds are associated with 

storms in the winter and cooling trends in the summer. North winds 

are usually dry following winter storms, and hot and dry in the 

summer. 

The Refuges are in California’s Sacramento Valley Air Basin. The 

Sacramento Valley Air Basin encompasses 15,043 square miles 

including Butte, Colusa, Glenn, Sacramento, Shasta, Sutter, Tehama, 

Yolo, and Yuba counties, the western urbanized portion of Placer 

County, and the eastern portion of Solano County. The Glenn County 

Air Pollution Control District, Colusa County Air Pollution Control 

District, and the Sutter County Air Pollution Control District are the 

agencies responsible for ensuring compliance with Federal and State 

air quality standards in the basin where the Refuges are located. 

The Federal and State governments have each established ambient 

air quality standards for several pollutants. Most standards have 

been set to protect public health. However, standards for some 

Comprehensive Conservation Plan 43 
Chapter 3 

pollutants are based on other values, such as protecting crops and 

materials, and avoiding nuisance conditions. Currently, Sutter 

County is federally classified as a non-attainment area for groundlevel ozone. A non-attainment area is defined as any area that does 

not meet ambient air quality standards for a pollutant. In addition, 

Glenn, Colusa, and Sutter counties are classified by the State of 

California as non-attainment areas for ozone and particulate matter 

at the 10-micron level or smaller (PM10) standards. In fact, only 

three counties in the entire State are not classified as non-attainment 

areas for PM10. Classification as a non-attainment area means that 

the State must develop an implementation plan to outline methods for 

reaching identified air quality standards. Permitting, scheduling, and 

restrictions on some activities may be required. Currently, individual 

counties require smoke management plans and limit acreage burned 

on prescribed burns conducted by the Complex. 

Ozone, the main component of photochemical smog, is 

formed through a complex series of chemical 

reactions between reactive organic gasses (ROG) and 

nitrogen oxides (NOx). On-road motor vehicles and 

other mobile sources are the largest contributors to 

NOx emissions in the Sacramento Valley. On-road 

motor vehicles, area-wide sources, and stationary 

sources are significant contributors to ROG 

emissions. Once formed, ozone remains in the 

atmosphere for 1 or 2 days. As a result, ozone is a 

regional pollutant and often impacts a large area. 

Ozone’s main effects include damage to vegetation, 

chemical deterioration of various materials, and 

irritation and damage to the human respiratory 

system. 

Red-tailed hawk 

Photo by Steve Emmons 

PM10 is produced by stationary point sources such as fuel 

combustion and industrial processes; fugitive sources, such as 

roadway dust from paved and unpaved roads; wind erosion from open 

land; and transportation sources, such as automobiles. The primary 

sources of PM10 in the Sacramento Valley are fugitive dust from 

paved and unpaved roads and agricultural operations, and smoke 

from residential wood combustion and seasonal agricultural burning. 

Soil type and soil moisture content are important factors in PM10 

emissions. Federal and State PM10 standards are designed to 

prevent respiratory disease and protect visibility. 

Certain land uses are considered more sensitive to air pollution than 

others. Locations, such as schools, hospitals, and convalescent homes, 

are labeled sensitive receptors because their occupants are more 

susceptible to respiratory infections and other air quality-related 

44 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

The Refuge Environment 

health problems than the general public. Residential areas are also 

considered to be sensitive receptors because residents tend to be 

home for extended periods of time, resulting in sustained exposure to 

any pollutants present. 

3.2. Water Supply 

There are two main water sources used to manage the Sacramento, 

Delevan, Colusa, and Sutter Refuges’ wetland habitat base. The 

majority of the water used throughout the year is delivered from the 

Sacramento River from the Bureau of Reclamation’s (BOR) Central 

Valley Project (CVP). In addition, there are some riparian water 

rights that allow a refuge to divert specific amounts of water from 

creeks and tributaries during certain times of the year. There has 

been very little use of ground water on the Refuges, other than 

domestic wells. All water sources depend largely upon gravity flow 

and are distributed and impounded via a series of delivery and 

drainage ditches, levees, and water control structures. 

The water supply is probably best described in relation to the Central 

Valley Project Improvement Act (CVPIA), which instituted major 

changes to the Refuges’ water supply. 

In October of 1992, the CVPIA (Public Law 102-575) was passed into 

law. The purposes of the Act include addressing the impacts of the 

CVP on fish, wildlife and associated habitats. The Act directed that 

water, in amounts equal to the Level 2 and increasing to the Level 4 

water supplies identified in the “Report on Refuge Water Supply 

Investigations,” be made available year-round to refuges in 

California’s Central Valley (BOR 1989). Level 2 is the firm water 

supply historically required for existing habitat management, while 

Level 4 is the increased amount of water needed for full habitat 

development. These amounts are described in Table 3. The increased 

volume between Level 2 and Level 4 supplies was to come from 

annual increases, in 10 percent increments, until Level 4 supplies 

were reached (CVPIA, Title 34 Public Law 102-575). While these 

water amounts are allotted by refuge and totaled by month, the Act 

allows for water redistribution both between months and among 

refuges, in order to respond to specific annual habitat management 

program needs. 

Table 3. CVPIA Water Supplies for each of the Refuges. 

Refuge Level 2 (acre feet) With Level 4 

(acre feet) 

Sacramento 46,400 50,000 

Delevan 21,950 30,000 

Colusa 25,000 25,000 

Sutter 23,500 30,000 

Comprehensive Conservation Plan 45 
Chapter 3 

3.2.1. Pre - CVPIA 

Prior to October 1992, the Complex had no firm water supply. Water 

was provided to Sacramento, Delevan, and Colusa Refuges by BOR, 

via facilities of the Glenn-Colusa Irrigation District (GCID), on an “as 

available” basis. While most years saw adequate amounts delivered, 

the Refuges often suffered from lack of water availability from late 

November through early April, as GCID shut down for canal 

maintenance. Absent adequate rainfall, many Refuge wetlands would 

begin to go dry in early December. In the mid-1980's, BOR began 

construction of a cross-tie from Stony Creek to the Tehama-Colusa 

Canal to divert 80 cubic feet per second (cfs) to meet water contract 

demands from other irrigation districts. The Sacramento Refuge was 

promised utilization of any or all of this 80 cfs pending other current 

requests. The endangered listing of the winter-run Chinook salmon in 

the Sacramento River shut down any water deliveries via the 

Tehama-Colusa Canal, thereby eliminating any possibilities for 

winter water for the Refuges. 

Additional problems involving endangered Chinook salmon existed at 

the point of water diversion. GCID diverts water from the 

Sacramento River via lift pumps near Hamilton City at a time when 

emigrating salmon fry could be impacted by an unscreened or poorly 

screened diversion. As a result, in the late 1980s and early 1990s, 

GCID completed extensive work to improve the efficiency of their 

fish screens at the Hamilton City pumping plant. 

On their return migration, adult salmon 

also encounter problems resulting from 

the redistributed nature of Valley water 

supplies derived from the Sacramento 

River. Salmon mistakenly enter the 

Colusa Basin Drain (2047) at its point of 

contact with the Sacramento River near 

Knights Landing, and proceed up the 

many tributaries in search of their 

spawning areas. As a result, each fall 

these “lost salmon” are observed in the 

Refuge portions of creeks and ditches 

that eventually lead to the Colusa Basin 

Drain. 

Northern shoveler 

Photo by Mike Peters 

Sacramento Refuge 

Historically, the Sacramento Refuge had a contract with GCID for 

gravity flow delivery of up to 50,000 acre-feet of BOR CVP water. 

Allowing for a 20 percent conveyance loss, the actual amount of CVP 

water that was available to the Refuge was 37,000 acre-feet annually. 

In addition to this delivered water supply, the Sacramento Refuge 

46 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

also had four appropriative licenses to divert a total of 60 cfs for 

irrigation and/or wildlife purposes on 4,575 acres. Two ground water 

wells were located along the northwest boundary, of which one 

continues to be available, if needed. 

Delevan Refuge 

Other than the gravity flow of delivered surface water, Delevan 

Refuge has no additional sources of water. 

Colusa Refuge 

Colusa Refuge utilized three lift pumps to secure GCID water from 

the Colusa Basin Drain, and one lift pump to utilize water delivered 

by GCID. In addition, the Refuge employed riparian licenses to 

supply up to 25-30 percent of the surface water used during an annual 

habitat management cycle. One groundwater well, located along the 

west boundary at the northwest corner of Tract 10, was used 

sparingly to supplement the water supply in the main canal. 

Sutter Refuge 

The Refuge has two appropriative licenses to divert water for 

irrigation and wetland purposes. They allowed diversion of 25 cfs and 

5 cfs from the east Bypass channel and the water was utilized to 

supply habitat needs on Refuge lands inside the Sutter Bypass. 

Approximately 335 acres of wetland habitat is located outside of the 

Sutter Bypass. An agreement with the Sutter Extension Water 

District provided water for this area via gravity and a low-lift pump 

adjacent to Tract 20. 

3.2.2. Post - CVPIA 

Many of the uncertainties related to the water supply for 

Sacramento, Delevan, and Colusa Refuges were eliminated with the 

authorization of the CVPIA. Not only was a firm water supply 

created, the annual Level 2 allotments can not be decreased by more 

than 25 percent, even during drought (“critically dry”) years. In 

addition, the Act required BOR to pay for the water, deliver it to the 

Refuge boundary, and the water was to be made available yearround. In order to accomplish this, BOR entered into a long-term 

contract with GCID for water delivery to Sacramento, Delevan, and 

Colusa Refuges. 

Each year the Complex provides BOR with the anticipated water 

needs. Since CVPIA’s authorization, only Level 2 water has been 

used on Sacramento and Colusa Refuges. On Delevan Refuge, some 

Level 4 water has been required to meet habitat management 

objectives. Based on experience, the Refuges continued to modify the 

amount, timing, and delivery points of anticipated water needs. To 

date, no CVPIA water has been delivered to Sutter Refuge, primarily 

due to the lack of a means for conveyance. 

Comprehensive Conservation Plan 47 
Chapter 3 

Sutter Refuge uses 1933 Funds (CVPIA) to pay for all water and 

pumping expenses annually (approximately $10,000 for 335 acres). 

In order to implement CVPIA, many improvements have been made, 

including modifications to GCID facilities that allowed year-round 

Refuge water delivery to begin in 2000. 

A series of meters were installed on all three Refuges to measure the 

amounts of water delivered. 

As required by the CVPIA, Water Management Plans were 

completed for Sacramento, Delevan, and Colusa Refuges in 2005 

(Appendix I). These five-year plans document water use, identify 

water supply system needs, and outline steps required to improve 

both the efficiency and quantity of water used. 

3.3. Contaminants and Water Quality 

As environmental awareness grew, impacts to water quality became a 

major focus throughout the United States. In California, probably 

nowhere was this more evident than in the San Joaquin Valley, 

especially with selenium concerns at Kesterson 

Refuge. 

In the Sacramento Valley, due to the lack of a 

secure water supply, Refuges often utilized drain 

water from surrounding agricultural and urban 

lands to flood and maintain wetland habitats. Even 

delivered water from local irrigation districts had 

often previously been used “upstream,” most 

commonly for growing rice. 

Pied-billed grebe and chick 

Photo by Mike Peters 

The California Department of Fish and Game (CDFG) initiated a 

selenium verification study in 1985 (White et al. 1987). They 

concluded that selenium concentrations in water and fish occurred at 

less than harmful levels in the Sacramento Valley. Fish kills in the 

Colusa Basin Drain during the early 1980’s indicated high 

concentrations of molinate and the herbicide thiobencarb (associated 

with rice farming practices) in fish and water samples collected 

throughout the agricultural drains and in the Sacramento River 

downstream of drain inflow. California’s Department of Pesticide 

Regulation implemented the Rice Pesticide Program in 1983, which 

established performance goals for molinate and thiobencarb in 1990 

and the insecticides methyl parathion and malathion beginning in 

1991. County agricultural commissioners, with the use of restricted 

materials permits, implemented program requirements for molinate, 

thiobencarb, methyl parathion, and malathion in 2001. 

48 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Water quality and potential contaminants were also a concern on the 

Complex. To further address these concerns, a collaborative study 

was conducted by the U.S. Geological Survey, U.S. Fish and Wildlife 

Service, and U.S. Bureau of Reclamation entitled “Reconnaissance 

Investigation of Water Quality, Bottom Sediment, and Biota 

Associated with Irrigation Drainage in the Sacramento National 

Wildlife Refuge Complex, California, 1988-89” (Dileanis et al. 1992). 

The report concluded, “there is some degradation of water quality 

related to agricultural drainage in the region, and elevated 

concentrations of some chemical constituents were detected in water, 

sediment, and biological samples. These elevated concentrations were 

only slightly greater than Service guidelines for possible effects on 

wildlife.” Of greatest interest were the DDT family of organochlorine 

compounds detected in all bottom-sediment samples from canals 

containing drain water; the DDE content of white-faced ibis and 

black-crowned night herons (Colusa Refuge); and the thiocarbamate 

herbicide molinate (rice field use) that was detected in all 21 samples 

(one exceeding the State of California guideline for the protection of 

aquatic habitat) timed to coincide with peak spring water releases. 

In addition, a number of ground water wells, both those already in 

existence in the 1980s (especially at Sutter Refuge) and BOR 

exploratory test wells completed in the early 1990s (Sacramento 

Refuge), documented water contamination with arsenic, cadmium, 

mercury, and boron exceeding recommended limits. 

Beginning in 2005 the Complex began membership/participation in 

two groups (Colusa Basin Subwatershed Program and Butte-YubaSutter Water Quality Coalition) of the Sacramento Valley Water 

Quality Coalition. These groups provide water quality monitoring 

required by the Central Valley Regional Water Quality Control 

Board’s Irrigated Lands Conditional Waiver Program. The program 

requires anyone owning lands that have irrigation return water 

and/or storm water runoff leaving their lands to complete water 

quality monitoring. To date, no water quality problems related to the 

Refuges have been documented. 

Most recently, in early 2006, methyl mercury associated with 

seasonal wetlands has become an increased concern. 

3.4. Geology, Hydrology, and Soils 

The area between Willows and Knights Landing is underlain by 

sedimentary and volcanic deposits associated with the Tehama, 

Tuscan, Red Bluff, and Riverbank formations. On top of these 

formations lie younger fan deposits of the Modesto formation, as well 

as basin, marsh, and floodplain alluvial deposits associated with the 

Sacramento River and North Coast Range streams (Harwood and 

Helley 1982; Helley and Harwood 1985). 

Comprehensive Conservation Plan 49 
Chapter 3 

Sacramento, Delevan, and Colusa Refuges are located in the Colusa 

Basin. Over 75 percent of these Colusa Basin refuges occur on basin 

deposits. Here Refuge soils are located at the higher elevations of the 

basin (i.e., the basin rim) where they are predominately strongly 

saline-alkali Willows clay, Willows silty clay, and Riz silty clay loam 

(Begg 1968). These are wetland soils associated with a high watertable, and subjected to occasional to frequent flooding. A variety of 

salt-tolerant wetland plants naturally occur in this arid, alkali 

landscape. These soils are of limited agricultural productivity, 

supporting rice through the constant application of summer water, 

which translocates salts deep into the soil profile. Sutter Refuge soils 

mostly consist of basin floor deposits (i.e., marsh deposits) 

represented by Oswald clay, frequently flooded in the Bypass, and 

Oswald clay located outside the Bypass (Begg 1968; Lytle 1988; Reed 

2006). 

Several natural creeks and sloughs bisect the Colusa Basin refuges 

including Logan Creek and Hunter Creek on Sacramento Refuge; 

Stone Corral Creek and the Colusa Basin Drain at Delevan Refuge; 

and the Colusa Basin Drain and Powell Slough through Colusa 

Refuge. Numerous drains also bisect these Refuges, such as the 

Northeast Slough and East Slough (Delevan Refuge). 

Sutter Refuge is located at the upper end of the Sutter Basin and lies 

mostly within the Sutter Bypass. This area of the Refuge was 

characterized as a large freshwater sink with a network of sloughs 

associated with the Sacramento River floodplain. 

Prior to land reclamation and flood control, Colusa Basin refuges 

flooded at occasional to frequent intervals. Because of the refuges’ 

Basin Rim location, flood waters quickly receded into the natural 

troughs and sloughs, these eventually drained into the Sacramento 

River or large freshwater sinks, such as in the Sutter Basin, where 

bulrushes (tules) and cattails formed massive impenetrable thickets 

of vegetation (Holmes et al. 1915). This once extensive marshland 

habitat supported abundant and diverse native fish and wildlife. 

Most floodwater was off the Basin Rim during the growing season, 

resulting in a barren, alkali, and windswept plain (Silveira 2000, 

2001). A relatively dense aggregation of large intermittent lakes, 

vernal pools, mima mounds, and alkali sinks and flats characterized 

the Colusa Basin (Holmes et al. 1915), and were historically known as 

the “Colusa Plains.” These natural wetlands filled with winter rains, 

providing abundant waterfowl and shorebird habitat. In the 

springtime a vast parade of wildflowers of every color of the rainbow 

carpeted the Colusa Plains (Hanson 1944; Silveira 2000, 2001). 

50 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

4. Habitat 

4.1. Vegetation 

The Refuges consist mostly of managed wetlands with much smaller 

amounts of unmanaged wetlands, vernal pools, alkali meadows, 

grasslands, riparian forest, and other habitats (Table 4). 

The majority of wetlands are seasonally flooded with 10 to 15 percent 

managed as summer wetlands (Figures 6-9). A comprehensive list of 

plant species can be found in Appendix K. Descriptions of the 

habitats and their associated plant/wildlife species follows. 

Table 4. Acreage and habitats of Sacramento National 

Refuge Complex. 

Acreage 

Refuge Total1 

Managed Wetlands2 

Unmanaged 

Wetlands2 

Vernal 

Pool/Alkali 

Meadow2 Grasslands2, 5 

Riparian 

Forest2,6 Other2,7 

Seasonally 

Flooded 

Wetlands3 

Summer 

Wetlands4 

Sacramento 10,819 6,305 781 163 2,941 139 117 373 

Delevan 5,8778 3,939 661 13 461 464 46 290 

Colusa 4,6869 2,957 390 119 619 438 15 148 

Sutter 2,591 1,708 173 45 0 226 403 36 

TOTAL 23,973 14,909 2,005 340 4,021 1,267 581 847 1

 Official refuge acres. 

2

 Acres calculated with GIS from 2006-07 annual habitat management plans. 

3

 Includes irrigated and non-irrigated seasonally-flooded wetlands. 4 Includes semi-permanent and permanent wetlands. 

5 Includes annual and perennial grasslands 6

 Includes mixed riparian forest, cottonwood willow, willow scrub, and valley oak riparian forest. 7

 Includes roads, facilities, and other miscellaneous areas. 

8 Includes the 80-acre Rennick property. 

9 Includes 646 acres acquired under North Central Valley Wildlife Management Area. 

Sacramento Refuge at sunrise 

Photo by Steve Emmons 

Comprehensive Conservation Plan 51 
Figure 6. Sacramento Refuge Habitat Management Map. 

Chapter 3 

52 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Figure 7. Delevan Refuge Habitat Management Map. 

The Refuge Environment 

Comprehensive Conservation Plan 53 
Figure 8. Colusa Refuge Habitat Management Map. 

Chapter 3 

54 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Figure 9. Sutter Refuge Habitat Management Map. 

The Refuge Environment 

Comprehensive Conservation Plan 55 
Chapter 3 

4.2. Wetlands 

The Central Valley has lost 90 to 95 percent of its original wetlands 

that existed in the late 1800s (Holland 1978; Gilmer et al. 1982; 

Frayer et al. 1989; Kempka and Kollasch 1990). Many of the original 

wetlands in the Sacramento Valley occurred along rivers and creeks, 

where over bank flooding seasonally inundated large expanses of 

wetlands during major rain events and runoff during the spring. In 

areas farther away, isolated vernal pools were also filled directly from 

precipitation, creating significant wetland landscapes. 

Because of historic losses of wetlands, most of the remaining 

wetlands in the Sacramento Valley are intensively managed, 

including those on the Complex. They are managed to maximize 

resources to support the annual abundance of migratory birds, 

endangered and threatened species, and other wetland-dependent 

wildlife. This has been accomplished through creation and 

enhancement of “managed wetlands,” while maintaining and 

restoring natural wetland habitats (vernal pools, vernal pool/alkali 

meadow complex, riparian scrub and forests), when appropriate 

(Mensik and Paveglio 2004). For the most part, managed wetlands 

are artificially created and maintained, with the majority having at 

least some perimeter and interior levees, water control structures, 

and water delivery and drainage canals. Most of the water used to 

flood these wetlands is delivered to Refuge boundaries via local 

irrigation districts. Much of the original infrastructure (water 

conveyance, levees, etc.) was constructed shortly after the Refuges 

were established. In other cases, agricultural fields (see section 4.5 

Agricultural Croplands) provided some levees and water control 

structures that would eventually be modified to facilitate managing 

wetlands. Many of these fields were leveled over the years, with 

equipment of the era, to promote higher yields of crops and millet or 

watergrass. The last major field leveling occurred in the late 1970s, 

associated with the Bicentennial Land Heritage Program (BLHP) 

funding. 

Ironically, in the 1980s, the trend was reversed and an era of 

deleveling was initiated to undo some of the leveling work that had 

been previously completed. Although leveled fields may have 

increased crop or millet yields, the resulting habitat was homogenous, 

lacking diversity in plant species, water depths, and ultimately 

wildlife. During the same period, cooperatively farmed rice 

agriculture on the Refuges was being phased out and wetland 

restoration on private lands was beginning largely on previously 

leveled rice fields. Techniques for deleveling rice fields to convert 

them to managed wetlands were developed (Strong et al. 1990) and 

have been modified for enhancing existing managed wetlands as well. 

This involves the creation of swales and potholes throughout the pond 

bottoms in order to establish a variety of water depths, vegetation 

types, and open water areas. 

56 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Marsh wren 

Photo by Steve Emmons 

The Refuge Environment 

Although agriculture and managed wetlands have replaced much of 

the “plains” landscape in the Sacramento Valley, significant areas of 

vernal pool and alkali meadow habitat complexes and some remnant 

sloughs and ponds still occur on the Refuges. These areas exist as 

“natural” (or unmanaged) wetlands, meaning they are not 

intentionally flooded, drained, or irrigated. Early attempts were 

made to farm or flood some of these areas, but most failed due to the 

alkalinity. 

4.2.1. Seasonally Flooded Wetlands 

Seasonally flooded wetland (SFW) is the most common habitat type 

on the Complex, and comprises 85-90 percent of the total managed 

wetlands on the four Refuges (Table 4). SFW provide the greatest 

density and diversity of food and cover for waterfowl and other 

migratory birds. Consequently, it supports the greatest abundance 

and diversity of wildlife species over the course of a year. During the 

non-breeding season (September-April), SFW can support up to 

three times the average waterfowl densities of semi-permanent 

wetlands and 10 times that of permanent wetlands (M. Wolder, 

unpublished data). These wetlands are intensively managed, with the 

timing and depths of water and vegetation manipulated to meet 

resource management objectives. In general, they are wet from fall 

through spring and dry during the summer. 

Characteristic plants include 

emergent species, such as 

hardstem bulrush, cattail, and both 

alkali and tuberous bulrush. 

Wildlife forage species include 

swamp timothy, smartweeds, and 

watergrass. The ratio of open 

water to emergent plants often 

determines the species that will 

use a particular area. For example, 

pintail, shoveler, wigeon, most 

geese, and shorebirds are species 

attracted to marshes which have 

more open water and less 

emergent cover. When SFW is dry 

during the summer, bulrushes and 

other vegetation function as 

habitat for ground-nesting birds. 

A percentage of SFWs receives a single irrigation during the spring 

or early summer, and are referred to as watergrass (WG) units. 

Watergrass habitat comprises about 10 to 15 percent of the total 

managed wetland acres. It typically contains a large volume of seeds, 

including watergrass, smartweed, and other moist-soil species that 

Comprehensive Conservation Plan 57 
Chapter 3 

are especially sought-after by waterfowl early and late in the season. 

Along with other seasonal wetlands, WG units play a role in providing 

alternate food resources in the early fall to help prevent crop 

depredation on private agricultural lands. 

4.2.2. Summer Wetlands 

Summer wetlands (SW) include permanent and semi-permanent 

wetlands. They provide wetland habitat during all or part of the 

summer, as well as most of the rest of the year. Summer wetlands 

comprise approximately 10 to 15 percent of the total managed 

wetlands (Table 4). Vegetation includes an abundance of perennial 

emergents (cattails and bulrushes), floating-leaved submergents 

(bur-head, arrowheads, etc.), and pondweeds (sago, horned, etc.). SW 

provide important breeding habitat for waterfowl and many other 

wetland-dependent species including egrets, bitterns, ibis, grebes, 

rails, tricolored blackbirds, giant garter snakes, and northwestern 

pond turtles. They are also important water sources for all wildlife 

during the summer, when most seasonal marshes are dry. 

Historically, permanent and semi-permanent wetlands have been 

referred to as “permanent ponds” and “summer water,” respectively 

in Complex habitat management plans and other documents. 

Mallard with ducklings 

Photo by Steven Emmons 

4.2.3. Unmanaged Wetlands 

Wetlands, other than vernal pools, that are largely natural and have 

little or no artificial water management capabilities are referred to as 

“unmanaged wetlands.” They include oxbow lakes, sloughs, and other 

watercourses. They are typically more permanent or semi-permanent 

wetlands that are heavily vegetated. The limited acres of unmanaged 

wetlands provide habitat for giant garter snakes, western pond 

turtles, wood ducks, and other species. 

4.2.4. Vernal Pools/Alkali Meadows 

Natural vegetation at Colusa Basin refuges is best characterized as 

saline vernal pools of the Colusa–Solano Region (Barbour et al. 2003; 

58 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Holland 1978) and alkali meadow plant communities (Griggs et al. 

1992; Holland 1986; Silveira 2000). These Refuges also share a similar 

flora with native salt-tolerant plants, managed freshwater emergent 

plants, and weedy annual grasses (Oswald and Silveira 1995, 2003 

Supplement). A majority of the alkali meadow forbs are natives, while 

most of the grasses are non-natives (Wight 2000). 

Vernal pools are seasonally flooded depressions found on ancient soils 

with an impermeable layer (duripan) such as a hardpan or claypan 

that perches rainwater above the water table. The Riz soil series, 

which has developed on the Modesto Formation, is associated with a 

claypan. The Willows soil series is not associated with a duripan, but 

the high clay content associated with high concentrations of alkali 

impedes percolation of water and causes rainwater to perch above the 

water table in depressions forming vernal pools. They are generally 

filled and maintained with rainwater in the winter and early spring, 

then evaporate as temperatures warm and north winds blow in late 

spring. While temporary wetlands such as vernal (spring) pools occur 

throughout the earth, those of California are unique due to a 

Mediterranean (winter wet–summer dry) climate; thus the flora and 

some of the fauna of vernal pools are unique to California (Holland 

and Jain 1988). Since vernal pools support a significant amount of 

endemic and rare flora and fauna, they add significantly to the biotic 

diversity of the Refuges (Silveira 2000; Eriksen and Belk 1999; Thorp 

and Leong 1995); as a result, they are a high conservation priority. A 

sample of California vernal pool endemics include: Fremont’s 

goldfields; alkali goldfields; Scribe’s popcornflower; Hoover’s 

downingia; folded downingia; vernal pool saltbush; Hoover’s spurge; 

cleistogamous spike primrose; tiny mouse-tail; Colusa grass; hairy 

Orcutt grass; Solono grass; California clam shrimp; California fairy 

shrimp; Conservancy fairy shrimp; midvalley fairy shrimp; and, 

vernal pool tadpole shrimp. 

As winter rains fill the pools, a variety of crustaceans and other 

invertebrates emerge, develop, and reproduce, completing their 

entire life cycle in a single wet season. Vernal pools provide habitat 

for the greatest diversity of fairy shrimp on earth and most of them 

are endemic to California (Eriksen and Belk 1999). Vernal pool plants 

germinate, some underwater, some using special floating leaves and 

air-filled stems to stay afloat. Vernal pools and their surrounding 

plant communities are important habitats for a variety of migratory 

birds (Silveira 1998; Bogiatto and Karnegis 2006). Some of the most 

intensive shorebird use on the Refuges occurs on vernal pools 

(Wolder et al. 1999). 

As water evaporates in the spring, flowering plants produce the 

brightly colored concentric rings of flowers for which vernal pools are 

famous. Host-specific native bees nest in the plant communities, 

which surround vernal pools and pollinate pool flowers; many of these 

native pollinators are endemic species (Thorpe and Leong 1995). 

Comprehensive Conservation Plan 59 
Chapter 3 

Aquatic insects and crustaceans produce cysts and eggs and plants 

produce seeds that are buried in the muddy pool bottom, all of which 

remain dormant in the dry pools until they are flooded again the 

following winter. In their dry phase, vernal pools are really "banks" 

full of resting seeds, cysts, and eggs that are adapted to survive 

through summer, and even extended droughts. 

Vernal pool at Sacramento Refuge 

Photo by Joe Silveira 

Alkali and salt tolerant vegetation grows on Basin Rim landforms, 

which are elevated slightly above the valley or basin floor. Here, the 

plant rooting zone and soil surface is near the water table, so salts (at 

the Refuge, sodium) which increase alkalinity are carried to the 

rooting zone or to the surface forming white-crusted alkali scalds and 

“fluffs.” Alkali meadows are characterized by halophytes (salttolerant plants) and form a unique vegetation, which is sparsely 

vegetated and relatively short. Alkali meadows are often found in 

association with vernal pools at the Complex. While they do not pond 

water like vernal pools, the soil becomes completely saturated with 

winter and spring rainfall. Similar to vernal pools, they support a 

variety of native endemic plant and animal species that are uniquely 

adapted to their environment. Examples of California alkali 

meadow/vernal pool endemics include: pappose spikeweed; Heckard’s 

pepper-grass; heart-scale; brittlescale; Ferris’s milk-vetch; palmatebracted bird’s-beak; and, the Delta green ground beetle. 

Vernal pools and alkali meadows occur most commonly at 

Sacramento, Delevan, and Colusa Refuges (Table 4). They are a 

remnant of the original “Colusa Plains” identified by early settlers as 

the area west of the Sacramento River in the Colusa Basin. The 

habitat was also historically known as “alkali gooseland,” as 

thousands of geese used and continues to seek out these areas for 

grazing. Vernal pools and alkali meadows are technically wetlands, 

but have been historically considered part of the overall “uplands” 

habitat group. 

60 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

4.3. Grasslands 

True upland habitats are relatively uncommon on the Refuges, and 

include annual and perennial grasslands (Table 4). Perennial 

grasslands include some recently restored natives adapted to the less 

alkali soils, and introduced non-native species of tall wheatgrass and 

Harding or perla-grass. Grassland cover provides nesting habitat for 

ducks, pheasants, meadowlarks, burrowing owls, and other grassland 

species. Preliminary monitoring of native grass restoration work at 

Colusa Refuge indicated comparable duck nest densities with other 

off-refuge areas, but with overall higher nest success (Loughman et 

al. 2004). American bitterns and northern harriers also nest in these 

areas. During the winter and spring, short grass uplands provide 

green browse for geese, wigeon, and coots. Uplands also support 

significant numbers of insects, rodents, and reptiles, which, in turn, 

are important forage items for raptors and other birds. Many of the 

non-native grass species are invasive and pose a threat to alkali 

meadow vegetation and the rare, endemic, and native species that 

grow there. As a result, they are controlled in some areas. 

4.4. Riparian Habitats 

Riparian habitats comprise a relatively small proportion of these four 

Refuges (Table 4). Narrow bands of Goodding’s black willow, and 

sometimes, narrow-leaved willow, form willow scrub stands along 

Logan and Stone Corral Creeks, the Colusa Basin Drain, and several 

other water delivery and drainage canals of the Refuges. At 

Sacramento Refuge, a cottonwood willow stand, known locally as 

“Sherwood Forest,” occurs on a small portion of the south half of the 

Refuge. At Colusa Refuge valley oak riparian forest occurs along 

Powell Slough, a small area along the Colusa Basin Drain. Mixed 

riparian forest occurs along the Sutter Bypass canals at Sutter 

Refuge and comprises the largest patches of forested habitat of the 

four Refuges. 

Willow scrub forms open-to-dense shrubby willow-dominated thickets 

with little to no understory vegetation (Holland 1986). It occurs along 

the creeks, sloughs, canals, and drains of the Refuges. Cottonwood 

willow is forested habitat containing open–to-dense stands codominated by willows and Fremont’s cottonwood. Valley oak riparian 

forest is dominated by valley oak and includes an understory of box 

elder, wild rose, poison oak, and alkali (creeping) ryegrass (Holland 

1986; Holland and Roye 1989). Mixed riparian forest is a forest 

vegetation type consisting of later successional species, such as valley 

oak (Holland 1986; Holland and Roye 1989). Valley oak accounts for 

less than 60 percent of the canopy coverage with black walnut and 

Oregon ash also present. Willows and cottonwood may also be 

present in relatively low abundance. The dense understory often 

consists of Oregon ash, box elder, poison oak, and wild grape. Wild 

rose is also a common understory plant. 

Comprehensive Conservation Plan 61 
Chapter 3 

Riparian habitats are used by a great variety of Neotropical migrant 

bird species, including the yellow-billed cuckoo, yellow-rumped 

warbler, black-headed grosbeak, and spotted towhee. Because of 

their close proximity to water, riparian scrub and forest habitats 

attract a large array of “wetland-dependant” species, such as the 

northwestern pond turtle, great blue heron, great egret, wood duck, 

common yellowthroat, song sparrow, beaver, and river otter. 

River otters 

Photo by Mike Carpenter 

4.5. Agricultural Croplands 

Grain crops were annually grown on a number of the Refuge units in 

the 1940s through the mid-1980s, primarily to provide food for 

waterfowl and lure them away from crops on nearby private lands 

(USFWS 1937-1995). Rice and barley were the most common initially, 

but by the 1970s, rice was grown almost exclusively, totaling about 

2,600 acres on the four Refuges. A rice-millet (watergrass) fallow 

rotation was commonly used on certain units to maintain productivity 

and help control weeds. 

By the 1980s, it was apparent that harvested rice fields had become 

an abundant habitat type throughout the Sacramento Valley, while 

freshwater marsh and other natural wetlands had a declining trend 

and were becoming relatively scarce. The Sacramento Valley 

Waterfowl Habitat Management Committee (1983) recommended 

termination of rice farming programs on the Complex. Reduced 

water availability and budget constraints had also made rice 

agriculture difficult. In addition, wetland management techniques 

were producing significant quantities of watergrass and other moistsoil food plants. As a result, rice farming on the Refuges began to be 

phased out in 1984, with no significant increases in depredation 

complaints. The last crop of rice grown on the Complex was in 1988 

(USFWS 1937-95, vol. 1990), and all previous rice fields were 

eventually converted to managed wetlands (Strong et al. 1990; 

Mensik 1993a). 

62 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

5. Habitat Management 

Habitat management strategies are considered at the Complex, 

Refuge, and individual unit level. This management philosophy 

acknowledges conservation needs of both spatial and seasonal 

distributions of different wildlife and plant species. Because of the 

highly mobile nature of migratory birds, their populations readily 

shift among the various basins in the Central Valley (CVJV 2006) and 

individual Refuges within the Complex. For example, wintering 

waterfowl typically shift from northern and western areas of the 

Sacramento Valley (including Sacramento and Delevan Refuges) in 

the early fall to more eastern and southern areas in winter and spring 

(including Sutter and Colusa Refuges, USFWS 1989-2007). In this 

case, food and other habitat resources are provided through strategic 

flood-up scheduling among the Refuges over the course of the year to 

accommodate these seasonal and geographic needs. 

At the refuge level, habitat is manipulated through a variety of 

methods (mostly water and vegetation management) to achieve 

functional percentages of different habitat types. This would include 

meeting objectives for the ratio and spatial distribution of breeding to 

non-breeding habitat types (i.e. summer versus seasonal wetlands). 

Conversely, extremely rare species with limited distributions may 

require intensive management at the unit level to conserve or 

enhance them (i.e. endangered plants, colonial nesting bird rookeries 

or other localized nesting sites). 

There are approximately 270 separate management units on the 

Sacramento, Delevan, Colusa, and Sutter Refuges (USFWS 1989­

2007). Intensively managed wetlands comprise the majority of those 

units. In order to more effectively maintain, manage, and monitor 

these Refuges, a habitat management system was implemented in the 

early 1980s (Mensik and O’Halloran 1990). The system has evolved 

with several modifications and additions, along with some upgraded 

technology, and has been successfully used at the Complex for over 

20 years. 

Refuge management is determined, guided, and tracked by an annual 

habitat management planning process (USFWS 2002a; USFWS 

1988-2007). The annual cycle of this process starts in the spring with 

the generation of an annual habitat management plan (Appendix E) 

for each Refuge. Refuges are toured by staff in the late winter, 

during which each management unit is visited and evaluated. Staff on 

these tours includes the refuge manager, biologist, work leader, 

irrigator, outdoor recreation planner, fire management officer, and 

law enforcement officer. Each unit is evaluated based upon what was 

planned the previous year compared to what actually was 

accomplished in terms of management activities (such as water 

regimes, vegetation control, visitor service improvements, etc.), 

repairs (i.e. levees or replacement of water control structures), and 

Comprehensive Conservation Plan 63 
Chapter 3 

the resulting habitat condition, wildlife use, or other resource data. 

Data and observations collected during the year are presented and 

discussed. Nearly all of this data is collected by unit, so it can be 

compared and evaluated. Examples include vegetation species 

composition, wildlife survey data, disease mortality, wetland 

drawdown and flood-up dates, vegetation control measures conducted 

(i.e. prescribed burning, disking, etc.), quality of visitor service 

opportunities (i.e. wildlife observation on tour routes, hunting 

success, etc.), and law enforcement issues. Annual habitat 

management plans (Appendix E) are then generated for each Refuge 

with participation, input, and review from the above staff. This 

process also involves a number of other considerations including, but 

not limited to, refuge purposes, Service management directives (i.e. 

Improvement Act), historic habitat conditions, other regional habitat 

plans (i.e. Central Valley Joint Venture Implementation Plan), 

Flyway management plans, endemic species conservation, 

endangered species recovery plans, and specific resource needs. 

Black-tailed deer in Colusa Refuge 

Photo by Mike Peters 

Data, reports, and documents that are used in the plan are stored and 

generated in a computer database. These plans identify individual 

management units within each Refuge. These units consist of tracts 

of land which have common management constraints, conditions, and 

visitor service activities. The habitat management plan identifies 

physical attributes of the unit, habitat objectives, specifies 

management activities to make any necessary repairs or 

improvements; emphasizes positive results from previous years; and 

notes special management considerations (i.e. presence of special 

status species or other significant wildlife use). It also prioritizes 

management activities and projects based on the overall condition 

and functionality of the unit, water management regimes (i.e. flood-up 

and drawdown schedules), and available resources (i.e. manpower and 

funding). Examples of management activities include facilities 

maintenance (i.e. levees, water control structures, roads, fire breaks, 

fences, gates, boundary signs, etc.), vegetation management (i.e. 

64 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

herbicide application, prescribed fire, grazing, mowing and disking, 

irrigation, etc.), biological surveys, habitat restoration, research, 

visitor service monitoring and facilities maintenance, and law 

enforcement issues. 

The result is a document that is distributed to all staff members for 

reference and to serve as a place to keep notes on their respective 

programs and responsibilities. Their information is then used to help 

generate the following year’s plan. In summary, the habitat 

management plan facilitates the adaptive management process. It 

allows for modification within or between years based on changing 

conditions, serves as a place to input current data from all Refuge 

programs to be considered together, and helps to ensure that 

informed management decisions are made. 

5.1. Water Management 

Proper water management is considered essential to maintaining 

high quality wetlands and meeting the purposes, goals, and objectives 

of the Complex. This includes maximizing benefits for wildlife, 

emphasizing feeding and resting areas for wintering waterfowl and 

other migratory birds. Adequate flows of water through wetland 

units are maintained to promote water quality. At Sutter Refuge, this 

is particularly important to provide passage of migrating juvenile 

salmonids during periods when they may be present. 

Water management is the most important tool for vegetation 

production and control in wetlands. The water management regime, 

specifically the timing, depth, and duration of inundation, is often the 

greatest contributor to the resulting wetland vegetation, whether 

desirable or undesirable (Mensik and Reid 1995). Spring drawdown 

dates largely determine the species that germinate in seasonal 

wetlands (Strong et al. 1990). If drawdowns are conducted too early, 

less desirable cool season emergents and upland grasses will 

dominate. Conversely, if conducted too late, pond bottoms dry too 

quickly and plant germination and survival will be poor overall. 

Water level management is also critical to providing available habitat 

to certain wildlife species at certain times of year (Helmers 1992; 

Isola 1998). For example, providing a variety of shallow water levels 

from 0.3 to 13.4 inches (0.8 to 34 cm) offers attractive foraging habitat 

for most dabbling ducks (Heitmeyer and Raveling 1988) and 

shorebirds (Isola 1998). Conversely, deeper water wetlands are 

needed to support diving birds, such as diving ducks, grebes, 

cormorants, and pelicans. Managed wetlands typically provide a 

range of shallow to deep-water areas, but enhancement techniques 

(Strong et al. 1990) are used to create and maintain this diversity in 

previously farmed or leveled units. 

Most wetlands are created and maintained on man-made 

impoundments, using BOR/CVPIA water that is delivered through 

local irrigation districts. The wetlands are flooded up and drawn 

Comprehensive Conservation Plan 65 
 

 

 

 

 

Chapter 3 

down with near complete control through inlet and outlet 

structures. The number of management units dedicated to 

wetlands ranges from about 25 on Sutter Refuge to 110 on 

Sacramento Refuge. Flooding regimes are designed to mimic 

historic wetland patterns as closely as possible, given water 

availability and wetland losses. Furthermore, the timing of 

drawdowns, irrigations, and floodups largely dictates plant species 

composition (i.e. germination and growth of desirable food and 

cover plants). It also governs habitat availability (i.e. how much 

wetland is flooded at certain times of the year for certain wildlife 

species). 

The amount of water needed each month to manage various 

wetland habitat types is based upon when/how long they are 

flooded/maintained over the course of a year (Table 5). 

Table 5. Approximate number of acre-feet/acre/month 

required for each wetland habitat type on the Complex. 

Currently Available Projected Totals 

(acre-feet/acre) (acre-feet/acre) (acre-feet/acre) 

HABITAT APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR Current Yearly 

Seasonal 0.50 2.00 1.00 0.75 0.25 0.25 0.25 0.50 4.25 5.50 

flooded Floodwetlands up 

Sept 1 – Apr 

1 

Watergrass 

Sept 1 – May 

1 

1.00 1.50 

Irrigation 

2.00 

Floodup 

1.00 0.75 0.25 0.25 0.25 0.50 6.25 7.50 

Summer 1.00 1.00 2.00 1.00 2.00 0.75 0.25 0.25 0.25 0.50 7.75 9.00 

Water FloodOct 1 – July up 

15 

Permanent 1.00 1.50 2.00 2.00 2.00 1.75 1.00 0.75 0.25 0.25 0.25 0.50 12.00 13.25 

Pond 

Jan 1- Dec 

31 

5.1.1. Seasonally flooded wetlands 

During the fall and winter months, water levels in most seasonally 

flooded wetland (SFW) units are kept relatively shallow (<12 

inches), with portions of some units up to 36 inches. In the spring, 

water levels in individual SFW units are slowly drawn down to 

mostly mudflat, typically over a period of 10 to 20 days. These unit 

drawdowns are staggered over the period of March-May, with 

peak drawdown acres occurring in April to coincide with the 

spring shorebird migration. As water is removed, migrating 

shorebirds and other waterbirds utilize the shallow water areas 

and mudflats to feed on invertebrates, fish, and other food items 

that are concentrated in the receding water. Seed-producing 

plants germinate and grow to maturity on the moist pond bottoms 

during the spring and summer. In the fall, individual units are 

66 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
5.1.2. Watergrass 

Watergrass (WG) is simply a seasonal wetland that receives a late 

spring or summer irrigation as part of the management regime. 

WG units are usually drawn down in May, during warmer 

conditions that favor watergrass germination. A single irrigation is 

applied sometime between May and early July, depending on 

weather patterns and phenology of target plant species (Mensik 

1993b) or target pest species (Mensik and Reid 1995). Rapid 

irrigations are desirable, ideally lasting 7-10 days to minimize both 

mosquito production and the growth of undesirable plant species 

such as jointgrass or Bermuda grass (Kwasny et al. 2004). During 

irrigation and drawdown periods, WG units are used by duck 

broods, long-legged waterbirds (e.g. egrets, herons, ibis), and 

giant garter snakes for foraging and cover. After irrigations, WG 

remains dry until flooded up in August or September. During this 

dry period, any prescribed vegetation management such as 

disking or mowing will be conducted. By flooding these habitats in 

late summer or early fall, early migrating waterfowl are provided 

abundant food resources that might otherwise be obtained from 

agricultural crops (primarily rice) on private lands. Colusa and 

Sutter Refuges were authorized, at least partially, by the Lea Act; 

therefore, reducing crop depredation is a major goal of both 

Refuges. 

5.1.3. Summer wetlands 

Consisting of both semi-permanent and permanent wetlands, 

summer wetlands (SW) water depths range from 12 to 48 inches. 

Water levels are maintained at consistent levels, to the extent 

possible, to minimize negative impacts to birds that build their 

nests over the water, growth of undesirable vegetation, and 

The Refuge Environment 

flooded on a staggered schedule (similar to spring drawdowns) 

between late August and November, making appropriate amounts 

of habitat available to fall migrating birds and other wildlife as 

their numbers increase. 

Cinnamon Teal 

Photo by Steve Emmons 

Comprehensive Conservation Plan 67 
Chapter 3 

mosquito production. A flow-though of water is also maintained to 

reduce potential for avian botulism outbreaks. SW is typically 

managed and maintained through one of three (two semipermanent and one permanent) water management regimes. 

The first water management strategy is to keep units flooded into 

the summer and draw them down in July or August, after the 

breeding season. Staggered drawdowns for these units during this 

time attract and support shorebirds during important fall 

migration periods (CVJV 2006). They also provide significant 

foraging sites for a variety of other waterbirds. After drawdowns, 

the units are then reflooded during the fall. During the nongrowing season (i.e. November-April, varies with year), SW units 

are drawn down to even more shallow levels to encourage use by 

wintering waterfowl and other wildlife. 

The second strategy is to flood and maintain throughout the year 

as a permanent wetland. Permanent wetlands may be maintained 

for up to five years or more, but without periodic drawdowns, 

productivity decreases over time. In addition, emergent vegetation 

grows relatively fast and its density can become a problem. As a 

result, these units are typically drawn down every three to five 

years to recycle nutrients, discourage carp populations (which are 

detrimental to desirable submerged aquatic vegetation), and 

conduct any required maintenance or vegetation control. 

Occasionally, a third approach is employed involving a spring 

drawdown to accommodate any maintenance required (i.e. levee 

repair, water control structure replacement, etc.), after which the 

unit is immediately reflooded for the remainder of the season. 

Any of these strategies may be employed in the short-term (i.e. for 

one year out of many) to encourage growth of emergent plants to 

enhance sparsely vegetated units. 

5.1.4. Vernal Pools and Alkali Meadows 

Management of vernal pool and alkali meadows is much less intensive 

than managed wetlands. Water management on vernal pools is not 

artificially manipulated and, in fact, special emphasis is made to 

restore and maintain natural hydrology as much as possible (Silveira 

2007; USFWS 1999b; Ducks Unlimited 2005a, 2005b). They are 

allowed to flood and dry naturally, based on precipitation or natural 

flood events and evaporation. This cycle is what helps maintain the 

abundance and variety of rare and endemic plant and animal species 

that exist on these sites. 

5.2. Vegetation Management 

Vegetation management is relatively common on the Refuges, and is 

generally used to control the abundance of certain plant species or 

their distribution, and to enhance desirable species (Mensik 1990; 

68 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Mensik and Reid 1995). A number of invasive species occur 

throughout the Refuges habitat types and infrastructure (i.e. canals, 

levees, roads, etc.), requiring different levels of control (Table 6). The 

area’s mild climate creates a year-round growing season that results 

in the germination and expansion of at least some undesirable species 

throughout the year. 

Reasons for vegetation management include maintaining 

biodiversity, maintaining desirable proportions of emergent 

vegetation in wetlands, enhancement of desirable species, reduction 

of undesirable species, preparation for habitat restoration projects, 

reducing mosquito breeding habitat, and maintenance and safety 

around facilities including protecting communities and assets at risk 

to wildfire. A variety of vegetation management techniques (mow, 

disk, burn, spray, etc.) are used, depending on the habitat type, plant 

species, and resource objectives. Some are used alone, while others 

may be used in combination with one or more other techniques. In 

general, mechanical methods are preferred over herbicides, but in 

some cases, the opposite is true (i.e. to avoid ground disturbance an 

herbicide may be the most effective method). The need to use any of 

these techniques annually depends on species present, condition of 

the habitat, effects of climate on plant growth, available funding and 

resources, and in some cases, the extent to which legal mandates 

allow the selected technique (i.e. burning restrictions due to local air 

quality legislation). Vegetation management is a primary component 

of the annual habitat management plans, where control and 

enhancement objectives are identified and treatments are prescribed 

to achieve them. 

5.2.1. Prescribed Burning 

Prescribed burning is used in wetland, vernal pool/alkali meadow, and 

grassland habitats to remove hazardous fuel loads, control non-native 

invasive species, as well as to enhance and maintain habitat values. 

Burning in wetland areas is generally used to reduce perennial 

vegetation that has expanded to a point that decreased wildlife use 

and overall productivity has resulted. Examples include wetlands 

where long-term expansion of hard-stemmed bulrush and cattail 

growth have exceeded the optimum range of emergent vegetation 

and open water, or where Bermuda grass or jointgrass has replaced 

the majority of annual moist soil food plants, thus reducing the use by 

many wildlife species (Mensik 1990). These burns also serve to break 

up large stands of continuous fuel beds that can result in larger more 

destructive wildfires. Typically, prescribed burns are applied to 

managed wetlands during spring or summer. Depending on 

conditions and habitat objectives, both dry and overwater burning 

can be successful. Fire lines are disked around the burn area and 

buffers are disked around any trees to be saved. The firing pattern 

allows for an avenue or direction of escape for wildlife. In some cases, 

burning is conducted over water to increase controllability. Follow-up 

disking is often used to ensure that roots of target species (i.e. hardComprehensive Conservation Plan 69 
 

Chapter 3 

stemmed bulrush, cattail, jointgrass, etc.) are killed and enhance 

germination of desirable species (Mensik 1990; Mensik and Reid 

1995). The result is a desirable mix of vegetation species, stature, and 

distribution; a recycling of nutrients; and a successional stage that is 

more productive and reduces the risk to life and property from larger 

more destructive wildfires. The frequency of burning wetland units 

depends on habitat type, vegetation species composition, soil type, 

and tendency for growth. In some cases, this may be as often as once 

every five years and in others, it may be one in 20 to 30 years. 

Prescribed burns in grasslands, alkali meadows, and vernal pools are 

used to reduce invasive species and stimulate native plant species 

(Pollak and Kan 1998; Wight 2000). Resource benefits include 

maintaining biodiversity (especially native plant communities and the 

wildlife they support), providing browse for waterfowl, and general 

maintenance of habitat for short grass wildlife species. These burns 

also reduce the risk of large unwanted wildfires by reducing the 

accumulation of hazardous fuels and establishing a mosaic of fuel 

loads. Burns may occur at any time of year, depending on specific 

objectives and condition of the habitat. Fall or winter burns are 

usually used when sensitive plants are present because they are 

dormant at that time. For optimal control of annual grasses, it is most 

effective to burn in the late spring/early summer, when seeds remain 

on the plants and can be easily consumed by the fire. 

Prescribed burning 

Photo by Kipp Morrill 

Annually, 500 to 2,000 acres of wetland, vernal pool/alkali meadow, 

and grassland habitats are burned on the four Refuges. Prescribed 

burns are conducted in accordance with both Department of the 

Interior and Service Fire Management Policy (621 FW 1-3 of the 

Service Manual). Use of prescribed burns for habitat management 

and hazardous fuel reduction is consistent with both the approved 

habitat and Fire Management Plans for the Complex (Appendix J). 

Individual prescribed burn plans are written, reviewed, and approved 

70 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

for each unit as outlined in the Interagency Prescribed Fire Guide. 

They include a variety of information detailing how the burn will be 

conducted, considerations for safety, and measures to minimize 

impacts to sensitive species and air quality. All prescribed burns are 

conducted in compliance with the Clean Air Act and associated 

permitting requirements. 

5.2.2. Disking 

Disking is an important management tool that has a variety of uses. 

It is commonly used in managed wetlands to reduce vegetation that 

has exceeded beneficial quantities or distributions required for 

wildlife use objectives. By itself, or in combination with burning or 

spraying, disking helps control bulrushes, cattails, Bermuda grass, 

jointgrass, primrose, and other perennial plant species (Mensik 1990; 

Mensik and Reid 1995). In addition to controlling undesirable plants, 

disking also creates a seedbed conducive to both increased 

germination and seed production of desirable moist soil plants in 

seasonal wetlands (Naylor 2002). Caution must be exercised in some 

wetlands, where disking can enhance or spread invasive species, such 

as cocklebur and pepperweed. Disking is often used in thick 

vegetation to create openings that facilitate bird disease monitoring 

and carcass removal, as well as to increase wildlife viewing 

opportunities. Waterbird loafing areas can be greatly enhanced by 

reducing vegetation on islands and interior levees. As the use of 

prescribed burning has declined due to local air quality restrictions, 

disking has become a more frequent vegetation control option. 

Disked fuel breaks are particularly effective in the Wildland Urban 

Interface (WUI) where prescribed burns are more difficult. Disked 

fuel breaks are used to protect life and property from the spread of 

wildfire off of and onto the Refuges. 

Disking jointgrass 

Photo by Mike Carpenter 

Disking is typically conducted during late spring, summer or early 

fall months when wetlands are dry. Target species/areas may be 

Comprehensive Conservation Plan 71 
disked one or more times to ensure that roots are dead, reducing the 

need for more frequent treatments. Vegetation succession is set back 

in disked areas, and typically desirable moist soil plants and open 

water areas replace the species that are removed. Multiple disk 

passes are sometimes necessary to break up large clods for optimal 

germination. 

Circumstances dictate how much of an area will be disked. In most 

cases, a mosaic pattern is created, leaving equal proportions of 

emergent cover plants and open areas with annual moist soil plants. 

The amount left undisked may be altered if special needs for certain 

species are identified (Mensik and Reid 1995). Examples include 

leaving more emergent vegetation in units that have historical use by 

colonial nesting birds, such as tricolored blackbirds or white-faced 

ibis, or leaving less vegetation in units that support large numbers of 

open water species, such as pintails or shorebirds. In cases of 

widespread problem vegetation, sometimes the most cost-effective 

treatment is for the majority of a unit to be disked, realizing that the 

benefits will last a minimum of 3 to 5 years (Mensik and Reid 1995). 

5.2.3. Mowing 

Mowing is used to control a variety of invasive species, enhance 

wetlands, reduce fire risk, and accomplish general weed maintenance 

around facilities. It is usually conducted with a tractor pulling a large 

mowing implement, but may also be accomplished with smaller 

equipment, such as push mowers or weed eaters. 

Chapter 3 

Mowing cocklebur 

Photo by Mike Carpenter 

In wetlands, mowing is a primary tool for controlling cocklebur, an 

invasive species that can overtake seasonal wetlands and crowd out 

more desirable species (Mensik and Reid 1995). By mowing prior to 

plants setting seed, cocklebur can be kept under control, resulting in 

a greater diversity of desirable species, while reducing the need to 

72 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

use herbicides. Mowing is also used for keeping islands and selected 

sections of levees clear of vegetation. This greatly enhances wetlands 

by creating optimal loafing and resting sites for waterfowl, 

shorebirds, and other wildlife. Whenever possible, mowing is used 

instead of disking in order to minimize erosion and invasive species 

expansion. 

Invasive vegetation in upland habitats is also managed with mowing, 

although burning or grazing are preferred in most cases. Yellow 

starthistle and non-native grasses such as annual ryegrass can be 

significantly reduced by mowing, but timing is critical (Thomsen et al. 

1997). 

A number of roads, levees, and areas around buildings and other 

facilities are mowed during the spring and summer to minimize risk 

of wildfires by allowing safer access to complete habitat management 

tasks (i.e. checking water control structures), conduct biological 

surveys, and perform general maintenance. 

5.2.4. Spraying 

When mechanical or biological methods are ineffective or impractical, 

herbicides are used on the Refuges for invasive species control. All 

herbicide use is reviewed and approved through the same Pesticide 

Use Proposal (PUP) process (7 RM 14 of the Refuge Manual). A PUP 

is prepared for each material used. It identifies target species; reason 

for application; application rate, timing, and method; sensitive areas 

and species that may be affected and measures to avoid impacts to 

them. PUPs are 

reviewed and can be 

approved by the 

refuge manager, 

regional office, or 

Washington office, 

depending on the 

type of material used. 

For more 

information, see the 

Integrated Pest 

Management Plan in 

Appendix F. 

Herbicide spraying 

Photo by Mike Carpenter 

5.2.5. Water Management (for vegetation control) 

Water management is the most important tool for vegetation 

enhancement and control in wetlands. The timing, depth, and 

duration of flooding can be manipulated to enhance desirable moist 

soil plants and reduce certain undesirable species. Short-term 

irrigations (7-10 days) conducted in the spring and summer can 

Comprehensive Conservation Plan 73 
greatly increase the amount of moist soil plant seed production 

(Naylor 2002) and vegetative stature in seasonal wetlands. One 

irrigation is typically all that is necessary to bring seedling plants to 

maturity. 

Cocklebur, a common invasive species in seasonal wetlands, is 

particularly susceptible to control by flooding at a critical point in its 

life cycle. As with many desirable species, such as watergrass or 

smartweeds, cocklebur seedlings germinate on seasonal wetland pond 

bottoms as they dry in spring. To control cocklebur, reflooding the 

wetlands for one to two weeks at the right time can kill cocklebur 

seedlings, while at the same time encouraging the growth of desirable 

species. 

However, if irrigated for a prolonged period, problem species such as 

Bermuda grass or jointgrass, can rapidly encroach, resulting in 

decreased overall productivity for wildlife and potentially 

unacceptable levels of mosquito production (a human health issue in 

some areas). 

5.2.6. Restoration of native species 

Where appropriate, native vegetation is restored on the Refuge using 

a variety of grasses, forbs, shrubs, or tree species depending on 

habitat and wildlife objectives. Planting seeds, plugs, and cuttings are 

the most common methods for establishing native vegetation. The use 

of the most local genetic stocks for any plantings helps to increase the 

chance of success. 

5.2.7. Prescribed livestock grazing 

Historically, grazing by native wildlife species has shaped the 

botanical and zoological resources of the California landscape 

(Edwards 1992, 1996). Currently, well managed livestock grazing is 

an important method of vegetation management (Barry 2003; Griggs 

2000) on the Refuges. Benefits associated with the grazing program 

include: the reduction of plant material; reduction in non-native 

invasive weeds (Thomsen et al. 1993); increases in native plants, 

including special status plant species due to reduced competition for 

sunlight, reduced competition with non-native annual grasses for 

water and nutrients (Coppoletta and Moritsch 2001; Davis and 

Sherman 1992; Menke 1992; Muir and Moseley 1994); increased 

primary production and resultant increases in plant biomass 

(McNaughton 1985); increases in native vernal pool and grassland 

wildflowers (Marty 2004, 2005), with consequent increases in macroinvertebrate populations, including native pollinators of native plants, 

and prey items for Refuge wildlife such as migratory land birds like 

the horned lark and savanna sparrow; and increases in the inundation 

period with habitat benefits to vernal pool crustaceans (Pyke and 

Marty 2005). Grazing provides optimal shorebird and sandhill crane 

foraging habitat by reducing grass height and contributing organic 

matter for the prey base (Colwell and Dodd 1995; Knopf and Rupert 

Chapter 3 

74 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

1995) and also provides short, nutritious grasses for grazing 

migratory waterfowl (Buchsbaum et al. 1986) and local deer. Aquatic 

invertebrates, insects, and special status species associated with 

vernal pool and vernal pool/alkali meadow complexes benefit from 

grazed herbaceous habitats (Bratton 1990; Bratton and Fryer 1990; 

Panzer 1988; Germano et al. 2001), especially cattle grazing (Marty 

2004, 2005). Grazed areas support increased numbers of primary 

burrowing mammals such as the California ground squirrel and 

secondary burrowing animals, such as burrowing owls and various 

snakes. 

Grazing can also impact some Refuge wildlife and 

habitat, including reducing nesting cover for some 

nesting waterfowl and songbirds, (Kirsch 1969; 

Krueper 1993), as well as for the northern harrier 

and American bittern. Mammals which burrow 

through thatch, such as California meadow vole, 

would likely decrease with grazing. However, these 

impacts would be short-term because the program 

would stipulate seasonal grazing (Appendix B, 

Grazing Compatibility Determination). 

Primary, long-term benefits from the grazing 

program include continued annual native plant 

production, non-native invasive plant species control, 

and maintenance of annual or seasonal use of Refuge 

habitat by migratory birds and resident deer herds. 

Periodic grazing can also lessen the threat of wildfire 

near rural structures and agricultural industrial 

facilities. 

Overall, the short-term impacts of seasonal grazing on local groundnesting birds and some small mammals would be mitigated by the 

long-term improvements to Refuge plant species composition and 

structure, native plants, and overall wildlife habitat quality that 

would benefit migratory birds, resident deer herds and nesting 

habitat condition. 

Grazing is facilitated through the Cooperative Land Management 

Agreement (CLMA) or Refuge Special Use Permit (SUP) with a local 

cooperator. Benefits of the CLMA program are the cooperator’s 

shared responsibilities in maintaining corals, fences, gates, cattle 

water systems, and vegetation management/invasive weed control. 

Burrowing owl 

Photo by Mike Peters 

Comprehensive Conservation Plan 75 
Chapter 3 

5.3. Control of Invasive, Exotic, or Pest Species 

It is necessary to control certain plant and animal species that have 

undesirable effects on Refuge animals, plants, and their habitats or 

pose a health risk. The Refuges actively control or permit the control 

of a number of invasive and/or exotic plants (Table 6), problematic 

animals, and disease vectors. Invasive plant species compete with 

desirable plants for space, sunlight, nutrients, and water. They have 

detrimental effects on the distribution and abundance of plants that 

are important to wildlife as food, shelter, and nesting areas. In some 

cases, certain plants may be desirable in modest proportions, but can 

be detrimental to diversity and productivity if they become dominant. 

The Service Pest Management Policy goal (30 AM 12.1 of the 

Administrative Manual) is to eliminate the unnecessary use of 

pesticides through the use of Integrated Pest Management (IPM). 

IPM uses a combination of biological, physical, cultural, and chemical 

control methods (30 AM 12.5 of the Administrative Manual). This 

approach notes environmental hazards, efficacy, costs, and 

vulnerability of the pest. 

When plants or animals are considered a pest, they are subject to 

control on national wildlife refuges if the pest organism represents a 

threat to human health, well-being, or private property; the 

acceptable level of damage by the pest has been exceeded; State or 

local governments have designated the pest as noxious; the pest 

organism is detrimental to primary Refuge objectives; and the 

planned control program will not conflict with the attainment of 

Refuge objectives or the purposes for which the Refuge is managed 

(7 RM 14.2 of the Refuge Manual). 

The Refuges have developed a draft Integrated Pest Management 

Plan for the Complex (Appendix F) to control invasive, exotic, or pest 

plant species. 

76 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

 

The Refuge Environment 

Table 6. Invasive Plant Species at Sacramento Refuge Complex. 

Species 1 Common Name Habitat 2 

ASTERACEAE 

[Compositae] 

SUNFLOWER FAMILY

 Centaurea solstitialis YELLOW STAR-THISTLE Grassland, fields, levees, 

roadsides, ditch banks 

Lactuca serriola PRICKLY LETTUCE Grassland, fields, levees, 

roadsides, ditch banks 

 Xanthium strumarium ROUGH COCKLEBUR SFW, riparian habitats, vernal 

pools 

BRASSICACEAE 

[Cruciferae] 

MUSTARD FAMILY

 Lepidium latifolium BROAD-LEAVED 

PEPPERWEED 

SFW, riparian habitats, fields, 

levees, ditch banks 

CHENOPODIACEAE GOOSEFOOT FAMILY

 Salsola soda FLESHY-LEAVED 

RUSSIAN-THISTLE 

Alkali meadows, non-native 

alkali grassland 

CONVOLVULACEAE MORNING-GLORY 

FAMILY

 Convolvulus arvensis BINDWEED Vernal pools 

FABACEAE LEGUME FAMILY

 Robinia pseudoacacia BLACK LOCUST Riparian Forest 

HALORAGACEAE WATER-MILFOIL 

FAMILY

 Myriophyllum 

aquaticum 

PARROT’S-FEATHER Wetlands, ditches 

JUGLANDACEAE WALNUT FAMILY

 Juglans californica var. 

hindsii 3 

NORTHERN 

CALIFORNIA BLACK 

WALNUT 

Riparian Forest 

MORACEAE MULBERRY FAMILY

 Ficus carica FIG Riparian Forest 

MYRTACEAE MYRTLE FAMILY

 Eucalyptus 

camaldulensis 

RIVER RED GUM Various 

ONAGRACEAE EVENING-PRIMROSE 

FAMILY

 Ludwigia peploides ssp. 

Peploides 

YELLOW WATERWEED Wetlands, ditches 

Ludwigia peploides ssp. 

Montevidensis 

MONTEVIDEO 

WATERWEED 

Wetlands, ditches 

Comprehensive Conservation Plan 77 
 

 

 

 

 

Chapter 3 

Species 1 Common Name Habitat 2 

PHYTOLACCACEAE POKEWEED FAMILY

 Phytolacca Americana AMERICAN POKEWEED Riparian, disturbed 

SCROPHULARIACEAE FIGWORT FAMILY

 Kickxia elatine SHARP-LEAVED 

FLUELLIN 

Various disturbed 

SIMAROUBACEAE QUASSIA FAMILY

 Ailanthus altissima TREE-OF-HEAVEN Riparian Forest 

TAMARICACEAE TAMARISK FAMILY

 Tamarix parviflora SMALL-FLOWERED 

TAMARISK 

Riparian habitats

 Tamarix ramosissima SALT-CEDAR Riparian habitats 

POACEAE [Gramineae] GRASS FAMILY

 Arundo donax GIANT-REED Riparian habitats, ditches 

Crypsis schoenoides SWAMP-TIMOTHY Vernal pools 

Crypsis vaginiflora AFRICAN PRICKLEGRASS Vernal pools 

 Cynodon dactyton BERMUDA-GRASS Various

 Elytrigia pontica ssp. 

Pontica 

TALL WHEATGRASS Alkali meadows 

 Phalaris aquatica HARDING-GRASS, PERLAGRASS 

Alkali meadows 

 Lolium multiflorum ANNUAL RYEGRASS Various

 Sorghum halepense JOHNSONGRASS Upland and wetland 

edges (fields, ditches, 

roadsides) 

Taeniatherum caputmedusae 

MEDUSA-HEAD Uplands 

Paspalum distichum JOINTGRASS/KNOTGRASS Managed wetlands 

 Rubus discolor HIMALAYAN 

BLACKBERRY 

Riparian habitats 

1

 Non-native plants are indicated by an italic font. Severe problem plants indicated 

by underline. 2

 SFW – Seasonal-flooded Wetlands. 

3

 Feral hybrid with commercial English walnut (J. regia). 

78 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

5.4. Mosquito Management 

The Complex is striving to responsibly address risks to public health 

and safety and to protect trust resources from mosquito-borne 

diseases and the impacts of mosquito pesticides on wildlife and the 

ecosystem. Refuge staff works cooperatively with the local Mosquito 

and Vector Control Districts (Districts) in the management of 

mosquitoes on the Refuges. Mosquito species found in the Central 

Valley include important vectors of potentially lethal diseases, 

including encephalitis and West Nile Virus. The Refuge has 

developed a draft Integrated Pest Management Plan for the Complex 

(Appendix F). The plan advocates a process to control mosquitoes, 

when necessary, using the least toxic methods first (i.e. wetland 

management techniques, biological controls) and only using chemical 

pesticides if less aggressive methods are ineffective. A significant 

component of the plan is the implementation of best management 

practices for minimizing mosquito production and mosquito control, 

which includes a variety of techniques for water and vegetation 

management and design features for managed wetlands (Kwasny et 

al. 2004). 

The Service policy (7 RM 14 of the Refuge Manual) dictates that 

Pesticide Use Proposals (PUP) must be developed and reviewed prior 

to the application of any pesticide on a refuge. PUPs are developed 

annually on the Complex with input from the Districts. A PUP is 

prepared for each material used. It identifies target species; reason 

for application; application rate, timing, and method; sensitive areas 

and species that may be affected and measures to avoid impacts to 

them. Depending on the type of material used, PUPs are reviewed 

and can be approved at the refuge manager, regional office, or 

Washington office level. All PUPs are reviewed by the refuge 

manager for consistency with Departmental, Service, regional, and 

State policies. 

Currently, there are varying levels of mosquito control that occur, 

depending on the refuge and annual conditions, such as weather and 

detection of disease. The use of adulticides is the most commonly 

used control method if wetland management techniques are 

unsuccessful. The Refuges continue to work with the local Districts to 

minimize adulticide use and look for additional ways to conduct 

mosquito control that are less toxic, such as some biological 

larvicides. Cost is often the reason larvicides are not more commonly 

used, and continues to be a major factor in trying to further 

implement their use. 

6. Fish and Wildlife 

Given the variety of habitats on the Complex, a great diversity of 

animal and plant species occur here. While many species are common 

year-round, others are here only during migration, for the winter, or 

during the spring and summer months to breed. Appendix K contains 

a complete list of fish and wildlife species that occur or potentially 

Comprehensive Conservation Plan 79 
Chapter 3 

could occur on the Sacramento, Delevan, Colusa, and Sutter Refuges. 

An overview of wildlife use of the Refuges follows. 

6.1. Waterfowl 

The Central Valley of California has always been a major wintering 

area for Pacific Flyway waterfowl. Populations have fluctuated over 

the last century, with some species experiencing significant declines, 

others showing dramatic recoveries, and still others that have shifted 

their distribution away from California. During the 1970s, California 

mid-winter waterfowl surveys, as indexed by the Mid-winter Indices, 

routinely estimated between four and six million ducks and five to six 

hundred thousand geese. Pintails comprised the majority of ducks, 

outnumbering all other species combined. 

Northern Pintail 

Photo by Steve Emmons 

Following the 1970s, extended droughts in the Canadian prairie 

breeding areas caused significant declines in breeding ducks and 

production. These declines were also reflected in wintering numbers 

in California’s Central Valley. Comparatively, in the last 25 years, 

wintering ducks in California (of which most are in the Central 

Valley) have fluctuated between two and four million ducks, including 

only about one to one and a half million pintails (USFWS 1955-2007) 

as shown in the Mid-winter Indices (Figure 10). 

However, when the droughts in the prairies ended in the 1990s, most 

other duck species showed significant increases, but pintails showed 

only modest increases. There is evidence that changes in agricultural 

practices in the Canadian prairies initiated in the 1970s have 

negatively impacted the early nesting habitats of pintails and are 

thought to be the primary reason for the their lagging recovery 

(Miller et al. 2003, Guyn 2004). 

80 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Figure 10. California Mid-winter Indices (USFWS 1965-

2007). 

California Mid-winter Indicies for Pintail vs. 

"All Other Ducks" in California, 1965-2007 

7,000 

(1000's)

6,000 

5,000 

4,000 

3,000 

2,000 

1,000 

0 

Pintails 

All Other Ducks 

65 70 75 80 85 90 95 00 05 

Year 

 

The Refuge Environment 

In general, goose populations have undergone some significant 

changes and shifts in the last thirty years. White-fronted and cackling 

cackling goose (cackler) populations reached their lowest levels in the 

early 1980s, due mainly to over harvest on both wintering and arctic 

breeding areas. Following the implementation of more restrictive 

harvest regulations, both these populations have rebounded 

dramatically. Although cackler populations have increased to a level 

of 150,000-200,000 birds, very few winter in California. Historically, 

about 90 percent wintered in the Central Valley and 10 percent in the 

Willamette Valley, Oregon. Today, this distribution has essentially 

reversed, largely due to turf agriculture in Oregon attracting the 

majority of wintering cacklers. 

Aleutian cackling geese (Aleutian goose) represent another successful 

recovery story. On the brink of extinction with only about 800 birds in 

1975, Aleutian goose populations have rebounded to over 100,000 

today. This has largely been the result of removing non-native 

predators and repopulating geese on their key breeding areas in the 

Aleutian Islands (USFWS 2005a; Pacific Flyway Study Committee 

1999; USFWS 1982). Once on the endangered species list, they were 

delisted in 2001. 

Comprehensive Conservation Plan 81 
Chapter 3 

Aleutian cackling geese 

Photo by Mike Peters 

White goose populations of lesser snow (snow) and Ross’s geese in 

California have remained relatively stable to slightly increasing in 

recent years. The Pacific Flyway’s portion of the populations have not 

shown the dramatic increases in white geese that have occurred in 

most other North American white goose populations (USFWS 2001). 

Despite both declines in waterfowl numbers and habitat, millions of 

waterfowl still concentrate in the Central Valley of California. The 

primary waterfowl use of the Refuges is by wintering ducks and 

geese, accounting for over 95 percent of all waterfowl use-days. 

Ducks breeding in areas to the north (mostly from Alaska and 

Western Canada) start migrating into the Sacramento Valley in 

August, and by early October, hundreds of thousands of both ducks 

and geese are present. Many birds arrive via the Klamath Basin, one 

of the most important migration staging areas in the Pacific Flyway 

(Gilmer et al. 2004). 

Presently, peak wintering numbers in California occur during late 

November through January, when 3-4 million ducks and over a 

million geese have been present in recent years (USFWS 1989-2007). 

For perspective, the four Refuges together have an average peak of 

over one million ducks and 300,000 geese. In some years, the four 

Refuges can exceed 1.5 million ducks and 300,000 geese (USFWS 

1989-2007). The most common wintering duck species include 

northern pintail, mallard, American wigeon, green-winged teal, 

gadwall, northern shoveler, and ring-necked duck (Table 7). The most 

common goose species include lesser snow, Ross’s, and Pacific and 

tule greater white-fronted geese. At certain times of the fall and 

winter, the majority of the Flyway’s portion of the population of 

Pacific greater white-fronted geese will be present on the four 

Refuges (USFWS 1985-2006; Trost 2006). Sacramento, Delevan, and 

Colusa Refuges comprise the core wintering area for tule greater 

white-fronted geese (Hobbs 1999). 

82 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Table 7. Regular waterfowl survey summary, early December, 2006. 

Refuge Sacramento Delevan Colusa Sutter TOTALS 

Coot 36,310 23,080 6,589 6,920 72,899 

White-fronted 

goose 29,836 32,410 15,980 29,800 108,026 

Snow/Ross’s 

goose 147,460 78,600 39,940 68,830 334,830 

Western Canada 

goose 30 160 0 0 190 

Cackling Canada 

goose 8 0 222 0 230 

Total Geese 177,334 111,170 56,142 98,630 443,276 

Mallard 42,576 28,928 5,955 11,265 88,724 

Pintail 426,060 169,780 32,478 41,540 669,858 

Gadwall 38,919 30,354 8,574 3,615 81,462 

Wigeon 50,595 59,810 24,426 8,725 143,556 

Green-winged 

teal 64,700 94,450 14,480 4,784 178,414 

Cinnamon teal 616 255 30 0 901 

N. shoveler 34,899 37,555 17,446 6,151 96,051 

Wood duck 2 0 64 352 418 

Total Dabbling 

Ducks 658,367 421,132 103,453 76,432 1,259,384 

Ring-necked 

duck 13,880 6,020 1,874 276 22,050 

Ruddy duck 7,360 4,950 39 280 12,629 

Bufflehead 273 390 184 191 1,038 

Canvasback 30 0 0 0 30 

other divers 0 0 0 2 2 

Total Diving 

Ducks 21,543 11,360 2,097 749 35,749 

Total All Ducks 679,910 432,492 105,550 77,181 1,295,133 

Comprehensive Conservation Plan 83 
Chapter 3 

Waterfowl use of the Refuges’ habitat varies by species and includes 

many other factors such as water depth, ratio of open water to 

emergent vegetation, food availability, access to loafing sites, level of 

human disturbance, and tradition. Over 95 percent of the waterfowl 

that occur on the Refuges are dabbling ducks and geese, which all 

prefer relatively shallow water. Only one to five percent are diving 

duck species, which prefer deeper water. Pintail, wigeon, greenwinged teal, shovelers, and other species prefer more open water, 

whereas mallards and gadwall will use wetlands with denser cover 

(Heitmeyer and Raveling 1988). 

Tule greater white-fronted goose 

Photo by Mike Peters 

Seasonally flooded wetlands (including watergrass units) contain 

abundant seeds and other vegetative food items (leaves, stems, 

tubers, etc.) produced from moist soil, and other aquatic plants, and 

invertebrates (insects, spiders, crustaceans, etc.). They are diverse in 

the amount and distribution of emergent vegetation (bulrushes, 

cattails) they provide, and also contain bare islands, levees, and open 

shorelines that provide excellent waterfowl loafing sites. Not 

surprisingly, the majority of wintering waterfowl select this habitat 

type above all other managed wetlands (Table 8). Waterfowl survey 

data collected on the Complex indicates that SFW can support up to 

three times the densities of semi-permanent wetlands and ten times 

that of permanent wetlands (M. Wolder, unpublished data). 

Vernal pools are also heavily used once they fill during the winter and 

spring, especially by mallards, wigeon, green-winged teal and 

shovelers (Bogiatto and Karnegis 2006; Silveira 1998). In addition, 

geese and wigeon will readily forage in alkali meadows and short 

grass uplands as soon as green browse is available in the fall (Silveira 

1998; USFWS 1989-2007). 

84 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

The Refuge Environment 

Table 8. Average duck densities (per acre with sample size 

in parentheses) by habitat type on managed wetlands at 

Sacramento Refuge Complex. 

Sacramento Delevan Colusa Sutter 

Permanent 

Pond 18.7 (272) 11.6 (105) 6.0 (408) 6.5 (13) 

Summer 

Water 42.9 (536) 30.6 (325) 16.7 (246) 28.7 (210) 

Watergrass 81.8 (358) 55.1 (225) 26.4 (71) 50.0 (144) 

Seasonally 

Flooded 

Wetland 46.8 (4192) 41.3 (1909) 23.0 (2345) 42.3 (960) 

The level of human activity plays a significant role in the distribution 

of waterfowl on the Refuges. Disturbance from auto tour routes, 

walking trails, hunting areas, and adjacent off-refuge activities can 

significantly affect bird use patterns (Purdy et al. 1987; Heitmeyer 

and Raveling 1988; Dahlgren and Korschgen 1992; Wolder 1993). For 

example, green-winged teal are particularly sensitive to human 

disturbance. Despite their overall significant numbers, they are very 

uncommon along auto tours and walking trails, tending to choose the 

most isolated areas within the sanctuaries (closed areas). Conversely, 

shovelers are less sensitive to disturbance relative to other species, 

and are more common in disturbed areas, including hunting areas 

(Heitmeyer and Raveling 1988). Other species tend to fall in the 

middle in terms of their sensitivity to human disturbance. Pintails, 

the most common waterfowl species on the Refuges, also showed 

strong differences in use patterns among units adjacent to auto tour 

routes, hunting units, and undisturbed units (Wolder 1993). Although 

hunting areas are readily used before and after the waterfowl 

hunting season, daytime use is much reduced during the hunting 

season compared to other Refuge units (Heitmeyer and Raveling 

1988; Wolder 1993). Waterfowl compensate for this, in part, by 

feeding at night in areas (i.e. hunting areas both on and off-Refuge) 

that are disturbed during the day. Waterfowl also tend to use denser 

habitats during the hunting season, presumably because they feel 

more secure due to the heavier vegetation that buffers both the sight 

and sounds of human activity (Heitmeyer and Raveling 1988; Wolder 

1993). 

Comprehensive Conservation Plan 85 
Tradition is a somewhat subjective factor of habitat use, and is most 

apparent with geese, especially with roosting sites. Some areas are 

used year after year by species, such as cackling geese and tule 

greater white-fronted geese. 

6.2. Breeding Waterfowl 

A small percentage of ducks remain through the spring and summer 

months to nest. An estimated 2,000 to 3,000 ducks are produced on 

the Refuges annually. Overall, the Central Valley is a significant 

breeding area for mallards (McLandress et al. 1996). In addition to 

production, wetlands on the Refuges also provide important postbreeding waterfowl molting areas (Yarris et al. 1994). 

Breeding waterfowl include (in order of most common to least 

common) mallard, cinnamon teal, gadwall, wood duck, western 

Canada goose, redhead, and ruddy duck. These species nest in a 

variety of uplands and wetlands. Most are ground-nesting species 

that nest in grasslands, drawn-down seasonal wetlands, or islands in 

semi-permanent and permanent wetlands. Redheads and ruddy 

ducks nest over water in permanent or semi-permanent wetlands. 

Wood ducks are exclusively cavity nesters, most nesting in humanmade wood duck boxes located along wooded canals or wetlands. 

Broods and molting birds of all species are primarily supported by 

semi-permanent and permanent wetlands. Some early broods take 

advantage of seasonal wetlands that are still in their spring 

drawdown phase. 

6.3. Shorebirds 

Shorebirds are present on the Refuges year-round, but as with most 

other migratory waterbirds, the greatest numbers are present during 

the non-breeding portions of the year. Surveys of the Central Valley 

in the mid-1990s indicated that the greatest numbers occur during 

winter and spring, when they are using a combination of flooded 

harvested rice fields and managed wetlands (Shuford et al. 1998). 

Shorebirds typically peak on the Refuges during spring as they pass 

Chapter 3 

Snow geese 

Photo by Steve Emmons 

86 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

through to their northern breeding grounds in the arctic tundra of 

Alaska. During this period, many of the Refuges’ seasonal wetlands 

and vernal pools provide abundant shallow habitat that the birds use 

to feed on aquatic insects and other invertebrates. During dry years, 

the Refuges can be particularly important for spring migrants based 

on habitat conditions in other parts of the Valley (Wolder et al. 1999). 

The most common migrants and wintering birds include western and 

least sandpipers, dunlin, long-billed dowitchers, long-billed curlews, 

and greater yellowlegs. A few birds will stay through the spring and 

early summer to breed on the Refuges, including killdeer, blacknecked stilts, and American avocets. 

Black-necked stilt and long-billed dowitchers. 

Photo by Mike Peters 

6.4. Wading/diving birds 

Many wading and diving birds are present on the Refuges yearround, utilizing several different habitats for foraging, roosting, and 

nesting. Great blue heron, great egret, and double-crested cormorant 

rookeries exist in riparian forests at Sacramento, Colusa, and Sutter 

Refuges. Other rookeries occur in summer wetlands, where species 

including white-faced ibis, snowy and cattle egrets, and blackcrowned night-herons nest in hard-stemmed bulrush and cattail 

patches. Other year-round species include American and least 

bitterns, green herons, Virginia rails, soras, common moorhens, 

American coots, and pied-billed and western grebes. American white 

pelicans can be present in significant numbers, but they do not breed 

in the Central Valley. 

White-faced ibis have been of particular interest because of their 

relatively recent increases in abundance. Extremely rare in the 

Sacramento Valley as of the 1970s, the white-faced ibis has increased 

dramatically, with significant breeding colonies and wintering birds 

on the Refuges. 

6.5. Gulls/terns 

Ring-billed and herring gulls are the most common gulls, occurring 

primarily during fall and into spring. Herring gulls can congregate on 

Comprehensive Conservation Plan 87 
Chapter 3 

the Refuges during winter waterfowl disease outbreaks, when they 

function as major scavengers. Forster’s and Caspian terns are often 

seen migrating in small numbers during the spring and fall. Black 

terns are present during the summer and nest in some areas of the 

Valley, including occasionally on Refuge wetlands. 

6.6. Birds of Prey 

Wide varieties of raptor species use the Refuges throughout the year. 

Breeding species include red-tailed, red-shouldered, and Swainson’s 

hawks, northern harriers, American kestrels, and common barn and 

great horned owls. Notably, a pair of golden eagles has nested at 

Sacramento Refuge annually since 1997. 

As with most of the other bird groups, overall raptor abundance is 

greatest in the winter. Raptors gather because of the abundant prey 

base of waterfowl, other wintering birds, and rodents. With the 

exception of Swainson’s hawks, all of the breeding species are also 

present during the winter in greater numbers, especially red-tailed 

hawks and northern harriers. Other regular wintering species include 

American bald eagle, turkey vulture, white-tailed kite, peregrine 

falcon, and Cooper’s hawks. Burrowing owls are a species of concern 

on the Refuges, as their numbers on the Complex have significantly 

decreased in the past 30 years. 

6.7. Game birds 

Upland game birds occupy various habitats on the Refuges. 

California quail, ring-necked pheasants, and wild turkeys are resident 

species that use a variety of grassland, riparian, and wetland habitats 

throughout the year. Grasslands 

are used for nesting and foraging, 

and riparian forest and wetlands 

provide roosting sites and escape 

cover. Mourning doves and 

Wilson’s snipe (a shorebird) are 

technically “migratory birds,” but 

are also classified as upland game 

birds in the California hunting 

regulations. Mourning doves occur 

year-round, as a common nester in 

riparian forest during the spring 

and summer, and a less common 

winter resident. Wilson’s snipe is 

primarily a migrant species and is 

most common in fall through spring 

in shallow wetlands. The only game 

birds hunted on the Refuges are 

snipe and pheasant. 

Wilson’s snipe 

Photo by Steve Emmons 

88 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

6.8. Other Landbirds 

The Refuges provide a variety of habitats for a great diversity of 

migratory and resident landbirds (Gilmer et al. 1998) (Appendix K). 

Habitat diversity, structural complexity, and proximity to wetlands 

are important habitat features. The Sacramento Valley is an 

important migration corridor that provides stopover resting and 

feeding habitat for landbirds that breed in the nearby foothills and 

mountains. It also contains important breeding and wintering area 

for a variety of migratory and resident songbirds and other 

landbirds. Many of these species are priority or focal species in 

conservation plans or on Federal or State priority species lists (Table 

9, Appendix K). 

One particular species of concern is the tricolored blackbird, a mainly 

California endemic species. These colonial birds nest in wetlands on 

the Refuges and feed in grasslands and seasonal wetlands. They will 

readily use upland areas grazed by livestock. Colonies periodically 

occur on all the Refuges and, in some years, Delevan Refuge has 

supported the largest nesting colonies in the state (Beedy et al. 1991; 

Hamilton 2004). Tricolors are likely itinerant breeders, with birds 

breeding in the San Joaquin Valley early in the season around April, 

then some moving up to the Sacramento Valley around late May to 

early June for another attempt (Hamilton 1998). 

Tri-colored blackbird 

Photo by Steve Emmons 

Non-native European starlings and house sparrows are common and 

often compete with native species for nesting sites. In addition, 

several native North American species whose populations have grown 

or expanded considerably, including American crow, common raven, 

and great-tailed grackle, are of concern because of their potential 

predation impacts on other species. 

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6.9. Mammals 

Many mammalian species are year-round residents of the Refuges. 

Wetlands and associated waterways support beaver, mink, river 

otter, and non-native muskrats. Other native species include the 

broad-footed mole, ornate shrew, big brown bat, Brazilian free-tailed 

bat, California myotis, Townsend’s big-eared bat, black-tailed 

jackrabbit, desert cottontail, California vole, deer mouse, Botta’s 

pocket gopher, California ground squirrel, western harvest mouse, 

coyote, long-tailed weasel, raccoon, striped skunk, and black-tailed 

deer. Non-native species include the Virginia opossum, black rat, 

Norway rat, house mouse, and feral house cat. 

6.10. Amphibians and 

Reptiles 

Reptiles are common residents on 

the Refuges, and include common 

and giant garter snakes, gopher 

snake, western yellow-bellied 

racer, California kingsnake, 

western fence lizard, western 

pond turtle, and red-eared slider 

(a non-native species). These 

reptiles mostly occur in upland 

habitats; however, the giant 

garter snake and western pond 

turtle are wetland-dependent 

species and occur commonly in 

permanent wetlands and canals. 

The Pacific treefrog and 

American bullfrog (a non-native 

species) are the only amphibians 

known to occur on the Refuges. 

Western pond turtles 

Photo by Mike Peters 

6.11. Fish 

Fish species occur at the Refuges throughout the water distribution 

system, which includes several creeks (Logan, Stone Corral, 

Hunter’s), the Colusa Basin Drain, east and west Sutter Bypass 

canals, and many smaller water supply and drainage ditches. These 

areas are all part of the Sacramento River system and share many of 

the same species (Appendix K). Most fish are non-native warm water 

resident species. Native anadromous fish include steelhead and four 

distinct runs of Chinook salmon. Three of the four Chinook salmon 

runs are considered unique Evolutionary Significant Units (ESU). 

These include the Sacramento River winter-run ESU, Central Valley 

spring-run ESU, and Central Valley fall-run and late-fall-run ESU 

Chinook salmon. The Central Valley ESU steelhead is also a unique 

race. Anadromous fish are migratory, using the open ocean, bays, 

estuaries, deltas, main river channels, floodplains, and tributaries. 

90 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Anadromous fish spawn in freshwater environments and spend their 

adult life in marine environments. 

During periods of high flows in the Sutter Bypass, large numbers of 

Chinook salmon and steelhead can use Sutter Refuge. Adult Chinook 

salmon and steelhead that spawn in Butte Creek pass through the 

Sutter Bypass to their spawning area in upper Butte Creek, while 

migrating juveniles pass through the Bypass to the Pacific Ocean. 

These fish typically pass through the Bypass during high water 

events within the east and west borrow channels, which are adjacent 

to Sutter Refuge. The Refuge maintains adequate flows of water 

through the wetland units within the Bypass for migrating juvenile 

salmonids during periods when these fish may be present. 

The above fish resources support a wide array of fish-eating birds 

and mammals, including pelicans, grebes, cormorants, bald eagles, 

osprey, and river otters. 

6.12. Invertebrates 

Invertebrates present on the Refuges are an important resource 

based on their contribution to biotic diversity and their vital function 

in the food chain for many fish and wildlife species. They occur in all 

habitat types, both aquatic and terrestrial. Some are abundant such 

as many species of midges, while others are quite rare, such as some 

vernal pool shrimp. A variety of endemic species occurs in vernal 

pool/alkali meadow habitats in association with endemic plant species. 

In combination with seeds and other vegetation, aquatic 

invertebrates are an essential part of many waterbird diets at various 

times of the year, as they provide a balance of amino and fatty acids 

to facilitate fat and protein storage (Euliss and Harris 1987; Miller 

1987; Heitmeyer and Raveling 1988). Invertebrates provide energy 

for migration, protein to replace molted feathers, and calcium for the 

production of eggs. Central Valley wetlands support a wide variety of 

aquatic invertebrates, including water fleas, snails, clams, 

dragonflies, damselflies, water boatmen, backswimmers, beetles, 

midges, mosquitoes, worms, clams, snails, crayfish, fairy shrimp, and 

various species of zooplankton (Severson 1987; Sefchick 1992; Lawler 

et al. 1997; Silveira 1998; Eriksen and Belk 1999). While many of 

these species larvae occur in the water column or sediment in 

wetlands, the adult stages are aerial and an important food source for 

landbirds and mammals, as well (i.e. swallows, flycatchers, and bats). 

Terrestrial invertebrates are also an important food base for many 

migratory and resident bird species, and include numerous species of 

grasshoppers, beetles, butterflies, moths, ants, spiders, and other 

insects. In addition, many of these invertebrates play key roles in 

plant pollination, including many rare and endemic species on the 

Refuges (Thorpe and Leong 1995). 

Comprehensive Conservation Plan 91 
Chapter 3 

Monarch butterfly caterpillar 

Photo by Joe Silveria 

6.13. Threatened and Endangered Species 

The Refuges provide breeding, rearing, migratory and/or wintering 

habitat for a number of Federal and State threatened and 

endangered species and species of special status. Listed species are 

presented in Table 9 and are summarized below. 

6.13.1. Palmate-bracted Bird's-beak 

Palmate-bracted bird's-beak (Federal and State-listed endangered 

species) is an annual herb in the snapdragon family. The plants are 4­

12 inches tall and highly branched. The stems and leaves are grayish 

green with small pale whitish flowers, 1⁄2-inch to 1 inch long, are 

arranged in dense clusters (spikes) and densely surrounded by 

herbaceous leaf-like bracts. Like other Cordylanthus species, the 

petals are divided into two lips. The upper one is shaped like a bird'sbeak, leading to the common name of the genus. Seedlings grow in 

late March or April. Flowers bloom from late spring through 

summer. Palmate-bracted bird's-beak is partially parasitic on the 

roots of other plants, including salt grass. 

Palmate-bracted bird's-beak grows on seasonally flooded, salinealkali soils in lowland plains and basins at elevations of less than 500 

feet (Mason 1957). Within these areas, it grows primarily along the 

edges of channels, drainages, and vernal pools with a few individuals 

scattered in seasonally wet depressions, alkali scalds (barren areas 

with a surface crust of salts) and grassy areas. 

92 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

 

 

 

 

 

 

The Refuge Environment 

Table 9. Federal and State listed species occurring or potentially occurring at 

Sacramento, Delevan, Colusa, and Sutter Refuges. 

Species Status Habitat Type Refuge 

Occurrence 

State Federal 

Plants 

Palmate-bracted bird’sbeak 

Cordylanthus 

palmatus 

CE FE vernal pool, 

alkali meadow 

SA, D, C 

Hairy Orcutt grass Orcuttia pilosa CE FE vernal pool SA, D, C 

Greene’s tuctoria Tuctoria greenei FE vernal pool SA, D, C 

Hoover’s spurge Chamaesyce 

hooveri 

FT vernal pool SA, D, C 

Colusa grass Neostapfia 

colusana 

CE FT vernal pool extirpated 

Invertebrates 

Conservancy fairy 

shrimp 

Branchinecta 

conservation 

FE vernal pool SA, D,C 

Vernal pool fairy shrimp Branchinecta 

lynchi 

FT vernal pool SA, D,C 

Vernal pool tadpole 

shrimp 

Lepidurus 

packardi 

FE vernal pool SA, D,C 

Fish 

Chinook salmon, Central 

Valley Spring.-run 

Oncorhynchus 

tshawytscha 

CT FT riverine 

floodplain 

SU 

Chinook salmon, 

Sacramento River 

Winter-run 

Oncorhynchus 

tshawytscha 

CE FE riverine 

floodplain 

SU 

Chinook salmon, Central 

Valley Fall/late Fall-run 

Oncorhynchus 

tshawytscha 

CS riverine 

floodplain 

SU 

Steelhead, Central Valley 

ESU 

Oncorhynchus 

mykiss 

FT riverine 

floodplain 

SU 

Amphibians & Reptiles 

Giant garter snake Thamnophis gigas CT FT wetlands, 

uplands 

All 

Birds 

Swainson's hawk Buteo swainsoni CT riparian forest, 

grasslands 

All 

Greater sandhill crane Grus canadensis 

tabida 

CT seasonal 

wetlands 

All 

Western yellow-billed 

cuckoo 

Coccyzus 

americanus 

occidentalis 

CE CS riparian forest SU 

Willow flycatcher Empidonax traillii CE riparian forest All 

Status Key: State of California: CE - State-listed, Endangered, CT - State-listed, Threatened 

Federal: FE - Federal-listed, Endangered, FT - Federal-listed, Threatened, CS – Candidate Species 

Refuge Occurrence: SA – Sacramento Refuge, D – Delevan Refuge, C – Colusa Refuge, SU – Sutter 

Refuge 

Bold indicates species has been observed on the Refuge and non-bold indicates suitable habitat is 

present. 

Comprehensive Conservation Plan 93 
Hairy Orcutt grass 

Photo by Joe Silveria 

Chapter 3 

Historically, the species is known from scattered locations in Fresno 

and Madera counties in the San Joaquin Valley, San Joaquin, Yolo, 

and Colusa counties in the Sacramento Valley and the Livermore 

Valley area of Alameda County. It is currently known to occur in 

seven locations in the Sacramento, Livermore and San Joaquin 

valleys. These include Sacramento, Delevan, and Colusa Refuges 

(Silveira 1992-2006a), the Woodland area, Springtown Alkali Sink 

near Livermore, western Madera County, and the combined Alkali 

Sink Ecological Reserve and Mendota Wildlife Management Area. 

The total occupied surface area over the seven locations is estimated 

at less than 741 acres (CFDG 2005a). Palmate-bracted bird’s-beak 

has been included in one of the first ecosystem recovery plans by the 

Service (USFWS 1998a). Populations on Delevan and Colusa Refuges 

currently comprise the majority of the entire population of this 

species. 

6.13.2. Hairy Orcutt Grass 

Hairy Orcutt grass (Federal and State-listed endangered species) 

inhabits vernal pools in rolling topography on remnant alluvial fans 

and stream terraces in the Central Valley. It is found on both acidic 

and saline-alkaline soils. It is a small (6-8 inches tall) annual in the 

grass family. Foliage is grayish with soft, straight hairs. Hairy Orcutt 

grass flowers from May through September. 

The historical range includes the eastern margins of Sacramento and 

San Joaquin Valleys from Tehama County south to Stanislaus County 

and through Merced and Madera counties. Only 27 of 40 historically 

known populations exist, including a new population in Merced 

County found in 2001 and a transplant population (CDFG 2005a). 

More than one third of the remaining populations occur in Tehama 

County. Others are in Butte, Glenn, Madera and Stanislaus counties. 

Populations of hairy Orcutt grass are found at the Sacramento 

Refuge in Glenn County (Silveira 1992-2006b). Conversion of vernal 

pool habitat to irrigated agriculture, vineyards, or orchards, or to 

urban uses has been the primary factor leading to the decline of this 

species (CDFG 2005a; USFWS 2005a). 

94 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

6.13.3. Greene's Tuctoria 

Greene's tuctoria (Federal-listed endangered species), which is also 

known as Greene's Orcutt grass, is a small, tufted annual in the grass 

family. The plant has several to many stems 2 to 6 inches tall, each 

ending in a spike-like inflorescence that may be partly enfolded in the 

upper leaf. 

The genus Tuctoria is distinguished from the closely related Orcutt 

grasses, by the spiral arrangement of the spikelets (flowers) and 

other characteristics of its flower parts. 

Greene's tuctoria is restricted to small or shallow vernal pools or the 

early drying sections of large, deep vernal pools in the Central Valley. 

Its historical range included parts of Shasta, Tehama and Butte 

counties in the northern Sacramento Valley, and extended from San 

Joaquin County to Tulare County in the San Joaquin Valley. About 

half of the approximately 40 known occurrences of Greene’s tuctoria 

have been extirpated through habitat conversion to irrigated 

agriculture and intensive cattle grazing (CDFG 2005a). The species 

apparently no longer occurs in Fresno, Madera, San Joaquin, 

Stanislaus, and Tulare counties. The remaining populations are in 

Shasta, southern Tehama, Butte, Glenn, and eastern Merced counties 

(USFWS 2005a). Populations of Green’s tuctoria are found on 

Sacramento Refuge. Refuge surveys (Silveira 1992-2006b) have not 

detected Greene’s tuctoria since 1996, a trend found throughout the 

species range. 

6.13.4. Hoover's Spurge 

Hoover's spurge (Federal-listed threatened species), also known as 

Hoover's sanmat, is a prostrate, tap-rooted, annual herb in the spurge 

family. It forms mats from a few inches to a few feet across. The 

flowering structure in Hoover's spurge has petal-like glands that are 

red to olive in color. Blooms appear in July. This species is readily 

distinguished from other species of Chamaesyce by characteristics of 

growth habit, plant color, and leaf shape. 

Hoover's spurge grows in relatively large, deep vernal pools among 

the rolling hills, remnant alluvial fans, and depositional stream 

terraces at the base of the Sierra Nevada foothills. It tends to occur 

where competition from other species has been reduced by prolonged 

seasonal inundation or other factors. The main remaining area of 

concentration for Hoover's spurge is in the northeastern Sacramento 

Valley. The Vina Plains of Tehama and Butte counties contains 14 

(53.8 percent) of the 26 known extant occurrences (USFWS 2005a). 

One other site in the same region is near Chico in Butte County. 

Seven of the extant occurrences are in the Southern Sierra Foothills, 

including five in the Visalia-Yettem area of Tulare County and two in 

the Hickman-La Grange area of Stanislaus County. Three other 

occurrences are on the Sacramento Refuge in Glenn County (Silveira 

Comprehensive Conservation Plan 95 
Chapter 3 

1992-2006b). The one other extant occurrence is on the Bert Crane 

Ranch in Merced County (USFWS 2005a). 

6.13.5. Colusa Grass 

This species has apparently been extirpated from Colusa County 

(USFWS 2005a). Historic accounts of this species (and its name) 

indicate that it likely occurred on or near Colusa, Delevan, and 

Sacramento Refuges. As a result, there is a possibility Colusa Grass 

could potentially still be present in small amounts. Monitoring of 

other rare endemic plant species on the Refuges indicate that there is 

a significant amount of variability in their occurrence from year to 

year and, in fact, certain species may not occur in some years or for a 

period of years (Silveira 1992-2006b). 

6.13.6. Conservancy Fairy Shrimp 

Conservancy fairy shrimp, vernal pool fairy shrimp, and vernal pool 

tadpole shrimp occur exclusively in vernal pool habitats that are 

flooded with rainwater. They occur as eggs in summer and fall dry 

periods, hatching and growing into breeding adults during their wet 

cycle following rain during winter and spring. Vernal pool habitat 

occurs at Sacramento, Delevan, and Colusa Refuges. 

The Conservancy fairy shrimp (Federal-listed endangered species) is 

a small crustacean that ranges in size from about 1⁄2 to one inch long. 

They have delicate elongate bodies, large stalked compound eyes, no 

carapaces, and eleven pairs of swimming legs. Conservancy fairy 

shrimp inhabit rather large, cool-water vernal pools with moderately 

turbid water (Eriksen and Belk 1999). The pools generally last until 

June. Female fairy shrimp carry their eggs in a ventral brood sac. 

The eggs are either dropped to the pool bottom or remain in the 

brood sac until the mother dies and sinks. When the pool dries out, so 

do the eggs. They remain in the dry pool bed until rains and other 

environmental stimuli trigger them to hatch. Resting fairy shrimp 

eggs are known as cysts. They are capable of withstanding heat, cold 

and prolonged desiccation. When the pools refill, some, but not all, of 

the cysts may hatch. The cyst bank in the soil may contain cysts from 

several years of breeding. Hatching can begin within the same week 

that a pool starts to fill. Average time to maturity is forty-nine days. 

In warmer pools, it can be as little as nineteen days (Eriksen and 

Belk 1999). 

The Conservancy fairy shrimp is currently known from several 

disjunct populations: the Vina Plains in Tehama County, south of 

Chico in Butte County; the Jepson Prairie Preserve and surrounding 

area in Solano County; Sacramento Refuge in Glenn County (Silveira 

2005); Mapes Ranch west of Modesto, San Luis Refuge, and the 

Haystack Mountain/Yosemite Lake area in Merced County; and two 

locations on the Los Padres National Forest in Ventura County 

(USFWS 2005a). 

96 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

6.13.7. Vernal Pool Fairy Shrimp 

The vernal pool fairy shrimp (Federal-listed threatened species) is a 

small crustacean that occupies a variety of different vernal pool 

habitats, from small, clear, sandstone rock pools to large, turbid, 

alkaline, grassland valley floor pools. Although the species has been 

collected from large vernal pools, including one exceeding 25 acres, it 

tends to occur in smaller pools. It is most frequently found in pools 

measuring less than 0.05 acre. These are most commonly in grass or 

mud bottomed swales, or basalt flow depression pools in unplowed 

grasslands. Vernal pool fairy shrimp have been collected from early 

December to early May. 

The vernal pool fairy shrimp is widespread but not abundant. Known 

populations extend from Stillwater Plain in Tehama County through 

most of the length of the Central Valley to Pixley National Wildlife 

Refuge in Tulare County. Along the central coast, they range from 

northern Solano County to Pinnacles National Monument in San 

Benito County. Four additional, disjunct populations exist: near Soda 

Lake in San Luis Obispo County; in the mountain grasslands of 

northern Santa Barbara County; in the Santa Rosa Plateau in 

Riverside County; and near Rancho California in Riverside County. 

Vernal pool fairy shrimp are found on Sacramento Refuge (Silveira 

2005). 

The vernal pool fairy shrimp was identified relatively recently, in 

1990. There is little information on its historical range. However, 

since it is currently known to occur in a wide range of vernal pool 

habitats, the historic distribution may have coincided with the historic 

distribution of Central Valley and Southern California vernal pools 

(USFWS 2005a). 

6.13.8. Vernal Pool Tadpole 

Shrimp 

The vernal pool tadpole shrimp 

(Federal-listed endangered 

species) is a small crustacean with 

compound eyes, a large shield-like 

carapace (shell) that covers most of 

the body, and a pair of long 

cercopods (appendages) at the end 

of the last abdominal segment. 

Vernal pool tadpole shrimp adults 

reach a length of 2 inches in length. 

They have about 35 pairs of legs 

and two long cercopods. This 

species superficially resembles the 

rice field tadpole shrimp. 

Vernal pool tadpole shrimp 

Photo by Joe Silveira 

Comprehensive Conservation Plan 97 
Chapter 3 

Tadpole shrimp climb or scramble over objects, as well as plowing 

along or within bottom sediments. Their diet consists of organic 

debris and living organisms, such as fairy shrimp and other 

invertebrates. This animal inhabits vernal pools containing clear to 

highly turbid water, ranging in size from 54 square feet in the former 

Mather Air Force Base area of Sacramento County, to the 89-acre 

Olcott Lake at Jepson Prairie in Solano County (USFWS 2005a). 

The life history of the vernal pool tadpole shrimp is linked to the 

seasonal cycle of the vernal pool. After winter rainwater fills the pool, 

the population is reestablished from cysts that lie dormant in the dry 

pool sediments. Sexually mature adults have been observed in vernal 

pools three to four weeks after the pools had filled. Some cysts hatch 

immediately and the others remain dormant in the soil to hatch 

during later rainy seasons. 

The vernal pool tadpole shrimp is known from eighteen populations in 

the Central Valley, ranging from east of Redding in Shasta County 

south to Tulare County, and from a single vernal pool complex on the 

San Francisco Bay Refuge in the City of Fremont, Alameda County 

(USFWS 2005a). Vernal pool tadpole shrimp are found on 

Sacramento Refuge (Silveira 2005). 

Sacramento Refuge is a Priority 1 recovery area for vernal pool 

tadpole shrimp, vernal pool fairy shrimp, Conservancy fairy shrimp, 

Hoover’s spurge, Green’s tuctoria, and hairy Orcutt grass, which are 

all included in the Recovery Plan for Vernal Pool Ecosystems of 

California and Southern Oregon (USFWS 2005a). 

6.13.9. Chinook Salmon, Sacramento River Winter-run ESU 

Chinook salmon, the Sacramento River winter-run ESU (Federal and 

State-listed endangered species), only occurs in the Sacramento 

River watershed in California and most spawning is limited to the 

main stem of the Sacramento River. Adult salmon leave the ocean 

and migrate through the Sacramento-San Joaquin Delta and 

upstream into the Sacramento River from December through July. 

Downstream migration of juvenile winter-run Chinook salmon occurs 

from November through May. They rear as fry along the entire 

Sacramento River and also migrate past the Refuge as smolts. 

Winter-run Chinook salmon can rear in the following areas on the 

Sacramento River: above Red Bluff Diversion Dam (moving 

downstream as smolts), and probably in the lower river between river 

mile 70 and 164 (moving downstream as fry). Water temperatures 

determine juvenile rearing locations and river conditions strongly 

influence movement. Critical Habitat for the Sacramento River 

winter-run Chinook salmon was designated June 16, 1993 (58 CFR 

33212, June 16, 1993). This species occurs on the Complex in Butte 

Creek, the east and west Sutter Bypass channels, and the 

Sacramento River. Winter-run Chinook salmon are monitored by the 

CDFG (2005b). 

98 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

6.13.10. Chinook salmon, Central Valley Spring-run ESU 

Chinook salmon, the Central Valley spring-run ESU (Federal and 

State-listed threatened species), occurs in the main stem of the 

Sacramento River and the Mill Creek, Deer Creek, Big Chico Creek, 

and Butte Creek tributaries. Adult salmon leave the ocean and 

migrate through the Sacramento-San Joaquin Delta, upstream into 

the Sacramento River from March through September. Downstream 

migration of juvenile spring-run Chinook salmon occurs from March 

through June, while yearlings move downstream from November 

through April. Most spawning occurs in headwater tributary streams. 

Critical habitat designation for this ESU is under development. This 

species occurs in the Butte Creek system, including the east and west 

Sutter Bypass channels. Spring-run Chinook salmon are monitored 

by the CDFG (2005b). 

6.13.11. Chinook salmon, Central Valley Fall-run ESU and 

Late-fall-run ESU 

Chinook salmon, the Central Valley fall-run ESU and late-fall-run 

ESU (Federal candidate species), occur in the main stem and 

tributaries of the Sacramento River. Adult fall-run salmon leave the 

ocean, migrate through the Sacramento-San Joaquin Delta, upstream 

into the Sacramento River from July through December, and spawn 

from October through December. Spawning occurs on the main stem 

of the Sacramento River, including below the Red Bluff Diversion 

Dam. 

Late-fall-run Chinook salmon occur on the main stem of the 

Sacramento River. Adult salmon leave the ocean, migrate through 

the Sacramento-San Joaquin Delta, upstream into the Sacramento 

River from October through April, and spawn from January through 

April. Spawning occurs above the Red Bluff Diversion Dam and lower 

tributaries of the middle and upper Sacramento River. This species 

occurs in the Butte Creek system, including the east and west Sutter 

Bypass channels. Fall-run and Late-fall-run Chinook salmon are 

monitored by the CDFG (2005b). 

6.13.12. Steelhead, Central Valley ESU 

Steelhead, the Central Valley ESU (Federal-listed threatened 

species), is an anadromous form of rainbow trout. This species has 

traditionally supported a major sport fishery in the Sacramento River 

system. Their historical range in the Central Valley has been reduced 

by dams and water diversions that now restrict the species to the 

lower portions of major rivers, where habitat is less favorable for 

steelhead spawning and rearing. Steelheads use the Sacramento 

River as a migration corridor to and from spawning grounds in the 

main stem of the river above the Red Bluff Diversion Dam, the 

tributary streams, and the Coleman National Fish Hatchery. They 

are present in the Sacramento River year-round, either as smolts 

migrating downstream or adults migrating upstream or downstream. 

Upstream migration begins in July, peaks in the fall, and continues 

Comprehensive Conservation Plan 99 
Chapter 3 

through February or March. Most spawning occurs from January 

through March. Juvenile migration generally occurs during the 

spring and early summer after at least one year of rearing in 

upstream areas. Populations have greatly declined over much of the 

species’ range, including the Sacramento River basin, due to blockage 

of upstream migration by dams and flood control projects, 

agricultural and municipal diversions, harmful temperatures in the 

Sacramento River, reduced availability of spawning gravels, and toxic 

discharges. Designation of river reaches as Critical Habitat is being 

considered for this ESU. This species occurs in the Butte Creek 

system, including the east and west Sutter Bypass channels. 

Steelheads are monitored by the CDFG (2005b). 

6.13.13. Giant Garter Snake 

The giant garter snake (GGS) (Federal-listed threatened species and 

State-listed threatened species) is an endemic species to the valley 

floors of the Sacramento and San Joaquin valleys (USFWS 1999a). 

Although the boundaries of its original distribution are uncertain, 

giant garter snakes probably historically occurred from Butte County 

in the north, southward to Buena Vista Lake in Kern County 

(USFWS 1999a). The present distribution is from Chico to central 

Fresno County. Loss, degradation, and fragmentation of habitat are 

the primary threats to the giant garter snake. Conversion of wetlands 

for agriculture and urban and industrial development has resulted in 

the loss of more than 90 percent of suitable habitat for this species in 

the Central Valley (CDFG 2005a). 

Giant garter snake 

Photo by Gary Kramer 

The GGS requires freshwater wetlands, such as marshes and low 

gradient streams. Permanent wetlands are of particular importance, 

as they provide habitat over the summer and early fall, when seasonal 

wetlands are dry. The GGS also inhabits rice fields, irrigation and 

drainage canals, sloughs, ponds, small lakes, low gradient streams, 

and adjacent uplands in the Central Valley. 

The Service prepared a draft Recovery Plan for this species in 1999. 

The plan identified four recovery units within the range of the giant 

100 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

garter snake (Sacramento Valley, Mid-Valley, San Joaquin Valley, 

and South Valley) and proposes recovery criteria. The recovery 

criteria include adaptive management and monitoring; successful 

reintroduction within the historic range of the species; documentation 

of successful breeding and survivorship in 90 percent of the 

subpopulations in the recovery units; and maintenance of connectivity 

between subpopulations. 

GGSs occur in significant numbers on all of the Refuges, except for 

Delevan Refuge. Intensive monitoring efforts by U.S. Geological 

Survey (USGS) between 1996 and 2005 indicated thriving populations 

particularly at Colusa and Sacramento Refuges (Carpenter 1999; 

Wylie et al. 2006). These investigations also documented a positive 

response from GGS to wetland restoration and management on 

Colusa Refuge, including increased Refuge populations, decreased 

exposure to mortality factors, and reduced home range size (Wylie et 

al. 2006; USFWS 1999a). The size distributions of snakes caught 

reflect a healthy population of GGSs, with successful recruitment of 

young. 

6.13.14. Swainson’s Hawk 

Swainson’s hawks (State-listed threatened species) breed in North 

America and winter in Mexico, Central America, and South America. 

In California, this species may have declined by as much as 90 

percent (RHJV 2004). Swainson’s hawks were once found throughout 

the lowland in California and were absent only from the Sierra 

Nevada, north Coast Ranges and Klamath Mountains, and portions of 

the desert regions of the State. Today, they are restricted to portions 

of the Central Valley and Great Basin regions where suitable nesting 

and foraging habitat is still available (CDFG 2005a). 

Approximately 95 percent of the California Swainson’s hawks exist in 

the Central Valley (CDFG and UC Davis 2006). Swainson’s hawk 

nesting and foraging has been documented on or very near all of the 

Refuges. They nest in trees along riparian corridors, or in isolated 

trees or small groves, near suitable foraging habitat. Foraging 

habitat consists of grassland vegetation and short herbaceous 

croplands. 

About 80 percent of the Central Valley population is located in 

Sacramento, San Joaquin, and Yolo counties. During historical times 

(ca. 1900), Swainson's hawks may have maintained a population of 

more than 17,000 pairs. Based on a study conducted in 1994, the 

statewide population was estimated to be approximately 800 pairs. 

The current status of the Swainson’s hawk in California is declining 

(CDFG 2005a). 

Comprehensive Conservation Plan 101 
Chapter 3 

6.13.15. Greater Sandhill Crane 

The greater sandhill crane (State-listed threatened species) is the 

largest of the six subspecies of sandhill cranes. They breed north and 

east of the Central Valley as far north as British Columbia. The 

Central Valley is the cranes’ primary wintering area, characterized 

by favorable roost sites and an abundance of cereal grain crops. Rice 

is used extensively by cranes in the northern Sacramento Valley and 

corn is the principal food source at most other Central Valley 

wintering areas. Irrigated pastures are used for feeding and roosting 

sites throughout the wintering ground. Communal roost sites 

consisting of open expanses of shallow water are key features of 

wintering habitat. 

Currently, the estimate for 

greater sandhill cranes within 

their Pacific Flyway range is 

between 5,000 and 6,000 (CDFG 

2005a). This species continues to 

experience threats on both 

wintering and breeding grounds 

due to agricultural and urban 

conversion of habitat, predation, 

human disturbance, and collisions 

with power lines. Sandhill cranes 

have been documented on all of 

the Refuges. 

Greater sandhill crane 

Photo by Steve Emmons 

6.13.16. Western Yellow-Billed Cuckoo 

The western yellow-billed cuckoo (Federal candidate species, Statelisted threatened species) requires dense, large tracts of riparian 

woodlands with well-developed understories for breeding. Cuckoo’s 

nest in larger trees, such as Fremont’s cottonwoods, located in close 

proximity to foraging habitat (mixed riparian forest and willow and 

herbaceous scrublands). Their breeding range in California includes 

the lower Colorado, Kern, and Sacramento rivers. 

The western yellow-billed cuckoo is threatened by loss and 

degradation of its habitat due to land clearing, fire, flood control 

projects, surface water diversions and groundwater pumping, and 

overgrazing by livestock (CDFG 2005a). Such disturbances often 

foster the establishment of invasive non-native plants, such as 

tamarisk and giant reed. The resulting fragmentation reduces the 

size and quality of habitat for the cuckoo. 

The current population in California is about 60 to 100 pairs 

(Halterman et al. 2001). A statewide survey of yellow-billed cuckoos 

in California conducted during 1986 and 1987 found a total of 30 to 33 

102 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

pairs and 31 unmated males at nine localities (Laymon and 

Halterman 1989). The majority of the cuckoos were concentrated 

along the upper Sacramento River from Red Bluff to Colusa (18 pairs 

and 19 unmated males) and at the South Fork Kern River (7 pairs 

and 3 unmated males) (Laymon 1998). Cuckoos were located at 

Sutter Refuge and other nearby areas during recent surveys 

conducted in 1999 to 2000 (Isola 2000). 

7. Fish and Wildlife Management 

Fish and wildlife management on these Refuges is mostly 

accomplished through habitat management, restoration, and 

enhancement. Habitat restoration and management can improve the 

overall health and productivity of fish and wildlife populations by 

increasing water, food, breeding, staging, winter areas, cover and 

shelter. Habitat and management needs can be designed to benefit 

certain target species or, more commonly, multiple species. 

7.1. Migratory Bird Management 

One of the Refuges’ primary purposes is to provide habitat for 

migratory birds, particularly wintering waterfowl. The habitat 

management described in the Habitat Section (Section 4) contributes 

to achieving that purpose. The combination of managed habitat types 

support annual peaks of 1.5 to 2 million wintering ducks and geese, 

50,000 shorebirds during spring migration, a large contingent of 

raptors, and a variety of other migratory birds. In addition, these 

habitats support a significant number of breeding and migratory 

birds, including a variety of waterfowl, grebes, herons, egrets, 

bitterns, white-faced ibis, coots, moorhens, rails, marsh wrens, 

blackbirds, and others. 

The Refuges coordinates and/or participates in a number of 

migratory bird surveys and monitoring projects throughout the year. 

Depending on the survey, these efforts are used for monitoring 

migratory birds at the Refuge, Valley, State, Pacific Flyway, or 

national level. They include aerial and ground migratory bird 

surveys, 

evaluation of 

annual arctic 

goose productivity 

(age ratios), 

waterfowl 

banding, breeding 

bird surveys, and a 

number of other 

special surveys 

conducted for 

species of concern 

(Table 10). Waterfowl banding 

Photo by Mike Carpenter 

Comprehensive Conservation Plan 103 
Chapter 3 

Table 10. Migratory bird surveys and other monitoring efforts currently conducted 

by Sacramento Refuge Complex staff1. 

Survey/ 

Monitoring 

Effort Species 

Time of Year/ 

Frequency Geographic Area Purpose 

Agency 

Coordination2 Product 

Regular 

Wildlife 

Most Waterbirds/ 

Raptors 

Sep.-April – 

monthly; MayAugust -

bimonthly 

All Refuges 

Monitor Refuge 

numbers, distribution, 

and habitat use 

USFWS summary 

reports 

Tule greater 

white-fronted 

goose direct 

Tule greater 

white-fronted 

goose 

September/ 

annual 

Sacramento NWR 

Complex monitor PF3 numbers USFWS, CDFG summary 

report 

Tule greater 

white-fronted 

goose indirect 

Tule greater 

white-fronted 

goose 

Fall-Winter/ 

annual 

Sacramento NWR 

Complex monitor PF numbers USFWS, CDFG summary report 

Special 

Whitefront 

all greater whitefronted geese October/ 

annual Sacramento Valley monitor PF numbers/ distribution USFWS, CDFG summary report 

Aleutian 

Canada Goose 

Aleutian Canada 

goose 

Fall-Spring/ 

annual 

Sacramento NWR 

Complex and vicinity 

monitor PF numbers/ 

distribution USFWS summary report 

Special Dark 

Goose 

all white-fronted 

geese, all Canada 

geese 

November/ 

annual Sacramento Valley monitor PF numbers/ distribution USFWS, CDFG summary report 

Special White 

Goose 

lesser snow 

goose, Ross’s 

goose 

December/ 

annual Sacramento Valley monitor PF numbers/ distribution USFWS, CDFG summary report 

White Goose 

Species 

Composition 

lesser snow 

goose, Ross’s 

goose 

December/ 

once every 3 

years 

Sacramento Valley 

determine proportions 

of snow and Ross’s 

geese in overall "white 

goose" population 

USFWS, CDFG summary 

report 

Mid-winter 

Waterfowl 

Index 

All waterfowl January/ 

annual Sacramento Valley monitor PF numbers/ distribution USFWS, CDFG summary report 

Breeding Bird 

Survey-Orland 

Route 

all birds June/ annual specified route in 

Glenn County 

monitor national bird 

trends USGS USGS report 

Special surveys 

for colonial 

birds 

white-faced ibis, 

herons/egrets, 

cormorants 

May-August/ 

variable based 

on occurrence 

Sacramento NWR 

Complex 

monitor reproductive 

effort and success on 

Refuges 

USFWS summary 

report 

Special Tricolored 

Blackbird 

tri-colored 

blackbird 

April-August/ 

no set 

schedule 

Sacramento NWR 

Complex 

monitor state numbers/ 

distribution, 

reproductive effort and 

success 

USFWS, CDFG, 

PRBO, various 

other participants 

state 

summary 

report 

Arctic Goose 

Productivity 

tule white-fronted 

goose, pacific 

white-fronted 

goose, lesser 

snow goose, 

Ross’s goose 

Fall/ annual Sacramento NWR 

Complex and vicinity 

monitor annual 

productivity USFWS Flyway 

Report 

Waterfowl 

Banding 

mallard, other 

waterfowl banded 

incidentally 

summer/ 

annual 

Sacramento NWR 

Complex 

monitor PF survival 

and harvest rates USFWS Flyway 

Report 

Resighting 

Marked Birds1 

various 

waterfowl, 

shorebirds, or 

other waterbirds 

variable Sacramento NWR 

Complex and vicinity 

indirect numbers 

estimates, survival 

rates, habitat use, 

migration patterns, etc. 

USFWS, USGS, 

CDFG, CWA, 

PRBO, various 

universities, and 

others 

various 

1

 Includes surveys that Refuge conducts, coordinates, facilitates, or otherwise participates in. 2

 CDFG=California Department of Fish and Game, USGS=U.S. Geological Survey, CWA=California Waterfowl Association, PRBO=Point 

Reyes Bird Observatory. 

3 PF=Pacific Flyway. 

104 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

7.2. Threatened and Endangered Species Management 

Sacramento, Delevan, Colusa, and Sutter Refuges provide habitat for 

a number of threatened, endangered, and sensitive species that occur 

across a variety of habitat types (Table 9, Appendix K). Management 

activities for these species and their habitats include vegetation 

manipulation (i.e. burning, grazing, etc.), population monitoring, and 

research efforts that are implemented through the same annual 

habitat management planning (AHMP) process as other biological 

resources (see Section 4). Any special requirements are considered 

and documented in the AHMP. Management of these habitats are 

low-impact, but typically not “hands-off,” and often include periodic 

treatments of burning or grazing, implementation of best 

management practices (BMPs) to reduce frequency of disturbance, 

and emphasize the restoration of natural processes, particularly 

hydrology and the minimization of mechanical soil disturbance. 

Certain management activities beneficial to some species or habitats 

may negatively impact others. Because of the many management 

activities that regularly occur here, the Complex has consulted with 

Ecological Services on operations and maintenance activities of the 

Refuges to ensure that their implementation complies with the 

Endangered Species Act. The resulting biological opinion stated 

these activities would not jeopardize the continued existence of any 

federally-listed endangered or threatened species on the Complex 

(USFWS 1999d). Part of the opinion recommends BMPs for working 

in or near sensitive habitats, monitoring, and providing annual 

reports of activities. As required by Service policy, the Refuges also 

incorporate State-threatened and endangered species into planning 

activities. 

American avocets 

Photo by Steve Emmons 

Comprehensive Conservation Plan 105 
Chapter 3 

7.3. Game Management 

Game species commonly occurring on the Refuges include wild 

turkeys, ring-necked pheasants, various waterfowl species, and 

Wilson’s snipe. The only game species hunted on the Refuges are 

waterfowl, snipe, and pheasant. Other than waterfowl, game species, 

are not managed for explicitly. However, upland game species receive 

incidental benefits from the habitats that are managed for other 

priority Refuge resources. For example, uplands, seasonal marshes, 

and summer wetlands all contribute to nesting cover for upland game 

birds. Well-distributed summer wetlands (semi-permanent and 

permanent) provide essential water sources during summer months, 

when the Refuges are relatively dry. Pheasant brood production is 

monitored annually on Sacramento, Delevan, and Colusa Refuges. 

Results provide an index to track the production of pheasants and 

other ground nesting birds, and can be related back to harvest 

information from Refuge hunting areas. Turkeys are monitored 

through regular wildlife surveys. 

Ring-necked pheasant 

Photo by Steve Emmons 

7.4. Monitoring, Research, and Investigations 

Monitoring and research projects are conducted by refuge biological 

staff or cooperatively with principle investigators from government 

agencies, universities, and private conservation organizations. 

Monitoring and research are the foundation for Refuge management 

decisions. At the Refuge level, a number of biological surveys are 

conducted to determine and track the distribution and abundance of 

biological resources and their use of Refuge habitats. The Refuges’ 

regular wildlife surveys are the cornerstone of these surveys. They 

are conducted by ground vehicle on standardized routes for each 

Refuge. Species and numbers of waterfowl and other waterbirds, 

raptors, and other birds and mammals that can be seen readily are 

estimated and recorded for each Refuge unit. This level of data 

collection allows for the evaluation of wildlife use by habitat type, 

management treatment, and type and level of visitor services (i.e. 

auto tour, hunt area, walking trail, etc.). 

106 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

This information is stored, tracked, and analyzed in a database and 

used to develop annual habitat management plans, where projects 

designed to rehabilitate, enhance, and restore wildlife habitat are 

identified, prioritized, and project implementation is tracked and 

management actions are evaluated. 

In addition, special surveys are conducted for a variety of rare or 

special status species or species of management concern. Examples 

include surveys for endemic vernal pool plants and invertebrates and 

various migratory birds. 

Study proposals are evaluated by refuge staff to assure that the 

research is compatible with the Refuge and that some aspect of the 

results will contribute to wildlife and habitat management. A Special 

Use Permit (SUP) is issued to each research investigator. The SUP 

identifies and describes individual projects, provides contact 

information, identifies where research activities will take place, and 

describes special conditions to assure the health and safety of the 

environment and those who visit the Refuges. Because of the number 

of researchers that may be working on the Refuges at any one time, 

coordination among the projects and with normal Refuge operations 

is essential. Researchers have come from universities such as 

California State University Chico, the University of California (UC) 

Berkeley, UC Davis, UC Santa Cruz, and the University of Denver. 

Federal and State agencies such as the U.S. Geological Survey 

(USGS), USFWS, California Department of Water Resources, and 

CDFG also conduct research on the Refuges. Researchers investigate 

a wide range of biological and physical phenomenon. These include 

topics on wildlife biology (distribution/abundance, reproductive 

success, predation, and impacts from contaminants), vegetation 

analysis (growth rates, species composition, succession, and exotic 

species impacts), water quality, soils analysis, and hydrology. 

7.5. Wildlife Disease Monitoring and Treatment 

Because the Refuges are a concentration area for migratory birds 

and other wildlife, there is elevated potential to have significant 

disease outbreaks and mortality events. Historic disease losses on the 

Refuges are described in the Waterfowl Disease Contingency Plan 

(Appendix H). 

Avian botulism (Type C) and avian cholera are the two most common 

wildlife diseases that affect migratory birds at the Refuges. Botulism 

is generally a warm weather disease that usually occurs between July 

and October. Botulism spores from the bacteria Clostridium 

botulinum occur naturally in wetlands and can reproduce under the 

right environmental conditions, including low oxygen levels and warm 

temperatures (Sandler et al. 1993; Rocke and Samuel 1999). These 

bacteria produce a powerful neurotoxin that affects the central 

nervous system of waterfowl and other waterbirds resulting in 

paralysis and eventually death. During warm months, the disease can 

Comprehensive Conservation Plan 107 
 

Wildlife disease monitoring 

Photo by Jackie Ferrier 

Chapter 3 

be spread rapidly through a carcass-maggot cycle where maggots 

that have fed on carcasses concentrate botulism toxin in their bodies 

and then are consumed readily by other birds, leading to their demise 

(USGS 1999). Outbreaks during winter or spring months are possible, 

but much less common and less severe in terms of mortality. 

Avian cholera is typically a cold weather disease that typically occurs 

between the months of November and March. With cholera, the 

bacteria Pasturella multocida infects and directly attacks birds’ 

internal organs and respiratory system. Recent studies indicate that 

cholera does not persist long in the environment (Samuel et al. 2004). 

Outbreaks are more likely started via carrier birds and transmitted 

primarily bird-to-bird (Mensik and Samuel 1995; Samuel et al. 1999). 

While a wide variety of other wildlife diseases have been documented 

or could potentially occur on the Refuges, botulism and cholera 

account for the majority of disease management operations. 

In the last decade, annual mortality from botulism and cholera in the 

Sacramento Valley has decreased and may be related to restoration 

efforts and increases in waterfowl habitat in the Central Valley 

(Eddings and Eadie 2003). 

Other diseases of concern that have not yet been detected or have not 

been documented to affect many animals at the Refuges include West 

Nile Virus, Chronic Wasting Disease, and Duck Viral Enteritis. 

Since 2005, there have been increasing concerns about highly 

pathogenic Asian H5N1 avian influenza reaching North America 

from Asia or Europe, possibly via inter-Flyway movements of 

migratory birds. Because of the potential of this disease to affect 

people, surveillance of migratory birds and their habitats for this 

disease has increased significantly as of 2005 (Interagency Asian 

H5N1 Early Detection Working Group 2006; Pacific Flyway Council 

2006; CDFG et al. 2006). Because of the Refuges’ concentration of 

108 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

waterfowl, a number of Federal and State surveillance efforts 

continue to be facilitated here. 

Avian flu testing 

CDFG Photo 

Lead poisoning, although technically not a disease, is observed 

annually on Refuges. Prior to the conversion to non-toxic shot in the 

late 1980s, lead pellets from spent shotgun shells were deposited 

annually in wetlands where hunting occurred. Research studies in the 

late-1980s documented site-specific lead ingestion in mallards on the 

Sacramento Refuge (Rocke et al. 1997). Conversion to non-toxic shot 

began on Refuges in 1986. Gizzard collections on the Refuges from 

1986 through 1995 documented a decrease in lead ingestion rates, and 

a corresponding increase in steel or other non-toxic shot ingestion 

rates (Table 11). While this trend was occurring, other studies 

identified the continued exposure of waterfowl to lead poisoning on 

Complex Refuges (Mauser et al. 1990; Rocke et al. 1997). Resulting 

research documented methods of habitat management designed to 

address an accumulated lead problem on certain Refuge wetland 

units (Thomas et al. 2001). In summary, today lead poisoning appears 

far less frequently in waterfowl using the Refuges’ wetland habitats. 

These results are consistent with other refuges in the Pacific Flyway 

(Table 12), as well as other parts of the United States (Anderson et al. 

2000). 

Comprehensive Conservation Plan 109 
Chapter 3 

Table 11. Comparison of lead and steel shot ingested by hunter-shot mallards at 

Sacramento Refuge. 

LEAD STEEL 

Year Number 

with 

Ingested 

Shot 

Number 

with Shot 

(%) 

Number 

with 1 

Shot (%) 

Number 

with 2+ 

Shot (%) 

Number 

with 

Shot (%) 

Number 

with 1 

Shot (%) 

Number 

with 2+ 

Shot (%) 

1975-761 400/46 46 (11.5) NA2 NA - - -

1976-77 454/29 20 (6.4) 22 (4.8) 7 (1.5) - - -

1979-80 110/8 8 (7.3) NA NA - - -

1980-81 200/15 15 (7.5) 9 (4.5) 6 (3) 0 - -

1987-88 101/6 1 (1) 1 (1) 0 5 (5) 5 (5) 0 

1988-89 164/3 0 0 0 3 (1.8) 3 (1.8) 0 

1989-90 163/7 3 (1.8) 2 (1.2) 1 (0.6) 4 (2.5) 3 (1.8) 1 (0.6) 

1990-91 130/2 1 (0.8) 1 (0.8) 0 1 (0.8) 1 (1.8) 0 

1991-92 130/6 1 (0.8) 0 1 (0.8) 5 (3.8) 5 (3.8) 0 

1992-93 173/9 3 (1.7) 3 (1.7) 6 (3.5) 2 (1.2) 4 (2.3) 

1993-94 290/16 6 (2.1) 6 (2.1) 2 (0.7) 11 (3.8) 8 (2.8) 3 (1) 

1994-95 137/10 3 (2.2) 3 (2.2) 1 (0.7) 7 (5.1) 4 (2.9) 3 (2.2) 

1 Includes Sacramento, Delevan, and Colusa Refuges and Gray Lodge WMA 

2 Information not available 

Table 12. Comparison of lead and steel shot ingested by hunter-shot mallards at 

Sacramento, Tule Lake, and Ridgefield Refuges. 

1994-95 Mallard Lead/Steel Shot Ingestion Summary 

Refuge Number 

of 

Gizzards 

Examined 

Number 

with 

Ingested 

Shot 

Number 

with 

Lead 

Number 

with 1 

Lead 

Shot 

Number 

with 2+ 

Lead 

Shot 

Number 

with 

Steel 

Number 

with 1 

Steel 

Shot 

Number 

with 2+ 

Steel 

Shot 

Sacramento 

NWR 

137 10 

7.3% 

3 

2.2% 

2 

1.5% 

1 

0.7% 

7 

5.1% 

4 

2.9% 

3 

2.2% 

Tule Lake 

NWR 

104 21 

20.20% 

9 

8.7% 

7 

6.7% 

2 

17.3% 

18 

17.3% 

7 

6.7% 

11 

10.6% 

Ridgefield 

NWR 

116 41 

35.30% 

13 

11.2% 

6 

5.2% 

7 

6.0% 

36 

31% 

20 

17.2% 

16 

13.8% 

110 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Wildlife disease monitoring is conducted regularly throughout the 

year. Wetland units and other areas are inspected regularly and 

opportunistically for dead or sick animals while conducting other field 

work. During months of greater outbreak probability, some wetland 

units with notable disease histories are surveyed via airboat to detect 

any problems early. During outbreaks, dead birds are located and 

removed using airboats to systematically cover all areas within a unit. 

Standard safety precautions are followed when picking up carcasses 

or conducting other disease surveillance (USGS 1999; USFWS 2006). 

Monitoring includes documentation by unit for number and condition 

of dead and sick animals, tracking of effort, and shipment of 

diagnostic specimens to the USGS National Wildlife Health Center, 

in Madison, Wisconsin, where the carcasses are necropsied and 

tested to confirm the cause of death (USGS 1999). Other carcasses 

may be saved for scientific or educational activities or incinerated. 

When appropriate, results are shared with other Service divisions 

(Law Enforcement, National Forensics Laboratory at Ashland, 

Oregon) and CDFG (game wardens, Wildlife Investigations 

Laboratory at Rancho Cordova). 

8. Visitor Services 

8.1. Visitor Services and Management Policy 

There are a variety of sources for policy and guidance to manage 

visitor service programs on Refuges. The Service Manual (605 FW 1­

7) provides the policy for wildlife-dependent recreation including 

hunting, recreational fishing, wildlife observation, wildlife 

photography, environmental education, and interpretation. The policy 

also provides guiding principles for each of the wildlife-dependant 

recreation programs. 

Entrance sign at Sacramento Refuge 

USFWS photo 

In October 1984, the Service published “National Public Use 

Requirements” to help field stations, including refuges, to plan, 

implement, and evaluate public use programs. The established 

requirements are: set public use goals, project a positive attitude, 

Comprehensive Conservation Plan 111 
Chapter 3 

welcome and orient visitors, develop key resource awareness, provide 

observation opportunities, maintain quality hunting program, 

maintain a quality fishing program, and provide public assistance. 

In 2007, the Service declared that “connecting people with nature” is 

among the agencies highest national priorities (USFWS 2008). A 

connection with nature, whether it’s hiking, fishing, camping, hunting, 

or simply playing outside, helps children develop positive attitudes 

and behaviors towards the environment. Positive interactions with 

the environment can lead to a life-long interest in enjoying and 

preserving nature. People’s interest in nature is crucial to the Service 

mission of conserving, protecting, and enhancing fish, wildlife, plants, 

and their habitats. 

When Service employees were asked to describe a childhood 

experience where they felt a connection with nature, the answers 

ranged from memories of riding on the laps of loved ones while 

mowing the lawn, to family vacations along a lake, beach, or forest, to 

hiking, climbing trees, and discovering insects, frogs, and birds. 

Many employees credit these memorable moments for placing them 

in the career that they are in today. Those experiences were the 

spark that led to a lifetime of stewardship and conservation. The 

Service wants to capture that spark and share it with the next 

generation of conservationists. The Connecting People with Nature 

Program goals for Region 8 include 1) Rekindle the spark, 2) Share 

the spark and 3) Ignite the spark. Currently, these goals are being 

implemented on the Refuges. 

A Visitor Services Plan for the Refuges is included in Appendix D. 

8.2. Trends 

The ability to compare and analyze population and demographic 

trends is invaluable in making projections about future recreational 

needs, as well as for assessing existing visitor facilities and programs. 

The following are highlights of some recreation reports and surveys 

that are available for consideration when managing the visitor 

services program. 

The Public Opinions and Attitudes on Recreation in California report 

(California Department of Parks and Recreation 2003) surveyed 

public attitudes, opinions, and values regarding key areas of interest 

relating to outdoor recreation opportunities in California; and public 

participation interests in different types of outdoor recreation 

activities. The results of this study on the public opinions and 

attitudes about outdoor recreation in California are in general 

agreement with past editions of this study. Californians think outdoor 

recreation areas and facilities are very important to their quality of 

life (84.1 percent), and more than two-thirds (69.1 percent) reported 

spending the same or more time in outdoor recreation activities then 

five years ago. Almost all Californians (96.7 percent) agreed or 

112 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

strongly agreed that maintaining the natural environment in outdoor 

recreation areas was important to them. The most important factors 

influencing enjoyment of recreational activities were being able to 

relax (75.9 percent), feeling safe and secure (68.3 percent), being in 

the outdoors (75.9 percent), beauty of the area (61.8 percent), and 

meeting new people (13.2 percent) ranked last. 

Three priority wildlife-dependent activities were surveyed and 

ranked in this report (Table 13), although it should be noted that the 

nature study category could also include educational and interpretive 

activities. Walking for fitness and fun was ranked number one with 

91.1 percent participating in an average 94.4 days per year. Driving 

for pleasure, sightseeing, and driving through natural scenery ranked 

second with 90.2 percent (31.3 days). Windsurfing showed the lowest 

percentage participation (3.4 percent), with snowmobiling and 

orienteering/geo-caching tied for next lowest (4.6 percent). Fifty 

percent or more of the respondents participated in 11 of the 55 

recreation activities at least one day during the 12 months prior to 

the survey. 

Table 13. Ranks of three wildlife dependent activities (California 

Department of Parks and Recreation 2003). 

Rank Participation Average 

Number of 

Days 

Participated 

Wildlife viewing, 

bird watching, 

viewing natural 

scenery 

8 75.1% 25.3 

Fishing 

(freshwater) 

19 34.0% 5.8 

Hunting 49 9.0% 1.9 

The Park and Recreation Trends in California 2005 report 

summarizes the State’s population and demographic trends affecting 

parks, recreation areas, programs and services (California State 

Parks 2005). Some of the highlights include: 

 California’s population is currently 34 million and will 

increase 1⁄2 million persons annually. 

 California is continuing to be more culturally and racially 

diverse – Asians and Hispanics are the top two groups. 

 California’s senior population will double by 2010. 

 Baby boomers (40-60 years) are reaching retirement age, 

adding to the citizen-steward group. 

 Today’s youth (18-40 years) are the most urban of any 

generation, seeking one-day excursions with multiple 

activities. 

Comprehensive Conservation Plan 113 
Chapter 3 

 Understanding how people recreate will be the most effective 

way to serve visitors. 

 California’s advanced technology and transportation will 

expand recreational opportunities. 

 Favorite outdoor recreation activities, pertinent to refuges 

that will continue to dominate include walking, picnicking, 

sightseeing, and visiting nature centers. 

 Day hiking, bicycling, running, and wildlife viewing are 

predicted to increase in popularity. 

 Educational and interpretive programs will continue to be 

essential to help visitors understand the relationship between 

humans, nature and cultural heritage. 

Recreation trends in the U.S. are found in Outdoor Recreation in 

American Life: A National Assessment of Demand and Supply 

Trends (Cordell et al. 1999). Projections were made nationally for 

four U.S. regions, with California included in the Pacific coast region. 

Trends for the Pacific region indicate wildlife viewing and nature 

study are expected to increase by 65 percent and double the number 

of days per year per person in the next 40 years. Fishing is expected 

to increase, while hunting is expected to decrease. 

The 2006 National Survey of Fishing, Hunting, 

and Wildlife-Associated Recreation – 

California (Survey) (USDOI et al. 2006) is a 

comprehensive publication that provides 

information about the numbers of U.S. 

anglers, hunters, and wildlife-watchers by 

state. The Survey found that 7.4 million 

California residents and nonresidents 16 years 

and older fished, hunted, or watched wildlife in 

California. Of the total participants, 1.7 million 

fished, 281 thousand hunted, and 6.3 million 

participated in wildlife-watching activities 

spending a total of $8.0 billion on wildlife 

recreation California. When compared to the 

1996 Survey (USDOI et al. 1996), the number 

of anglers decreased by 36 percent, number of 

hunters decreased by 45 percent, and wildlifewatching (away from home) increased by 23 

percent. 

American kestrel 

Photo by Steve Emmons 

114 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Locally, the Sacramento River Public Recreation Access Study 

(EDAW 2003) was conducted to assess existing and potential public 

recreation uses, accesses, needs, and opportunities along the 

Sacramento River between Red Bluff and Colusa. This study 

indicates a substantial public interest in recreational activities of 

boating, fishing, and hunting. Additionally, other uses such as bird 

watching, wildlife viewing, and other nature observation activities, 

are expected to increase 65 percent over the next 40 years. EDAW 

(2003) depicts a profile of the potential local refuge visitor as 

predominately Caucasian, 31-50 years of age with some college 

education/trade school education. As the population in the region 

grows, demand for recreation activities will increase. Planning will 

need to strike a balance between recreation use and conservation 

goals. 

8.3. Visitor Data 

The Complex utilizes a variety of methods for estimating the number 

of annual wildlife-dependent visits. The types of estimation methods 

used are direct observation, traffic counters, hunter permits, surveys, 

and estimation based on professional judgment. From these 

estimates, the numbers of visitors and visits are used to manage and 

improve the Refuges’ visitor services program. 

The National Wildlife Refuge System Visitation Estimation 

Workbook (USFWS 2005c) provides basic principles and definitions 

that have been used to describe the Refuge visitation estimation 

program. 

Refuge recreational or educational activities that are allowed and 

monitored include wildlife-dependent recreation (e.g. hunting, wildlife 

observation, photography, environmental education, and 

interpretation). Wildlife observation is more specifically reported as 

auto tour and hiking trail visits. 

A Refuge visitor (visitor) is a person that participates in at least one 

of the wildlife-dependent recreation activities. Visitors do not include 

staff, volunteers, researchers, contractors, special use permittees, or 

people who are traveling through the Refuges to reach another nonRefuge location. A single visitor may make several visits to the 

Refuges during the year by participating in one or more activities. 

A visitor is not the same as a Refuge visit (visit). A single visitor can 

make several visits to a Refuge on a single day by participating in 

several different activities. The total amount of visits on a given day is 

a count of only individuals. The amount of time for each individual 

visit is not accounted for; weather it be minutes to hours. 

It should be noted that there is not a 100 percent accurate method of 

counting all visitors or visits. Therefore, the numbers of visitors or 

visits reported are only estimates, although, the Refuges strive for 

Comprehensive Conservation Plan 115 
Chapter 3 

consistency and quality of estimation monitoring methods to improve 

the accuracy of the information collected. Unfortunately, the 

reporting systems such as the Refuge Management Information 

System (RMIS) and the Refuge Annual Performance Plan (RAPP) 

changed, making it more difficult to accurately compare annual 

visitation. 

Table 14 depicts the number of Refuge visitors and visits for some of 

the primary wildlife-dependent Refuge activities over the last five 

years. The environmental education, interpretation and photography 

blind visits were collected from reservation forms. Hunting visit 

information was collected from hunting permits and professional 

estimations of hunting activities (e.g. a hunter in the free roam area 

may hunt several species during waterfowl and pheasant season). The 

auto tour and hiking trail visits are a percentage of the vehicle counts 

that are recorded by a traffic counter at the Refuge entrance. The 

vehicle counts are multiplied by three based on a Refuge survey that 

identified an average of three people per vehicle. It should be noted 

that the 2002-2004 data is based on RMIS reports and 2005-2006 is 

based on RAPP. The data management systems are not directly 

comparable, since they each used a different reporting methodology 

to determine activity visits. The annual visitors are comparable, since 

the same formula was used. On Sacramento and Colusa Refuges, the 

formula is: Annual Visitors = Vehicle CountsX3 + Interpretation + 

EE + Hunting + Photo Blind Visitors. On Delevan and Sutter 

Refuges, the annual visitors equal the hunting visits. 

Western Fence Lizard 

Photo by Steve Emmons 

116 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

 

 

 

8.4. Recreation Fee Program 

The Service is one of four Federal land management agencies (Fish 

and Wildlife Service, Bureau of Land Management, National Park 

Service, and Forest Service), directed by Congress in 1996 to 

implement or expand fee collection sites as part of a program to 

explore the feasibility to better offset costs to administer recreation 

on public lands. 

The Refuge Environment 

Table 14. Refuge Visitation Trends FY 2002-2006 

Five 

2002 2003 2004 2005 2006 Year 

Average 

Sacramento 

Annual Visitors 67,619 75,528 71,617 89,138 86,165 78,103 

Auto Tour Visits 48,345 53,842 51,646 73,149 60,616 57,520 

Hiking Trail Visits 8,566 8,418 8,064 9,443 8,735 8,645 

Hunting Visits 8,203 7,052 6,851 7,386 7,683 7,435 

Environmental 

Education Visits 2,851 3,027 2,799 3,032 2,528 2,847 

Interpretation 

Visits 807 1,065 630 125 150 555 

Photo Blind Visits 20 33 39 34 33 32 

Delevan 

Annual Visitors 6,073 5,660 5,881 5,678 6,386 5,936 

Hunting Visits 6,073 5,660 5,881 5,678 6,386 5,936 

Colusa 

Annual Visitors 24,308 31,135 26,364 20,426 16,284 25,311 

Auto Tour Visits 16,246 21,847 18,084 16,547 13,027 17,150 

Hiking Trail Visits 4,185 5,610 4,496 4,127 3,256 4,335 

Hunting Visits 3,877 3,678 3,784 3,879 3,910 3,826 

Environmental 

Education Visits 168 60 65 39 24 71 

Interpretation 

Visits 0 0 88 0 0 18 

Photo Blind Visits NA NA NA NA 12 12 

Sutter 

Annual Visitors 3,058 1,241 2,620 2,870 2,152 2,388 

Hunting Visits 3,058 1,241 2,620 2,870 2,152 2,388 

TOTAL ANNUAL 

VISITORS 96,924 108,135 101,869 118,112 110,999 107,208 

Comprehensive Conservation Plan 117 
Chapter 3 

The fee demonstration program was a four year effort to create 

innovative approaches and methods to charge and collect fees for 

recreation services provided on Service lands. An entrance fee 

program was implemented at Sacramento Refuge during the spring 

of 1998. This involved constructing a parking area, sidewalk, kiosk 

with interpretive panels, and automated fee machine. 

A survey was completed in 1998 to determine compliance and the 

number of people per vehicle. The survey revealed that there was a 

90 percent compliance of visitors that paid before entering the 

Refuge. 

In 2004, Congress passed the Federal Lands Recreation 

Enhancement Act which allows the government to charge a fee for 

recreation use of public lands managed by the Service, Bureau of 

Reclamation, National Park Service, Bureau of Land Management, 

and Forest Service. 

Currently, there is an entrance fee program for Sacramento Refuge. 

A fee for vehicles is collected to pay for visitor facilities and wildlife 

habitat improvements. A $3 day pass, $12 Refuge Annual Pass or $20 

commercial pass can be purchased on-site. Holders of a Federal Duck 

Stamp or Golden Eagle, Age, Access Passport, or America the 

Beautiful Pass enter for free. The entrance fee is waived for 

educational groups studying nature as part of a course of curriculum. 

Visitors pay the entrance fee at an automated fee machine at the 

entrance to the Refuge. 

The entrance fee generates approximately $13,000 annually, which is 

used to hire two visitor services assistants for October-March. The 

assistants help with many daily tasks, staff the visitor center on the 

weekends, facilitate the school groups, update the website, provide 

hunt data, and answer the phone. 

There is also a photography blind fee of $10 per reservation. See the 

Wildlife Observation section (Section 8.7) for details. 

8.5. Hunting 

The hunting program is administered by the Service in cooperation 

with the CDFG. The Service manages the Refuges’ land, habitat and 

facilities; the CDFG selects and processes the Refuge hunters. 

Hunting is permitted on portions of Sacramento, Delevan, Colusa, 

and Sutter Refuges. Hunting of waterfowl, coots, common moorhens, 

snipe, and pheasants is permitted on Saturdays, Sundays, and 

Wednesdays during hunting seasons established by the California 

Fish and Game Commission. 

118 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Waterfowl hunter 

Photo by Mike Carpenter 

The Refuges have spaced blinds, spaced hunt sites (islands), assigned 

ponds, and free roam areas. Pheasants may only be hunted in the free 

roam areas, except for the Special Monday Pheasant Hunt, which is 

held the first Monday of the regular season. On this day, the entire 

hunt areas at Sacramento, Delevan, and Colusa Refuges are opened 

to pheasant hunting, including the spaced blind and assigned pond 

areas. 

Harvest success, as measured by the number of birds per hunter per 

day (average), has remained comparatively consistent since the 

Refuge hunting programs were established. This consistency has 

occurred despite some rather significant changes in regulations, total 

birds harvested on the Complex, and trends on individual Refuges. 

For the four Refuges, the average number of birds per hunter in 

recent years is approximately 2.25 to 2.50, plus or minus 0.5 

depending on the Refuge or year. All individual Refuge averages are 

typically equal to or greater than the annual average for all “Type A” 

public hunt areas in California. For example, for the 2006/07 

waterfowl season, Colusa (2.97), Delevan (3.3), Sacramento (2.65) and 

Sutter (2.46) Refuges all exceeded the statewide season average of 

2.37 birds per hunter. Hunter success does vary by day, with weather 

conditions being the primary reason for the differences. However, all 

other factors being equal, the second consecutive day (Sunday) of 

hunting usually results in a lower average than the preceding hunt 

day (Saturday) or the middle of the week (Wednesday). 

Harvest data indicate that ducks make up 95 percent of the hunter 

bag. The top six species of ducks harvested are mallard (22.3 

percent), gadwall (18.5 percent), green-winged teal (14.5 percent), 

northern shoveler (13.5 percent), American wigeon (12.6 percent), 

and northern pintail (7.5 percent) (Table 15). Geese harvested include 

snow (53.8 percent), white-fronted (30.2 percent), and Ross’s (13.4 

percent) (Table 16). The majority of the goose harvest occurs on 

Sacramento and Delevan Refuges. 

Comprehensive Conservation Plan 119 
Chapter 3 

Table 15. Primary Duck Species Harvested on the Sacramento Complex 

(2004-2006 Season). 

Mallard Gadwall GWTeal Shoveler Wigeon Pintail 

Sacramento 

2006-07 2,992 3,324 2,029 3,294 2,015 1,688 

2005-06 3,053 2,184 2,094 2,340 1,770 1,519 

2004-05 3,392 2,237 1,995 1,794 1,373 1,112 

Average 3,146 2,582 2,039 2,476 1,719 1,440 

Delevan 

2006-07 2,991 4,332 2,518 3,959 2,304 1,553 

2005-06 4,037 3,001 2,504 2,200 2,257 1,412 

2004-05 3,319 2,854 2,117 1,776 1,808 655 

Average 3,449 3,396 2,380 2,645 2,123 1,207 

Colusa 

2006-07 1,287 2,774 1,770 1,468 868 720 

2005-06 2,912 1,736 1,538 716 814 678 

2004-05 2,625 2,067 1,639 734 1,248 381 

Average 2,275 2,192 1,649 973 977 593 

Sutter 

2006-07 2,182 564 1,138 792 1,481 665 

2005-06 1,558 227 587 176 613 263 

2004-05 1,875 1,469 1,026 299 1,469 249 

Average 1,872 753 917 422 1,188 392 

Average 

Total 10,742 8,923 6,985 6,516 6,077 3,632 

Percent of 

Grand Total1 22.3 18.5 14.5 13.5 12.6 7.5 

1

 The Grand Total includes other duck species that were harvested (48,233=Grand 

Total). 

Waterfowl hunting 

USFWS photo 

120 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Table 16. Primary Goose Species Harvested on the Sacramento 

Complex (2004-2006 Season). 

Snow Ross’s White-front 

Sacramento 

2006-07 1,614 295 652 

2005-06 985 220 317 

2004-05 835 196 285 

Average 1,145 237 418 

Delevan 

2006-07 1,344 229 736 

2005-06 1,061 204 364 

2004-05 461 176 354 

Average 955 203 485 

Colusa 

2006-07 435 221 88 

2005-06 227 84 45 

2004-05 149 90 84 

Average 270 132 72 

Sutter 

2006-07 204 90 834 

2005-06 73 14 203 

2004-05 44 37 208 

Average 107 47 415 

Average Total 2,477 619 1,390 

Percent of Grand 

Total1 53.8 13.4 30.2 

1

 The Grand Total includes other goose species that were harvested 

(4,599=Grand Total). 

Snow goose 

Photo by Steve Emmons 

Comprehensive Conservation Plan 121 
Sacramento Refuge check station (1964) 

USFWS Photo 

Chapter 3 

8.5.1. Sacramento Refuge Hunting History 

In 1963, the Sacramento Refuge was opened to public hunting of 

waterfowl. The program was initiated by the Service in conjunction 

with CDFG, whose staff members presently operate the program. 

Approximately 3,585 acres of the southern portion of the Refuge was 

opened to a maximum of 250 adult hunters. The initial fee was $2.50 

per hunter per day. Hunters were largely dependent on a first come, 

first served system and a mail-in reservation system for obtaining a 

permit to hunt. The number of hunters on any given day remains 

about twice the actual capacity of the hunting area. Hunters leaving 

the area are usually quickly replaced by others waiting to hunt. 

In 1978, the spaced blind program was initiated in order to improve 

the quality of the hunt and to meet national and regional policies. 

This involved the elimination of firing lines, overcrowding, and 

extreme competition among hunters. The blinds were either inground metal pits or above-ground platforms that could 

accommodate up to four hunters. The blinds were well spaced to 

improve safety and hunting quality. In the early years, hunters were 

assigned a blind, but more recently have been allowed to select their 

blinds in order of their reservation or sweat line numbers. They were 

required to hunt from within their assigned blinds until 1991, when 

the regulation was relaxed to include the area within 100 feet of the 

blind. During 1997 to 2003, concrete pit blinds were installed to 

replace all the metal pit and platform blinds. Safari Club 

International contributed the first two blinds, Blinds 9 and 13. 

In 1991, the Refuge eliminated the requirement that non-reservation 

hunters remain in the check station parking lot after receiving their 

sweat line number. In addition, an on-site lottery draw system for 

non-reservation numbers was implemented to reduce overnight 

camping and provide a more equitable system of hunter access. A 

new check station building was constructed in 1999, and an 

122 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

The Refuge Environment 

information kiosk was installed near the check station in 2004. The 

first assigned pond, replacing Blind 55, was established in 2006. 

A Special Monday Pheasant Hunt was added to the hunt program in 

1981. In addition, in 1991 an annual one-day Junior Waterfowl Hunt 

in the spaced blind area began. The first Youth Waterfowl Hunt was 

hosted on the Saturday before the opening of waterfowl hunting 

season in October 1996. Thereafter, Youth Hunts were hosted during 

the weekend after the end of the waterfowl hunting season. 

In 1997, as the result of an accessibility evaluation, two additional 

disabled blinds, Blinds 23D and 27D, were constructed. 

8.5.2. Sacramento Current Hunting Conditions 

Hunting of waterfowl, coot, common moorhen, snipe, and pheasant is 

restricted to 3,566 acres south of Road 68 on Sacramento Refuge on 

Wednesdays, Saturdays, and Sundays during the legal seasons (Table 

17). 

Table 17. Sacramento Refuge Hunting Conditions. 

Spaced 

Blind 

Area 

Assigned 

Pond Area 

(# parties) 

Free 

Roam 

Area 

Pheasant 

Only 

Acres dry 241 27 336 127 

Acres flooded 1606 55 1,174 

Total acres 1847 82 1,510 

Number of blinds 45 

Number of 

assigned ponds 

1 

Maximum adult 

hunter quota 

180 4 (1) 75 

Wetland 

acres/hunter or 

hunt site 

35.7 55 15.6 

Sacramento Refuge has spaced blind, assigned pond, and free roam 

areas that consists of managed wetland, grassland, vernal pool, and 

alkali meadow habitats. Blinds are in-ground, concrete pits spaced 

250 to 400 yards apart. Hunters must remain within 100 feet of their 

assigned blind. Free roam and assigned pond hunters move 

unrestricted within the signed hunting area boundary. Directional 

signs guide hunters to their respective hunting areas, while additional 

reflective stakes direct hunters to their specific blind site. The 

hunting areas are accessible only by foot from four parking areas. 

Pheasant and snipe may be hunted on waterfowl hunt days in the free 

roam and pheasant only areas. Pheasant may also be hunted on the 

Comprehensive Conservation Plan 123 
Chapter 3 

first Monday of the season in free roam, spaced blind, and assigned 

pond areas. 

Hunter quotas are based on acres of available wetland habitat and 

are adjusted depending upon water conditions. Fully flooded 

conditions provide up to 45 blinds (up to four people per blind), one 

assigned pond (up to four people) and up to 75 hunters in the free 

roam area. In addition to quotas, habitat management, pond size, 

daily weather conditions, and waterfowl flight patterns influence 

hunter distribution. 

Sacramento Refuge has three blind sites (Blinds 5D, 23D, and 27D) 

designated for hunters with disabilities. These sites may be accessed 

by motor vehicle or an all-terrain-vehicle from the parking areas. 

Additionally, there is a parking area to access Blinds 23D and 27D, 

and a designated boat launch in the free roam area of Tract 38 for 

hunters with disabilities. During the 2006/2007 season, there were 212 

visits by 62 individual hunters with disabilities. 

Waterfowl hunting from disabled hunting blind 

USFWS photo 

8.5.3. Delevan Refuge Hunting History 

The hunt program at Delevan Refuge began in 1963 with the opening 

of 2,000 acres to free roam hunting. In 1989, a portion of the free 

roam area was converted to accommodate 26 spaced hunting sites or 

islands. These sites could accommodate up to four hunters and were 

well spaced to improve safety and hunting quality. Hunters selecting 

such sites were required to remain within 100 feet of a marker stake 

designating the assigned hunting site and were limited to waterfowl 

hunting only. Pheasant and snipe were harvested in the free roam 

areas only. The Delevan check station was moved from off of Maxwell 

Road to Tract 27 off of Four Mile Road in the 1980s. A new check 

station was constructed in 1997 and a hunter kiosk was installed in 

2003. In 2004, assigned ponds were established on Delevan Refuge. 

Ponds 11 and 12A were the first to become assigned ponds, followed 

by Pond 17 in 2005. 

124 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

In 1994, a blind was constructed in Tract 27.2 in a small pond close to 

the check station and was opened to disabled hunters only. In 1997, 

Blind 13D was added as an additional disabled site and the original 

disabled blind was renamed as Blind 29D. Able-bodied hunters were 

allowed to refill both blinds after 3:00 p.m. 

In 1998, the Disabled Access Working Group (DAWG) requested the 

Service construct Blind 30D. The Refuge was concerned that if both 

Blinds 30D and 29D were filled with four hunters, a firing line might 

result. In 2001, the CDFG check station manager reported that Blind 

30D was cutting off the natural flyway from the north closed area into 

the free roam area south of Blind 30D. Since that time, the Complex, 

Refuge Hunting Program Working Group, and DAWG have studied 

various proposals to locate an alternate site for Blind 30D. A flyer 

was distributed at the check stations, but no suggestions were 

received. The Service is now considering leaving Blind 30D at the 

present location. Since Blinds 29D and 30D are located in small 

ponds, there is no refill by able-bodied hunters after 3:00 pm. 

In 2004, the Refuge introduced a floating pontoon blind in the free 

roam area for mobility-impaired hunters. The pontoon boat was 

purchased with a grant from Safari Club International. 

The first Special Monday Pheasant 

Hunt was started in 1989. In 1991, 

the Refuge eliminated the sweat 

line system altogether and 

implemented an on-site lottery 

draw system for non-reservation 

hunters. In 1992, an annual oneday Junior Waterfowl Hunt in the 

spaced blind area began. The first 

Youth Waterfowl Hunt was hosted 

on the Saturday before the opening 

of waterfowl hunting season in 

October 1996. Thereafter, Youth 

Hunts were hosted during the 

weekend after the end of the 

waterfowl hunting season. 

Junior waterfowl hunter 

USFWS photo 

Comprehensive Conservation Plan 125 
Chapter 3 

8.5.4. Delevan Current Hunting Conditions 

Hunting of waterfowl, coot, common moorhen, snipe, and pheasant is 

restricted to 1,922 acres on the south half of Delevan Refuge on 

Wednesdays, Saturdays, and Sundays during the legal seasons (Table 

18). 

Table 18. Delevan Refuge Hunting Conditions. 

Spaced 

Hunt Area 

Assigned 

Pond Area 

(# parties) 

Free 

Roam 

Area 

Acres dry 22 0 192 

Acres flooded 746 129 *833 

Total acres 768 129 1,025 

Total blinds 26 

Total Assigned Ponds 3 

Maximum adult hunter 

quota 

104 12 (3) **58 

Wetland acres/hunter 

or hunt site 

28.7 43.0 14.4 

* Does not include acres for T41.2 when it gets flooded December - 

January 

**Increased to 62 during December-January when T41.2 is flooded 

Delevan Refuge has spaced hunt sites, assigned ponds, and a free 

roam area that consists of managed wetland, grassland, vernal pool, 

and alkali meadow habitats. Hunt sites consist of a dirt island 

(approximately 10 feet x 20 feet) surrounded by cattail or bulrush. 

Hunters must remain within 100 feet of their assigned hunt site. Free 

roam and assigned pond hunters move unrestricted within the signed 

hunting area boundary. Directional signs guide hunters to their 

respective hunting areas, while additional reflective stakes direct 

hunters to their assigned hunt site. The hunting areas are accessible 

only by foot from three parking areas. 

Pheasant and snipe may be hunted on waterfowl hunt days in the free 

roam areas. Pheasant may also be hunted on the first Monday of the 

season in free roam, spaced hunt sites, and assigned pond areas. 

Hunter quotas are based on acres of available wetland habitat and 

are adjusted depending upon water conditions. Fully flooded 

conditions provide up to 26 hunt sites (up to four people per hunt 

site), three assigned ponds (up to four people per pond) and up to 58 

free roam hunters. In addition to quotas, habitat management, pond 

size, daily weather conditions, and waterfowl flight patterns influence 

hunter distribution. 

Delevan Refuge has three spaced hunt sites (Blinds 13D, 29D, and 

30D) designated for hunters with disabilities. These sites may be 

126 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

accessed by motor vehicle or an all-terrain-vehicle from the parking 

areas. A floating pontoon blind is located in Tract 34.3 as a free roam 

hunting opportunity. In addition, there are designated disabled 

accessible boat launches in the free roam area of Tracts 33 and 34.3. 

In the 2006/2007 season, there were 223 visits by 53 individual 

hunters with disabilities. 

8.5.5. Colusa Refuge Hunting History 

Colusa Refuge was opened to free roam hunting in 1950. The hunting 

area acres have ranged from 1,100 in the 1960s to 1,921 acres today. 

The lottery draw was implemented in 1998. Also in 1998, a boat ramp 

and disabled parking area were constructed. A new hunter check 

station was constructed in a more southern location (Tract 23) in 

1999, and an information kiosk was installed in 2004. In 2004, eight 

assigned ponds were established and, in 2005, the first blind for 

disabled hunters was constructed in the northeast corner of Pool 2. 

Colusa Refuge check station (1953) 

USFWS Photo 

8.5.6. Colusa Current Hunting Conditions 

Hunting of waterfowl, coot, common moorhen, snipe, and pheasant is 

restricted to 1,921 acres south of Able Road on Colusa Refuge on 

Wednesdays, Saturdays, and Sundays during the legal seasons (Table 

19). 

Comprehensive Conservation Plan 127 
Chapter 3 

Table 19. Colusa Refuge Hunting Conditions. 

Assigned 

Pond Area 

(# parties) 

Free 

Roam 

Area 

West 

Free 

Roam 

Area 

East 

Pheasant 

Only 

Area 

Acres dry 0 488 67 60 

Acres flooded 339 429 538 

Total acres 339 917 605 

Total assigned 

ponds 

8 

Maximum adult 

hunter quota 

26 (13) 14 40 

Wetland 

acres/hunter or 

hunt site 

26.1 30.6 13.4 

Colusa Refuge has assigned pond and free roam areas that primarily 

consists of managed wetland, grassland, vernal pool, and alkali 

meadow habitats. Free roam and assigned pond hunters move 

unrestricted within the signed hunting area boundary. Directional 

signs guide hunters to their respective hunting areas. The hunting 

areas are accessible only by foot from three parking areas. In 

addition, hunters with disabilities may access Pool 2 from the 

disabled parking area via a boat ramp or access a blind in the 

northeast corner. 

Pheasant and snipe may be hunted on waterfowl hunt days in the free 

roam and pheasant only areas. Pheasant may also be hunted on the 

first Monday of the season in free roam and assigned pond areas. 

Hunter quotas are based on acres of available wetland 

habitat and are adjusted depending upon water 

conditions. Fully flooded conditions provide up to 

eight assigned ponds (two adult hunters per party) 

and up to 54 free roam hunters. Ponds 4, 5 and 7-10 

allow one party per pond, Pool 1 allows up to four 

parties per pond. Pool 2 allows up to three parties 

including two disabled parties and one party which 

must have a junior hunter. In the 2006/2007 season, 

Pool 2 had 236 hunter visits and the hunters that 

reported using the blind on 10 days resulted in 22 

hunter visits. In addition to quotas, habitat 

management, pond size, daily weather conditions, and 

waterfowl flight patterns influence hunter 

distribution. 

Greater white-fronted geese 

Photo by Steve Emmons 

128 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

8.5.7. Sutter Refuge Hunting History 

The hunt program began on Sutter Refuge in 1953 when 1,350 acres 

were opened to free roam hunting. Since that time, the annual hunt 

program has varied from a complete closure in 1978, to a maximum of 

1,441 acres in 1987. The Refuge is located in the Sutter Bypass and 

consequently has suffered from flooding and resultant temporary 

closures of the hunt program more frequently than any other Refuge 

on the Complex. A boat access ramp in Tract 17 for disabled hunters 

was constructed in 1998. 

Sutter Refuge check station (1956) 

USFWS Photo 

8.5.8. Sutter Current Hunting Conditions 

Hunting of waterfowl, coot, common moorhen, snipe, and pheasant is 

restricted to 1,116 acres on the south half of Sutter Refuge on 

Wednesdays, Saturdays, and Sundays during the legal seasons (Table 

20). 

Table 20. Sutter Refuge Hunting Conditions. 

Free Roam 

Area 

Pheasant 

Only Area 

Acres dry 0 125 

Acres flooded 987 4 

Total acres 987 129 

Maximum hunter quota 70 

Wetland acres/hunter 14.1 

Sutter Refuge is entirely a free roam area that primarily consists of 

managed wetland and grassland habitats. Hunters move unrestricted 

within the signed hunting area boundary. The hunting areas are 

accessible only by foot from two parking areas. In addition, there is a 

designated boat launch with a parking area available to hunters with 

disabilities, in the southeast corner of Tract 17. There are minimal 

Comprehensive Conservation Plan 129 
Chapter 3 

disabled hunter visits on Sutter Refuge. Pheasant and snipe can be 

hunted in the free roam and pheasant only areas on the Refuge on 

waterfowl hunt days. 

Hunter quotas are based on acres of available wetland habitat and 

are adjusted depending upon water conditions. Fully flooded 

conditions provide up to 70 free roam hunters. In addition to quotas, 

habitat management, pond size, daily weather conditions, and 

waterfowl flight patterns influence hunter distribution. 

8.5.9. Hunter Working Groups 

The Refuge Hunting Program Working Group was established in 

1991 to exchange ideas and information regarding the Complex 

hunting program. The Disabled Access Working Group was 

established in 1999 to discuss disabled hunting access issues on the 

Complex. In 2006, the groups were combined to form the Sacramento 

Refuge Complex Hunting Program Working Group. 

8.6. Fishing 

Currently there is no public fishing access on Sacramento, Delevan, 

Colusa, and Sutter Refuges. 

Fishing once occurred on all four of the Refuges. The angler visits 

were estimated by periodic surveys. The most common fish caught 

were channel catfish, yellow bullhead, bluegill, perch, sunfish, carp, 

and largemouth bass. 

Sacramento Refuge fishing access was open 1964 to 1991 during 

February 15 to October 1 along Logan Creek for one mile south of 

Road 68. Visitation was estimated through periodic surveys at just 

over 500 visits annually. Anglers were reported to catch primarily 

catfish and largemouth bass. The most popular place to fish was not 

on Refuge property. Visitors would park on County Road 68 and fish 

near the bridge. There was reoccurring problems with litter and 

trespass north into the closed area, which disturbed wildlife including 

nesting birds. Subsequently, the area was closed to fishing in 1991. 

Almost two miles of fishing access was open along the Delevan 

Refuge’s Colusa Basin Drain. The area was open 1964 to 1993 during 

February 15 –October 1. Angler visits over a 1990 to 1993 varied from 

approximately 940 to 2,880 annually, with catfish and largemouth 

bass the primary fish caught. Unfortunately, vandalism of Refuge 

gates and signs, trespass on Refuge land and adjacent private 

properties, illegal campfires, and destruction of Federal property 

occurred repeatedly. Following written and verbal complaints from 

the Maxwell Irrigation District, law enforcement was increased to 

educate anglers about Refuge regulations. In spite of these increased 

efforts, vandalism continued throughout the year. Because water 

quality was questionable, relatively few regular anglers utilized the 

area and the fishing area was closed in 1994. 

130 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Colusa Refuge was open to fishing from 1963 to 1989 along a 11⁄4 mile 

stretch of the Colusa Basin Drain. Since the fishing area was not 

located on Refuge property, the fishing signs were removed in 1989. 

Anglers fished in the Sutter Bypass, but the official date of opening 

Sutter Refuge to fishing to the public was never documented. In 1962, 

it was noted that anglers along the boundaries of the Refuge were a 

nuisance, stating that they would burn or destroy signs, litter, and 

trespass. In 1963, it was recorded that anglers were attracted to the 

area, reaching up to 50 vehicles per day and they also caught up to 8 

pound catfish. As on the other Refuges, due to the repeated 

violations, refuge management closed the area to fishing. 

8.7. Wildlife Observation 

Numerous wildlife observation opportunities are available on the 

Refuges. On Sacramento Refuge, the six-mile auto tour route and 

two-mile walking trail (Wetlands Walk Trail) meander along marshes 

and riparian areas. There are two park and stretch areas on the auto 

tour route where visitors are encouraged to get out of their vehicles 

to view wildlife. At the first park-and-stretch area halfway along the 

auto tour route, there is a three-tier wildlife viewing platform with 

two spotting scopes. The auto tour route and trail are open sunrise to 

sunset year-round. 

Wildlife viewing platform at Sacramento Refuge

USFWS photo 

On Colusa Refuge, visitors enjoy wildlife viewing and photography as 

they drive the three-mile, graveled auto tour route adjacent to 

managed wetlands. A universally accessible wildlife viewing platform 

is located at the beginning of the auto tour route. A one-mile walking 

trail (Discovery Walk Trail) is located along a lush riparian slough. 

The auto tour route and trail are open sunrise to sunset year-round. 

Comprehensive Conservation Plan 131 
Photo by Mike Peters 

Chapter 3 

Wildlife viewing platform at Colusa Refuge 

Wildlife observation on Delevan and Sutter Refuges is limited to 

adjacent county roads. Delevan Refuge also has an undeveloped 

Watchable Wildlife site on Maxwell Road, adjacent to the Refuge’s 

southern boundary. 

8.8. Wildlife Photography 

The auto tour routes and walking trails on Sacramento Refuge and 

Colusa Refuge provide excellent photographic opportunities. The 

best time of year for photography occurs from November through 

February, when a variety of waterfowl and shorebirds are present. 

View from Photo Blind 1 

Photo by Mike Peters 

Additionally, there are two photography blinds on Sacramento 

Refuge and one on Colusa Refuge. The blinds may be reserved one 

day each week only on Wednesdays through Sundays for a small fee 

($10). They are also available October through March depending on 

habitat conditions. Photographers may request up to three 

reservations each season and may be placed on a waiting list if the 

blind or day requested is filled. Photographers also complete an 

132 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Photo Blind 2 at Sacramento Refuge 

Photo by Steve Emmons 

The Refuge Environment 

evaluation that reports photographed species, time spent, and 

comments. 

Photographers must be in the blind at least one-half hour before 

sunrise. They must park in the designated parking area and proceed 

directly to the assigned blind on foot. Stakes with reflective tape 

mark the route from the parking area to the blind. The route is 

designed to minimize disturbance; therefore, deviation from the 

staked route is not allowed. Photographers may leave the blind at any 

time, but once the blind has been vacated, returning to the blind is 

not permitted. 

The blinds are approximately 300 yards within the wetlands. They 

are 42' x 6' wide and 5' high. They have adjustable camera size 

openings in three sides. The blinds accommodate one person 

comfortably; however, two people at a time are allowed. Tree snags 

and islands have been placed to encourage birds to perch or rest 

about 40 feet from each blind. 

8.9. Environmental Education 

Environmental education is comprised of teacher or leader-conducted 

activities that are intended to actively involve students or others in 

hands-on activities. These activities are designed to promote 

discovery and fact-finding, develop problem-solving skills, and lead to 

personal involvement and action. The Service focuses on 

kindergarten through twelfth grade students. 

The Environmental Education Guide for the Complex describes the 

activities, facilities, and resources available on the Refuges. The 

environmental education program was restructured in 2005 to 

increase the involvement of teachers or leaders in conducting their 

pre-selected activities. The program offers several ways for the 

classes to experience the Complex. Specifically, at the Sacramento 

Refuge they are welcomed by visitor services staff and have access to 

the diorama, Discovery Room, and Refuge videos. For the remainder 

of their visit, the teachers or leaders guide their group through their 

pre-planned tour using the two-mile walking trail, kiosk area and sixComprehensive Conservation Plan 133 
Chapter 3 

mile auto tour. On Colusa Refuge, students utilize the new visitor 

facilities including restrooms, welcome kiosk, viewing platform. 

Although the Refuges are open to the public from sunrise to sunset 

daily, we encourage groups to make reservations two weeks in 

advance to ensure that they will have the best possible experience 

and that needed resource materials are available. They may call, fax 

or visit our website to make reservations. 

8.9.1. Wetlands Walk 

On Sacramento Refuge, visitors using the Wetlands Walk Guide may 

meander through the fourteen stops on the two-mile trail for an hour 

long adventure or if time is limited, walk only halfway after 

experiencing an abundance of unique viewing opportunities. 

8.9.2. Discovery Packs and Teacher Resources 

For an even more comprehensive environmental education 

experience, there is a fully equipped backpack, or Discovery Pack, to 

teach as many as five activities along the Wetlands Walk. The pack 

contains dip nets, field guides, plant mounts, bug boxes, lenses, and 

written materials. A teacher’s guide can be sent, upon request, prior 

to the visit. 

Binoculars and waterfowl guides are also available on loan from the 

Refuge Headquarters. The Environmental Education Guide and the 

Complex website list many other resources available. 

8.9.3. Auto Tour with Radio Station

Visitors may tune into Sacramento Refuge’s radio station (93.1 FM)

to learn about the diversity of plants and animals as they drive the 

auto tour. 

Sacramento Refuge auto tour route 

Photo by Steve Emmons 

134 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

8.9.4. Junior Duck Stamp Program 

Sacramento Refuge coordinates the Federal Junior Duck Stamp 

Conservation and Design Program for California. As the State 

coordinator, refuge staff manages the art contest, outreach, and art 

tour of the winning youth art entries. Students in kindergarten 

through high school are involved in this innovative, curriculum-based 

program through an annual art competition in each state. Further 

information about the Federal Duck Stamp Program and Federal 

Junior Duck Stamp Art Contest may be found on the website: 

www.fws.gov/duckstamps. 

8.10. Interpretation and Outreach 

Interpretation involves participants of all ages who learn about the 

complex issues confronting fish and wildlife resource management as 

they voluntarily engage in stimulating and enjoyable activities. Firsthand experience with the environment is emphasized although 

presentations, audiovisual media, and exhibits are often necessary 

components of the interpretive program. The Service’s Children and 

Nature initiative (USFWS 2008) strives to ensure that America’s 

children have enjoyable and meaningful experiences in the out-ofdoors and develop strong life-long connections with the natural world. 

The Refuges also strive to meet this initiative. 

Refuge brochures providing information on the Complex, Watchable 

Wildlife, and hunting have been developed and revised over the 

years. The Wetlands Walk Guide and the Sacramento Valley Birding 

Trail Guide and Map were completed in 2006. A variety of videos are 

also available for viewing upon request. The Sacramento Valley 

Refuge: An Unfinished Symphony and America’s National Wildlife 

Refuge System: Where Wildlife Comes First, are the most popular 

videos. The Unfinished Symphony was written and filmed on location 

in 2003 as part of the Refuge System Centennial Celebration. 

A bookstore in the Sacramento Refuge Visitor Center (Headquarters 

Office) was created in 1990 via cooperative agreement with the San 

Francisco Bay Wildlife Society. The cooperative agreement was 

terminated with San Francisco Bay Wildlife Society in 2001 and a 

new cooperative agreement was signed with Altacal Audubon Society 

of Chico, CA in 2002. 

Refuge-related information is provided at annual local festivals or 

during special events, such as the California State Fair, International 

Migratory Bird Day, Snow Goose Festival, National Wildlife Refuge 

Week, Pacific Flyway Decoy Association, Coleman National Fish 

Hatchery Salmon Festival, Chico Endangered Species Fair, 

California Waterfowl Association (CWA) Art Camp, and CWA Marsh 

Madness. During 2005, approximately 13,000 individuals attended the 

presentations and saw exhibits at these events. 

Comprehensive Conservation Plan 135 
8.10.1. Website

Refuge staff maintains a website for the Complex: 

http://sacramentovalleyrefuges.fws.gov. Events, wildlife survey data, 

hunting data, planning documents, and information about the 

Refuges are posted on this website.

8.11. Non-wildlife dependent Recreation 

The only non-wildlife dependent recreation permitted on the Refuges 

is bicycling on the auto tour route on Sacramento Refuge. Bicycling 

can facilitate non-consumptive priority public uses, including wildlife 

observation, photography, environmental education, and 

interpretation. 

8.12. Youth Program 

A Youth Conservation Corps (YCC) program, the first in over two 

decades, was implemented during the summer of 2005. It consisted of 

one crew leader and four crew members and, in 2006, expanded to 

include one youth leader. During the eight-week program, enrollees 

complete maintenance, fence construction, and painting projects. 

YCC contributes over 1,000 work project hours annually. For every 

eight hours of work, one hour of environmental education is provided 

as field trips, presentations, or discussions. 

Chapter 3 

YCC crew installing burrowing owl nesting box 

USFWS photo 

136 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

8.13. Volunteer Program 

The National Wildlife Refuge System Volunteer and Partnership 

Enhancement Act of 1998 (P.L. 105-242) strengthens the Refuge 

System’s role in developing relationships with volunteers. Volunteers 

possess knowledge, skills, and abilities that can enhance the scope of 

Refuge operations. Volunteers enrich refuge staff with their gift of 

time, skills, and energy. Refuge staff will initiate, support, and 

nurture relationships with volunteers so that they may continue to be 

an integral part of Refuge programs and management. The volunteer 

program is managed in accordance with the Fish and Wildlife Service 

Manual, Part 150, Chapters 1-3, “Volunteer Services Program”, and 

Part 240 Chapter 9 “Occupational Safety and Health, Volunteer and 

Youth Program”. 

Currently the volunteer program consists of 69 individuals that assist 

with biological, environmental education, interpretation, wildlife 

observation, hunting, and maintenance events and activities. 

Additional individuals are signed up for one-time events such as 

Brush Up Day of the hunting areas and trail maintenance by Altacal 

Audubon Society. The Refuges also support and participate in annual 

Eagle Scout projects. 

9. Cooperation with Adjacent Landowners 

The Refuges are part of a mosaic of public and private land in the 

Sacramento Valley. Private lands are mostly agricultural land (rice, 

orchards, row crops), with some private duck-hunting clubs, 

farmsteads, businesses, trailer parks, and isolated homes. To 

maximize our conservation efforts the Complex encourages and 

supports the cooperative approach to problem solving by working 

with neighbors on common issues (e.g. trespass, fire and fuel break 

management, drainage, etc.). The refuge manager is the primary 

contact for the cooperation with adjacent landowners. 

10. Fire Prevention and Hazard Reduction 

Fire prevention and fire hazard reduction programs are intended to 

protect and reduce risks to human life and property at nearby homes, 

farms, businesses, developed areas, structures, improvements, and 

the Refuge boundaries. The Wildland Urban Interface (WUI) 

program is part of the National Fire Plan and is designed to reduce 

the potential for wildfire damage in zones where wildlands and 

infrastructure (assets at-risk) mix. The WUI program emphasizes 

pre-fire management around communities that are listed as “at-risk” 

to wildfire in the Federal Register and by the state of California. 

The program is part of a national stimulus package to implement 

wildfire hazard reduction projects on Federal lands, especially 

emphasizing use of local contractors. Development of site-specific 

projects includes collaboration with local landowners, local, county 

and State firefighting departments, the refuge manager, biologists, 

and fire management officer. Projects include, but are not limited to 

Comprehensive Conservation Plan 137 
Chapter 3 

prescribed burns for fuel reduction, permanent fuel breaks, selective 

cutting, grazing, mowing, or disking along boundaries and developed 

areas, and cooperative agreements with local fire districts for wildfire 

suppression. 

The Refuges have a fire management program of ten employees (six 

permanent and four seasonals) and three engines. A regional 

Wildland Urban Interface Specialist is also stationed at Sacramento 

Refuge and assists with development and implementation of fire 

protection programs throughout the Complex. 

The Complex has averaged nine prescribed fires per year over the 

last ten years, averaging about 560 acres burned per year. Objectives 

for all of these burns include hazard reduction. Additional objectives 

have also included threatened and endangered species management, 

invasive plant reduction, habitat maintenance, and disease 

prevention. 

The Complex has averaged four wildfires per year over the last ten 

years, burning an average of about 113 acres per year. Many of these 

fires have started off-Refuge. Refuge fire crews have also responded 

to wildfires adjacent to Refuge property under local, county, and 

statewide wildfire mutual aid agreements. All wildfires have been 

human-caused, including escaped fires from the burning of fields, 

ditches, or natural vegetation (17 fires of 50 recorded in 15 years). 

Other causes have included trains, mowers and agricultural 

equipment, electrical lines/equipment, smoking, and 

intentional/suspicious. 

11. Law Enforcement and Resource Protection 

The staff of the Complex recognizes the obligation that has been 

entrusted to them--the care of valuable natural and cultural 

resources--and they take this responsibility very seriously. 

Law enforcement on the Refuges is used both for protection and for 

prevention. Used for protection, law enforcement safeguards the 

visiting public, staff, facilities, and natural and cultural resources 

from criminal action, accidents, vandalism, and negligence. Used as 

prevention, law enforcement inhibits incidents from occurring by 

providing a law enforcement presence. 

The Complex has a law enforcement staff that consists of two fulltime refuge officers and one dual-function officer. These officers are 

responsible for all law enforcement issues on Sacramento River, 

Sacramento, Delevan, Colusa, and Sutter Refuges, and on Butte Sink 

and North Central Valley Wildlife Management Areas. Dual-function 

officers conduct law enforcement as a “collateral duty” in addition to 

their primary responsibility, such as an assistant refuge manager. 

The regional Northern California Zone Officer is also stationed at 

138 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

Sacramento Refuge and assists with law enforcement issues on the 

Complex. 

The refuge officers are responsible for coordinating their activities 

and cooperating with other local, State, and Federal law enforcement 

officials. 

12. Facilities Maintenance 

The Refuge shops, offices, and visitor parking areas require frequent 

maintenance and repair. Currently, the Refuges have eleven wage 

grade positions that are responsible for maintenance and operations. 

General road maintenance, including grading and mowing, is 

required on a number of the Refuge units to provide safe access 

through the Refuges. Some additional upland areas require mowing 

to reduce fire hazards, provide weed suppression, and provide access 

for maintenance or monitoring projects during the spring and 

summer months. 

Construction of building pad 

t Sacramento Refuge 

hoto by Steve Emmons 

a

P

In order to maintain the integrity of Refuges, it is critical to reduce 

trespass, dumping, and poaching on Refuge lands. It is the intent of 

the Service to maintain a positive working relationship with 

neighbors to reduce trespass, vandalism, and theft on adjacent 

landowner properties. To achieve these goals, the Refuges have 

fenced, signed, and gated the Refuges boundaries. This 

infrastructure helps to alleviate trespass problems. Annually, most 

Refuge units will require installation of some new posts due to 

vandalism. Information signs are maintained on each of the Refuges. 

13. Safety 

Safety is important both for the Complex staff and for Refuge 

visitors. Staff safety meetings are held monthly at the Refuge 

Headquarters. The intent of the meetings is to update and train 

personnel, as well as to resolve any safety concerns that arise. 

Sample topics include Lyme’s Disease, West Nile Virus, and 

Hantavirus Safety, Tractor Safety, Hazardous Dump Sites, Boating 

Comprehensive Conservation Plan 139 
Chapter 3 

Safety, CPR/First Aid, Hypothermia, Low visibility Driving, Heat 

Stress, and Respiratory Safety. 

The Complex has a Safety Plan, updated annually, that describes the 

safety program and the responsibilities of the refuge staff and 

volunteers. The Safety Plan has an extensive amount of safety 

information provided in the Appendices. A safety committee 

comprised of a collateral duty safety officer and five additional people 

meets regularly throughout the year to discuss safety issues and 

coordinate safety inspections. 

14. Cultural Resources 

From the late Pleistocene, more than 10,000 years ago, to present 

time, humans have occupied northern California and utilized its 

generous natural resources. Many diverse and complex cultures 

developed during this time, culminating in the Native American 

Tribes recorded by early ethnographers. 

Wintun (Nomlaki) occupied both banks of the Sacramento River and 

the valley and foothills west of the River. The northwest Maidu lived 

in the valley, east of the River, along Butte and Big Chico Creeks, 

and had territories extending into the eastern foothills and 

mountains. The southern-most Yana tribe (Yahi) occupied lands east 

of the River, north of the Big Chico Creek. The territories of these 

tribes overlapped seasonally. For example, during the summer 

months the Nomlaki moved from the alluvial plain of the Sacramento 

River onto the alluvial fan of adjacent eastern foothills, while Yahi 

and northwest Maidu moved east, into the southern Cascade and 

northern Sierra Nevada Mountains, respectively. These people fished 

for Chinook salmon and hunted for tule elk, pronghorn, black-tailed 

deer, rabbits, California quail, and waterfowl. They also harvested 

acorns and a variety of seeds, roots, tubers, and bulbs from native 

plants (Goldschmidt 1978; Johnson 1978; Riddlell 1978). 

Under natural conditions, the Colusa Basin, in which the Refuges are 

situated, was characterized by vernal pools, which supported large 

numbers of waterfowl in the winter. Topographic features of the area 

generally were not favorable for extended occupation by the 

indigenous tribes, although temporary camps may have resulted from 

hunting and gathering activities. 

Euro-American contact with native tribes in the region began with 

the Spanish Moraga expedition of 1808. In the 1820s, fur trappers, 

such as Jedediah Smith, were working in the area. By the 1830s, 

smallpox and malaria had decimated the native population. The 

following decades brought increasing colonization of the area and the 

beginnings of the modern agricultural pattern. 

American colonization of the Sacramento Valley began during the 

Mexican Rancho era. John Bidwell, Peter Lassen, and John Parrot 

140 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

were among those awarded a Mexican Land Grant, which included 

Rancho del Arroyo Chico, Rancho Bosquejo, and Rancho Llano Seco, 

respectively. Statehood came soon after gold was discovered by 

James Marshall at Sutter’s Mill on the American River. Thousands of 

fortune seekers immigrated to California and those supplying goods 

and services to the miners realized economic success. The early 

ranches and farms provided vital agricultural commodities which 

helped expand settlement. People and freight were transported by 

wagon and steamboat. Thirteen ferries were located along the 

Sacramento River between Red Bluff and Colusa. River travel by 

steamboat was a practical mode of transportation because river boats 

could efficiently transport agricultural freight and the valley oak 

forests and woodlands supplied an abundance of fuel to power these 

paddle-wheeled steam boats. Ferries, river boat landings, and 

bridges all played a key roll in the locations of towns and the 

development of a system of roads. Improved roads and the railroad 

system eventually replaced river boat travel. 

Agriculture was first and foremost the central economic force in the 

Sacramento Valley. Dry land grain farming was the earliest 

agricultural practice. Row crops, orchards, rice, and irrigated pasture 

flourished when abundant water from the Sacramento River and its 

tributaries irrigated the fertile alluvial soils of the floodplain and 

basins. Water was distributed to farms through a system of river and 

stream diversions and water delivery canals. The development of the 

centrifugal pump in the early 20th century facilitated the expansion of 

irrigated lands through ground water pumping. Finally, State and 

Federal water projects for land reclamation, irrigation and urban 

water supply, and flood control allowed for further agricultural and 

urban expansion and the industries that followed. 

Sacramento Refuge was established in 1937, encompassing the 

extensive holdings of the Spalding Ranch. A Civilian Conservation 

Corps (CCC) camp was assigned to the Refuge to transform the 

wheat and rice fields into a series of ponds for waterfowl. The CCC 

also began altering the ranch buildings for use as the Refuge 

Headquarters. For the most part, ranch buildings were torn down 

and the materials salvaged. The CCC extensively altered the original 

1910s ranch house in 1939 to create a “modern” residence (Quarters 

No. 1) for the refuge 

manager. The garage was 

also remodeled from an 

existing building in 1939. A 

lookout tower, two service 

buildings, carpenter shop, 

water tower, a “caretaker’s” 

residence (Quarters No. 2), 

and an office were 

constructed between 1937 

and 1942. 

Refuge manager’s 

residence (1939) 

USFWS photo 

Comprehensive Conservation Plan 141 
Sacramento Refuge buildings (1940) 

Chapter 3 

In 1980, the Service prepared a determination of eligibility for the 

buildings at the Sacramento Refuge headquarters for inclusion in the 

National Register of Historic Places (NRHP) based on its association 

with the CCC and early development of the Refuge (Criterion A) 

(Osugi 1980; Speulda and Donovan 2003). The California State 

Historic Preservation Office concurred with the Service’s 

determination of eligibility, and it was subsequently forwarded to the 

Keeper of the NRHP for review. Although the Keeper found that the 

buildings were “undistinguished,” he concurred that the Complex as 

a whole was eligible as a district under Criterion A because of its 

association with the CCC and noted that “this camp is of exceptional 

significance in the field of conservation...[it] served as the 

headquarters for several wildlife conservation areas within the 

Sacramento River basin and is an important survivor from the early 

period of the Federal Government’s involvement in wildlife 

conservation.” 

Although formal nomination of the district to the NRHP was never 

completed, the buildings remain “eligible” and therefore continue to 

be treated as historic properties. Of the original buildings and 

structures evaluated for inclusion in the NRHP, one storage building 

was destroyed by fire in 1984; three grain bins rusted out and were 

removed in 1990; the flagpole fell down and was removed in 1998; and 

one residence and the garage were demolished in 2004 after 

development of a Memorandum of Agreement in coordination with 

the State of California, Office of Historic Preservation. The seven 

remaining buildings and structures include a residence, equipment 

storage building, office, water tower, observation tower, carpenter 

shop, and CCC Camp sign. 

USFWS photo 

The exterior of the remaining residence has been altered over the 

years, although the interior retains many of the CCC-era 

workmanship elements. The office has been modified extensively over 

the past 65 years. Although still retaining most of their original 

features, the equipment storage building, water tower, observation 

tower, and carpenter shop are in need of extensive repairs to 

142 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

The Refuge Environment 

maintain their functionality and historic integrity. The CCC Camp 

sign is in storage and the sign support structure remains at the 

original site. 

In addition to the Sacramento Refuge CCC Headquarters Complex 

district evaluation, cultural resource investigations conducted to date 

on the Refuges have included three narrow surveys that examined 

small portions of Delevan, Colusa, and Sutter Refuges prior to the 

occurrence of management activities being conducted on specific 

project locations. These surveys generally consisted of single person 

meandering pedestrian transects which covered the project areas. No 

cultural resources were identified during these surveys. 

The Service, like other Federal agencies, is legally mandated to 

inventory, evaluate, and protect cultural resources located on those 

lands that the agency owns, manages, or controls. The Service’s 

cultural resource policy is delineated in 614 FW 1-5 and 126 FW 1-3 

of the Service Manual. Field stations initiate the cultural resource 

review and compliance process by contacting the Regional Historic 

Preservation Officer⁄Regional Archaeologist (RHPO/RA). The 

RHPO/RA determines whether the proposed undertaking has the 

potential to impact cultural resources, identifies the “area of potential 

effect,” determines the appropriate level of scientific investigation 

necessary to ensure legal compliance, and assists the field station in 

initiating consultation with the pertinent State Historic Preservation 

Office (SHPO) and federally recognized Tribes. 

15. Social and Economic Environment 

15.1. Transportation 

Major transportation routes in the vicinity of the Refuges include 

Interstate 5, State highways 99, 45, 162, 20, and county route 99W. 

Many small paved county roads provide for local transportation, 

offering service access to local agricultural activities. These, and the 

large interstate and highways, provide access to Refuge visitor 

contact stations and parking lots. There are no alternative 

transportation systems that provide access to the Refuges. 

American coot 

Photo by Steve Emmons 

Comprehensive Conservation Plan 143 
Chapter 3 

15.2. Employment 

California has a $1.4 trillion gross state product, which makes it the 

largest state economy in the nation and the fifth largest economy in 

the world (California Department of Transportation 2005). The 2005­

2025 County-Level Economic Forecast (California Department of 

Transportation 2005) reported that the state has 14.9 million wage 

and salary jobs. In 2004, 139,500 jobs were created, 97 percent of 

which came from the non-farm sector. The unemployment rate 

declined to 6.2 percent. The per capita income in California is $34,220 

and the average salary per worker is $49,690. Employment growth is 

expected to increase over the next several years. 

The unemployment rate is one of the best ways to measure the 

economic health of a region. The Great Valley Center’s report on 

“Assessing the Region Via Indicators: The Economy” (2005), states 

that while unemployment in the Central Valley remains substantially 

higher than the rest of California, the difference has decreased 

slightly since 1998. From 1994 to 1998, the Central Valley’s 

unemployment rate averaged 11.9 percent, which was 4.8 percentage 

points higher than the State rate. From 1999 to 2003, the Central 

Valley unemployment averaged 10 percent, which was 4.2 percentage 

points higher than the State rate. 

Agriculture is a critical part of the economy in Glenn County. In 2004, 

agriculture was responsible for 20 percent of total employment, and 

total crop production was valued at over $327 million (California 

Department of Transportation 2005). State/local government is the 

largest employment sector and agriculture is the second (employing 

1,520 people) (California Department of Finance 2002). The 2005-2025 

County-Level Economic Forecast (California Department of 

Transportation 2005) reported that Glenn County had 7,580 wage and 

salary jobs increasing 5.1 percent (369 jobs) from the previous year. 

Non-farm employment added 142 jobs, while farm employment added 

227 jobs. The unemployment rate, declined to 9.4 percent in 2004. 

Employment growth is expected to increase over the next several 

years, as a result of growth in the non-farm sector. 

Colusa County is the most productive rice growing county in the 

nation (New Valley Connexions 2001). Agriculture is the largest 

employment sector (employing about 2,540 people) and State/local 

government is second (California Department of Finance 2002). The 

2005-2025 County-Level Economic Forecast (California Department 

of Transportation 2005) reported that Colusa County had 7,480 wage 

and salary jobs increasing 1 percent (77 jobs) from the previous year. 

Non-farm employment added 42 jobs, while farm employment added 

35 jobs. The unemployment rate declined to 13.6 percent in 2004. 

Employment growth is expected to increase over the next several 

years. 

144 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

In Sutter County, trade and services is the largest employment 

sector, agriculture is second (employing 6,200 people), and State/local 

government is third (California Department of Finance 2002). The 

2005-2025 County-Level Economic Forecast (California Department 

of Transportation 2005) reported that Sutter County had 26,940 wage 

and salary jobs increasing 0.6 percent (160 jobs) from the previous 

year. Non-farm employment added 440 jobs, while farm employment 

lost 280 jobs. The unemployment rate declined to 10.6 percent in 

2004. Employment growth is expected to increase over the next 

several years, as a result of growth in the non-farm sector. 

15.3. Local Economy 

Agriculture is the dominant economic enterprise in the northern 

Sacramento Valley and provides nearly 20 percent of the jobs in the 

Central Valley. The diversity of crops grown in the Sacramento 

Valley reflects the diversity of soils, climate, cultural and economic 

factors. Glenn County’s major crops include rice, almonds, prunes, 

and corn; Colusa County’s include rice, tomatoes, and almonds; and 

Sutter County’s include rice, plums, peaches, walnuts, and tomatoes. 

Countywide agricultural production values are $280.9 million for 

Glenn; $346 million for Colusa, and $343 million for Sutter (California 

Department of Finance 2002). 

The 2005-2025 County-Level Economic Forecast (California 

Department of Transportation 2005) reported that Glenn County’s 

per capita income is $21,210, and the average salary per worker is 

$30,780. Colusa County’s per capita income is $27,690, and the 

average salary per worker is $31,450. Sutter County’s per capita 

income is $26,940, and the average salary per worker is $32,150. 

The report “Banking on Nature 2006: The Economic Benefits to 

Local Communities of National Wildlife Refuge Visitation” (USFWS 

2007b) detailed the findings from 80 national wildlife refuges, 

including Sacramento Refuge. The Banking on Nature 2006 study 

included money spent for food and refreshments, lodging at motels, 

cabins, lodges or campgrounds, and transportation when it calculated 

the total economic activity related to refuge recreational use. 

According to the report (USFWS 2007b), Sacramento Refuge had 

over 137,430 visits in 2006. Refuge visitors enjoyed a variety of 

activities, including wildlife viewing, hiking, and migratory bird 

hunting. Non-residents accounted for about 127,408 or 93 percent of 

recreation visits and almost all of the visits were for non-consumptive 

recreations (129,257). Sacramento Refuge generated an estimated 

$2.4 million in total economic activity related to refuge recreational 

use with associated employment of 25 jobs, $773,500 in employment 

income and $391,100 in total tax revenue. Total expenditures were 

$1.8 million with non-residents accounting for $1.7 million or 96 

percent of total expenditures. Expenditures on hunting accounted for 

57 percent of all expenditures, and non-consumptive activities 

Comprehensive Conservation Plan 145 
Chapter 3 

accounted for 43 percent. Sacramento Refuge generated $2.78 of 

recreation-related benefits for every $1 of budget expenditure during 

2006. 

Cinnamon teal 

Photo by Mike Peters 

The report (USFWS 2007b) also states recreational visits to national 

wildlife refuges generate substantial economic activity. In 2006, 34.8 

million people visited refuges in the lower 48 states for recreation. 

Their spending generated almost $1.7 billion of sales in regional 

economies. As this spending flowed through the economy, nearly 

27,000 people were employed and $542.8 million in employment 

income was generated. In addition, refuge recreational spending 

generated about $185.3 million in tax revenue at the local, county, 

state and Federal level. About 82 percent of total expenditures are 

generated by non-consumptive activities on refuges. Fishing 

accounted for 12 percent and hunting 6 percent. Local residents 

accounted for 13 percent of expenditures while visitors coming from 

outside the local area accounted for 87 percent. 

15.4. Land Use and Zoning 

The Refuges are bordered primarily by private lands. Private lands 

are mostly agricultural land (rice, orchards, row crops), with some 

private duck-hunting clubs, farmsteads, businesses, trailer parks, and 

isolated homes. 

Each of the three counties in which the Refuges are located has its 

own General Plan that outlines land use policies. The portions of 

Glenn, Colusa, and Sutter counties’ General Plans that relate to 

management of the Refuges are summarized in Appendix M. 

15.5. Demographics 

In the first 150 years of statehood, California grew from fewer than 

100,000 citizens in 1850 to almost 34 million in 2000 (California 

Department of Finance 2002). Between 1950 and 2000 alone, 

California’s population increased by 200 percent (California 

Department of Finance 2002). If California continues to add nearly 

500,000 persons each year, by 2012, the population could easily 

146 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
The Refuge Environment 

exceed 40 million. The 50-million mark will be passed sometime 

between 2030 and 2040 if current growth rates persist (California 

Department of Finance 2002). 

The Central Valley has been one of the fastest growing areas in 

California during the last few decades. As of July 1997, the Central 

Valley had seventeen percent of the State’s population (Munroe and 

Jackman 1999). 

In 2005, Glenn County’s population was 28,197 and is expected to 

increase to 32,000 residents by 2020 (California Department of 

Finance 2005). The racial makeup of the county was 71.8 percent 

white, 29.6 percent Hispanic, 3.4 percent Asian, 2.1 percent Native 

American, 0.6 percent African American, with the remaining 

percentage from other races (Percentage total can be greater than 

100 percent because Hispanics can be counted in multiple races, U.S. 

Census Bureau 2000). The estimated median family income was 

$32,107. 

Colusa County is home to 20,800 residents and is projected to 

increase to 26,000 residents by 2020 (California Department of 

Finance 2005). The racial makeup of the county was 64.3 percent 

white, 46.5 percent Hispanic, 2.3 percent Native American, 1.2 

percent Asian, 0.5 percent African American, with the remaining 

percentage from other races (Percentage total can be greater than 

100 percent because Hispanics can be counted in multiple races, U.S. 

Census Bureau 2000). The estimated median family income was 

$35,062. 

Sutter County’s population was 88,945 people and is expected to 

increase to 112,000 people by 2020 (California Department of Finance 

2005). The racial makeup of the county was 67.5 percent white, 22.2 

percent Hispanic, 11.3 percent Asian, 1.9 percent African American, 

1.6 percent Native American, with the remaining percentage from 

other races (Percentage total can be greater than 100 percent 

because Hispanics can be counted in multiple races, U.S. Census 

Bureau 2000). The estimated median family income was $38,375. 

Greater white-fronted goose 

Photo by Steve Emmons 

Comprehensive Conservation Plan 147 
Chapter 3 

148 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

Chapter 4 Planned Refuge 

Management and Programs 

Overview of Goals, Objectives, and Strategies 

One of the most important parts of the CCP process is the 

development and refinement of the Refuges’ vision and goals. This 

section contains the primary goals that will define the management 

direction of the Refuges for the next 15 years. In addition, as part of 

the CCP, the Refuges are expected to develop objectives and 

strategies that, together, will help achieve the goals. Goals are broad 

statements of the desired future conditions for refuge resources. 

Refuge goals may or may not be feasible within the 15-year time 

frame of the CCP. Whenever possible, objectives are quantified 

statements of a standard to be achieved or work to be accomplished. 

They should be specific, measurable, achievable, results-oriented, and 

time-fixed, and should be feasible within the 15-year lifespan of the 

CCP. Strategies are specific actions, tools, or techniques that 

contribute toward accomplishing the objective. In some cases, 

strategies describe specific projects in enough detail to assess 

funding and staffing needs. 

The five goals of the Sacramento, Delevan, Colusa, and Sutter 

National Wildlife Refuges are outlined below to provide a context for 

the proposed management direction. 

Goal 1: Wildlife and Habitat Goal 

Conserve, manage, restore, and enhance habitats and 

associated plant and wildlife species, with an emphasis on 

supporting an abundance and natural diversity of wintering 

and migrating waterfowl, shorebirds, birds of prey, and 

songbirds. 

Goal 2: Threatened and Endangered Species Goal 

Conserve, manage, restore, and enhance threatened and 

endangered species and their habitats including vernal pool 

plants and invertebrates, and giant garter snakes. 

Goal 3: Visitor Services Goal 

Provide visitors of all ages and abilities with quality wildlifedependent recreation (hunting, wildlife observation, 

photography, environmental education, and interpretation), 

and volunteer opportunities to enhance public appreciation, 

understanding, and enjoyment of fish, wildlife, habitats, and 

cultural resources. 

Comprehensive Conservation Plan 149 
Chapter 4 

Goal 4: Partnership Goal 

Promote partnerships to preserve, restore, and enhance a 

diverse, healthy, and productive ecosystem in which the 

Refuges play a key role. 

Goal 5: Resource Protection Goal 

Adequately protect and maintain all natural and cultural 

resources, staff and visitors, equipment, facilities, and other 

property on the Refuges. 

Organization 

Each objective and strategy are given a unique numeric code for easy 

reference. Objectives have a two-digit code (e.g., 1.1, 1.2, 2.1, 2.2). The 

first digit corresponds to the goal to which the objective applies. The 

second digit is sequential. Similarly, each strategy has a three-digit 

code (e.g., 1.1.1, 1.1.2, 2.1.1, 2.1.2). The first and second digits refer to 

the appropriate goal and objective, respectively. The third digit is 

sequential. 

Refuge Management Goals, Objectives, and Strategies 

1. Wildlife and Habitat Goal 

Conserve, manage, restore, and enhance habitats and 

associated plant and wildlife species, with an emphasis on 

supporting an abundance and natural diversity of wintering 

and migrating waterfowl, shorebirds, birds of prey, and 

songbirds. 

1.1. Managed Wetland Habitat Objective 

Collectively on the four Refuges, actively manage 16,914 wetland 

habitat acres to provide 80 to 90 percent seasonally flooded wetlands 

and 10 to 20 percent summer wetlands, starting in 2008. Seasonally 

flooded wetlands will contain 5 to 50 percent tall emergent cover, >50 

percent desirable forage plant species cover, and an average water 

depth of 12 inches (range of 1 to 36 inches). Summer wetlands units 

will contain 40 to 70 percent cover of desirable submergent or 

floating-leaved emergent species. At least 50 percent of summer 

wetland units will have 30 to 80 percent tall emergent cover and 

average water depths of 24 inches (range of 12-36 inches) during 

May-October and <18 inches during November-April. 

Rationale: Wetlands support the greatest abundance and diversity of 

wildlife on the Refuges. Freshwater wetlands have declined by 90 to 

95 percent in the Central Valley (Holland 1978; 1998; Gilmer et al. 

1982; Frayer et al. 1989; Kempka and Kollasch 1990). The North 

American Waterfowl Management Plan (USFWS et al. 1986, 1998) 

and the Central Valley Joint Venture (CVJV) Implementation Plan 

(CVJV 2006) address population and habitat objectives for healthy 

waterfowl populations. This objective also helps to achieve Central 

150 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

Valley and Bay-Delta Region Conservation Actions C and L in the 

California Wildlife Action Plan (CDFG 2005c). Refuge management 

strategies will support these objectives. Managed wetlands are an 

essential component upon which significant numbers of waterfowl, 

waterbirds, shorebirds, other birds, threatened and endangered 

species rely. 

Climate change is already affecting wildlife throughout the state 

(Parmesan and Galbraith 2004), and its effects will continue to 

increase, it has particular significance for this region’s major river 

systems. For the Central Valley, this means more intense winter 

flooding, greater erosion of riparian habitats, and increased 

sedimentation in wetland habitats (Field et al. 1999, Hayhoe et al. 

2004). Hotter, drier summers, combined with lower river flows, will 

dramatically increase the water needs of both people and wildlife. 

This is likely to translate into less water for wildlife, especially fish 

and wetland species. 

Managed Wetland Habitat Strategies 

1.1.1. Incorporate wetland management into annual habitat 

management planning process. 

1.1.2. Actively manipulate water levels on seasonally flooded 

wetlands and summer wetlands consistent with annual Habitat 

Management Plans. 

1.1.3. Restore, rehabilitate or enhance at least 10 percent of the 

wetland habitat annually. 

1.1.4. Use mowing, disking, deleveling, prescribed fire 

(approximately 1,500 acres/year), herbicides, and grazing to 

manage and enhance wetland habitat. 

1.1.5. Maintain water control infrastructure. 

1.1.6. Conduct and evaluate wetland vegetation surveys annually. 

1.1.7. Conduct and evaluate regular wildlife surveys to assess 

wildlife use of wetland habitats. 

1.1.8. Support and facilitate management-oriented research on 

wetland habitat, including monitoring the impacts of climate 

change. 

1.1.9. Hire full-time wildlife biologist, purchasing agent, office 

automation clerk, tractor operator, prescribed fire specialist, fire 

budget technician, and two engineering equipment operators to 

implement wetland habitat management an support other habitat 

objectives. 

Comprehensive Conservation Plan 151 
Chapter 4 

1.1.10. Hire one full-time computer specialist to implement wetland 

habitat management and support Goal’s 1-5. 

1.2. Vernal Pool/Alkali Meadow Habitat Objective 

Protect and enhance 4,021 acres of vernal pool/alkali meadow habitat 

comprised of >60 percent native plant species cover by 2013. 

Rationale: In combination, vernal pools and alkali meadow habitats 

support the greatest percentage of rare, endemic, and Federal and 

State listed species on the Refuges. Approximately 75 percent of all 

vernal pools in the Central Valley were lost by 1997 (Holland 1978, 

1998). Early losses were primarily related to conversion to 

agriculture croplands. Losses that are more recent have been a result 

of conversion of historic cattle grazing lands to other uses and 

widespread urbanization (USFWS 1998, 2005). Vernal pool/alkali 

meadow conservation, management, and restoration are among the 

mandated purposes of the Refuges. This objective also helps to 

achieve Central Valley and Bay-Delta Region Conservation Action C 

in the California Wildlife Action Plan (CDFG 2005c). 

Vernal pool on Sacramento Refuge 

Photo by Joe Silveira 

Vernal Pool/Alkali Meadow Habitat Strategies 

1.2.1. Incorporate vernal pool/alkali meadow management into 

annual habitat management planning process. 

1.2.2. Use prescribed fire (approximately 200 acres/year), 

herbicides, and grazing as primary methods to reduce and control 

non-native and invasive plant species in vernal pool/alkali meadow 

habitat. 

1.2.3. Protect hydrology of vernal pool/alkali meadow habitat by 

controlling runoff from surrounding flooded lands. 

1.2.4. Restore Tract 24.12 (32 acres) and Tract 26 (60 acres) to 

vernal pool/alkali meadow habitat on Colusa Refuge. 

152 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

1.2.5. Restore Tract 1.1 (73 acres) to vernal pool/alkali meadow 

habitat on Delevan Refuge. 

1.2.6. Restore additional acres of vernal pool/alkali meadow habitat 

as opportunities arise. Use plant materials (i.e., seeds, cuttings) 

derived from local ecotypes to construct natural plant 

communities, which may support locally rare native plants, 

endemic species, and threatened and endangered species. 

1.2.7. When restoring vernal pool/alkali meadow habitats, 

implement restoration for species identified in the vernal pool 

recovery plan when and where possible (refer to Threatened and 

Endangered Species Strategies). 

1.2.8. Conduct and evaluate regular wildlife surveys to assess 

wildlife use of vernal pool/alkali meadow habitats. 

1.2.9. Conduct and evaluate periodic vernal pool/alkali meadow 

vegetation surveys. 

1.2.10. Support restoration and management-oriented research on 

vernal pool/alkali meadow habitats. 

1.3. Grassland Habitat Objective 

Protect and enhance 1,267 acres of grassland habitat comprised of 

>60 percent native plant species cover by 2013. 

Rationale: Perennial and annual grasslands provide numerous 

important habitat components, including foraging areas, nesting, 

thermal and escape cover, for a variety of wildlife species on the 

Refuges. Less than one percent of California’s original grasslands 

remain (Huenneke 1989) due to conversion to cropland, development, 

wildfire suppression, and introduction of nonnative plant species. The 

Grassland Bird Conservation Plan (CPIF 2000) has addressed 

population and habitat objectives for healthy grassland bird 

populations. Refuge management strategies will support these 

objectives. This objective also helps to achieve Central Valley and 

Bay-Delta Region Conservation Action C and Statewide 

Conservation Action H in the California Wildlife Action Plan (CDFG 

2005c). 

Grassland Habitat Strategies 

1.3.1. Incorporate grassland management into annual habitat 

management planning process. 

1.3.2. Conserve, protect, enhance, and restore a variety of perennial 

and annual grasslands, where appropriate, based on soils, 

hydrology, or other features. 

Comprehensive Conservation Plan 153 
Chapter 4 

1.3.3. Use mowing, disking, prescribed fire (approximately 200 

acres/year), herbicides, and grazing, or other appropriate 

treatments to reduce and control non-native and invasive plant 

species, enhance and maintain native species composition, and 

provide a mix of tall or short grassland structure. 

1.3.4. Protect hydrology of grassland habitat by controlling runoff 

from surrounding flooded lands. 

1.3.5. Restore Tract 44.3 (40 acres) to native grasslands on Delevan 

Refuge. 

1.3.6. Restore additional acres to native grasslands using plant 

materials (i.e., seeds, cuttings) derived from local ecotypes as 

opportunities arise. 

1.3.7. Enhance topographic features for selected wildlife species 

(burrowing owl, etc.). 

1.3.8. Conduct and evaluate regular wildlife surveys to assess wildlife 

use of grassland habitats. 

1.3.9. Conduct and evaluate periodic grassland vegetation surveys. 

1.3.10. Support management-oriented research on grassland habitats. 

1.4. Riparian Habitat Objective 

Protect and enhance 581 acres of riparian habitat comprised of >80 

percent native woody vegetation and herbaceous cover by 2013. 

Rationale: Wetlands and riparian forests once covered about five 

million acres of the Central Valley before intensive settlement began 

in the late 1800s. Flood-control and subsequent conversion of natural 

wetlands to agricultural production have reduced these habitats to 

less than one-tenth their former extent (Dahl 1990). Less than two 

percent of the pre-1850 acreage of riparian forest remains, with 

virtually all of the Valley oak forest type gone (Bay Institute 1998). 

Riparian forests and other riparian plant communities of California’s 

Central Valley provide habitat for a diversity of resident and 

migratory terrestrial and aquatic wildlife, including rare and 

endangered species (Gaines 1974, 1977; Moyle 2002; Riparian Habitat 

Joint Venture 2004; Roberts et al. 1977; Small et al. 2000) The 

Partners in Flight North American Landbird Conservation Plan 

(Rich et al. 2004), the California Partners in Flight/Riparian Habitat 

Joint Venture Riparian Bird Conservation Plan (2004), and CVJV 

Implementation Plan (2006) identify focal species and habitat 

conservation and restoration needs for Central Valley birds. Refuge 

management strategies will support these objectives. This objective 

also helps to achieve Central Valley and Bay-Delta Region 

154 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

Conservation Actions C and L in the California Wildlife Action Plan 

(CDFG 2005c). 

Riparian Habitat Strategies: 

1.4.1. Incorporate riparian management into annual habitat 

management planning process. 

1.4.2. Enhance riparian habitat by planting indigenous native trees 

and shrubs using local ecotypes when practicable and feasible on 

Colusa Refuge along Powell Slough and Tract 14 (5 acres). 

1.4.3. Restore understory riparian habitat by planting indigenous 

native grasses, sedges, and forbs on Colusa Refuge. 

1.4.4. Enhance riparian habitat by eliminating or reducing nonnative and invasive trees and shrubs through manual removal and 

herbicide application. 

1.4.5. Maintain cottonwood willow forest on Sacramento Refuge 

Tract 31.1 (Sherwood Forest) to provide habitat for breeding and 

migratory birds. 

1.4.6. Conduct and evaluate regular wildlife surveys to assess 

wildlife use of riparian habitats. 

1.4.7. Conduct and evaluate periodic riparian vegetation surveys. 

1.4.8. Support management-oriented research on riparian habitats, 

including monitoring the impacts of climate change. 

1.5. Sutter Bypass Management Objective 

By 2008, actively manage 1,500 acres within the Sutter Bypass 

portion of Sutter Refuge to help prevent excessive accumulation of 

woody vegetation that may impact flood water conveyance 

capabilities. Begin implementation of a “Tree Reduction Operations 

Plan - Tract 1 Sutter National Wildlife Refuge” (Appendix P). 

Rationale: The Sutter Bypass (Bypass) was constructed to provide 

conveyance for floodwaters. The Refuge, in cooperation with the 

Department of Water Resources (DWR), Sutter County, and other 

interested parties, will implement Best Management Practices 

(BMPs) listed below to avoid reduction in floodwater conveyance 

capacity in the Bypass. The focus of the tree/shrub reduction efforts 

will continue to be within the managed wetland units, especially those 

within the center “alley” of Sutter Refuge. Groups of trees/shrubs 

with an east-west orientation will be considered the highest priority 

for removal and maintenance throughout the Bypass. Because the 

“Northwest Grove” in the Tract 1 upland has filled in extensively 

since the 1960’s, a specific operational plan focusing on tree and 

understory reduction in that area has been developed (Appendix P). 

Comprehensive Conservation Plan 155 
Chapter 4 

The trees bordering the east and west borrow channels along the 

entire length of the Refuge within the Bypass will remain. 

Sutter Bypass Management Strategies: 

1.5.1. Work closely with DWR, Sutter County, and Central Valley 

Flood Protection Board (aka State Reclamation Board) staff on 

floodplain management issues at Sutter Refuge. Provide each 

agency with copies of annual habitat management plans. 

1.5.2. Implement BMPs throughout the managed wetlands in the 

Bypass. Woody vegetation will comprise no more than five 

percent of the aerial cover between the bordering tree lines. 

Management efforts will be adaptive and utilize the following: 

 Within wetland management units, focus efforts on groups or 

lines of trees running perpendicular to flood flows using 

mechanical, chemical, livestock grazing or prescribed fire 

removal/maintenance methods. 

 Within wetland management units, target saplings when 

disking and use herbicides and/or mechanical removal to 

control mid-sized trees/shrubs (trees established after the 

2001 tree removal effort). 

 Work cooperatively with DWR to spray herbicide on regrowth of selected woody vegetation. 

 Control new woody growth (established after the 2005 

removal work) between the “Northwest Grove” and the road 

to the northeast gate using mechanical, chemical, livestock 

grazing or prescribed fire. 

 Remove all non-native trees throughout the Bypass portion of 

the Refuge. 

 Monitor the effects of vegetation removal/control on wildlife 

and habitat. 

1.5.3. Work cooperatively with DWR and others to begin 

implementation of the “Tree Reduction Operations Plan-Tract 1 

Sutter National Wildlife Refuge” (Appendix P) in an effort to 

improve flood flows through the “Northwest Grove”. 

1.5.4. Maintain the forests on the east and west borrow channels as 

habitat for migratory birds, including western yellow-billed 

cuckoos, at 2006 levels. Do not allow the forests to expand into the 

adjacent wetlands. 

156 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Blue morph snow goose 

Photo by Mike Peters 

Planned Refuge Management 

1.6. Wintering Waterfowl Objective 

Conduct eleven annual and periodic surveys in order to assess trends 

in the abundance, distribution, recruitment, and health of wintering 

waterfowl on the Refuges, Central Valley, and Pacific Flyway. 

Rationale: Migratory birds are Federal trust species under the 

jurisdiction of the Service. Many species of migratory and resident 

birds depend on wetlands for winter habitat. Their conservation, 

management, and restoration are among the mandated purposes of 

the Refuges. Freshwater wetlands have declined by 90 to 95 percent 

in the Central Valley (Holland 1978; Gilmer et al. 1982; Frayer et al. 

1989; Kempka and Kollasch 1990). The North American Waterfowl 

Management Plan (USFWS et al. 1986, 1998), CVJV Implementation 

Plan (CVJV 2006), and Pacific Flyway Management Plans (Pacific 

Flyway Council 2007) address population and habitat objectives for 

healthy waterfowl populations. Refuge management strategies will 

support these objectives. The Refuges provide wintering habitat for 

waterfowl. Monitoring is necessary to determine population status, 

assess trends, and identify habitat use, as well as restoration and 

management needs. 

Wintering Waterfowl Strategies: 

1.6.1. Conduct regular wildlife surveys on Refuges one to two times 

a month. 

1.6.2. Coordinate with Pacific Flyway entities including Division of 

Migratory Bird Management (DMBM), California Department of 

Fish and Game (CDFG), U.S. Geological Survey (USGS) National 

Wildlife Health Lab, and other organizations to conduct survey 

and monitoring efforts. 

1.6.3. Conduct and report results from annual fall and winter 

waterfowl surveys, including special tule goose, white-fronted 

goose, dark goose, white goose, and midwinter waterfowl surveys. 

1.6.4. Conduct periodic white-goose species composition surveys. 

Comprehensive Conservation Plan 157 
1.6.5. Annually monitor abundance and distribution of Aleutian 

cackling geese in the Sacramento Valley. 

1.6.6. Collect data on age ratios of Arctic nesting geese for annual 

Flyway Productivity of Geese and Swans Report. 

1.6.7. Monitor and control avian disease outbreaks. 

1.6.8. Conduct or facilitate banding and marking of wintering 

waterfowl for population assessment. 

1.6.9. Support management-oriented research on wintering 

waterfowl. 

1.7. Breeding Waterfowl Objective 

Implement four monitoring surveys annually for breeding waterfowl on 

wetland habitats of the Refuges. 

Rationale: Migratory birds are Federal trust species under the 

jurisdiction of the Service. Many species of migratory and resident 

birds depend on wetlands for breeding habitat. Their conservation, 

management, and restoration are among the mandated purposes of 

the Refuges. Freshwater wetlands have declined by 90-95 percent in 

the Central Valley (Holland 1978, 1998, Gilmer et al. 1982, Frayer et 

al. 1989, Kempka and Kollasch 1990). The North American Waterfowl 

Management Plan (USFWS et al. 1986, 1998) and the CVJV 

Implementation Plan (CVJV 2006) address population and habitat 

objectives for healthy waterfowl populations. Refuge management 

strategies will support these objectives. The Refuges provide 

breeding habitat for waterfowl. Monitoring is necessary to determine 

population status, assess trends, and to identify habitat use as well as 

restoration and management needs. 

Breeding Waterfowl Strategies: 

1.7.1. Conduct regular wildlife surveys on Refuges one to two times 

a month. 

1.7.2. Conduct pre-season waterfowl banding in accordance with the 

Pacific Flyway Project, to meet or exceed established quotas. 

1.7.3. Maintain and monitor wood duck boxes on the Refuges. 

1.7.4. Evaluate Refuge waterfowl nesting, brood rearing, and 

molting habitat. 

1.7.5. Monitor and control avian disease outbreaks. 

1.7.6. Support management-oriented research on breeding 

waterfowl. 

Chapter 4 

158 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

1.8. Shorebird Objective 

Conduct annual (two) and periodic surveys in order to assess trends 

in the abundance, distribution, and health of shorebirds on the 

Refuges and in the Central Valley. 

Rationale: Migratory birds are Federal trust species under the 

jurisdiction of the Service. Many species of migratory and resident 

birds depend on wetlands for winter habitat. Freshwater wetlands 

have declined by 90 to 95 percent in the Central Valley (Holland 1978, 

1998; Gilmer et al. 1982; Frayer et al. 1989; Kempka and Kollasch 

1990). The U.S. Shorebird Conservation Plan, Southern Pacific 

Shorebird Conservation Plan (Hickey et al. 2003), and CVJV 

Implementation Plan (CVJV 2006) addresses population and habitat 

objectives for healthy shorebird populations. Refuge management 

strategies will support these objectives. The Refuges provide 

wintering, migration, and breeding habitat for shorebirds. 

Monitoring is necessary to determine population status, assess 

trends, and identify habitat use, as well as restoration and 

management needs. 

Greater yellowlegs 

Photo by Steve Emmons 

Shorebird Strategies: 

1.8.1. Conduct regular wildlife surveys on Refuges one to two times 

a month. 

1.8.2. Coordinate and conduct shorebird surveys with Central 

Valley Joint Venture. 

1.8.3. Monitor and control avian disease outbreaks. 

1.8.4. Support management-oriented research on shorebirds. 

1.8.5. Manage wetlands to optimize shorebird use during peak use 

times, such as spring migration. 

Comprehensive Conservation Plan 159 
Chapter 4 

1.9. Other Waterbird Objective 

Conduct three surveys annually in order to assess trends in the 

abundance, distribution, and health of other waterbirds on the 

Refuges. 

Rationale: Migratory birds are Federal trust species under the 

jurisdiction of the Service. Many species of migratory and resident 

birds depend on wetlands for winter habitat. Freshwater wetlands 

have declined by 90 to 95 percent in the Central Valley (Holland 1978, 

1998; Gilmer et al. 1982; Frayer et al. 1989; Kempka and Kollasch 

1990). The North American Waterfowl Management Plan (USFWS et 

al. 1986, 1998) and the CVJV Implementation Plan (CVJV 2006) 

address population and habitat objectives for focal species of 

waterbirds. Refuge management strategies will support these 

objectives. The Refuges provide breeding and wintering habitat for 

egrets, herons, rails, ibises, grebes, and other waterbirds. Monitoring 

is necessary to determine population status, assess trends, and 

identify habitat use, as well as restoration and management needs. 

Other Waterbird Strategies: 

1.9.1. Conduct regular wildlife surveys on Refuges one to two times 

a month. 

1.9.2. Monitor colonial waterbird rookery locations, size, and 

reproductive success. 

1.9.3. Conduct periodic surveys with CDFG for selected species, 

including sandhill crane. 

1.9.4. Monitor and control avian disease outbreaks. 

1.9.5. Support management-oriented research on waterbirds. 

1.9.6. Manage wetlands to optimize nesting and foraging habitat 

and successful breeding of waterbirds. 

1.10. Other Bird Objective 

Conduct six surveys annually in order to assess trends in the 

abundance, distribution, and health of landbird birds on the Refuges. 

Rationale: Migratory birds are Federal trust species under the 

jurisdiction of the Service. The Refuges provide habitat for migratory 

and resident birds. Monitoring is necessary to determine population 

status, assess population trends, determine causes for poor 

productivity, identify solutions, determine habitat restoration needs, 

and assess restoration success. 

Other Bird Strategies 

1.10.1. Conduct regular wildlife surveys on Refuges one to two times 

a month. 

160 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

1.10.2. Conduct periodic surveys with cooperating agencies for 

selected species, including tri-colored blackbird, yellow-billed 

cuckoo, and burrowing owl. 

1.10.3. Conduct golden eagle nest success survey at Sacramento 

Refuge. 

1.10.4. Conduct pheasant brood surveys at Sacramento, Delevan, and 

Colusa Refuges. 

1.10.5. Monitor and control avian disease outbreaks. 

1.10.6. Support management-oriented research on other birds. 

1.11. Anadromous Fisheries and Native Fisheries Objective 

By 2013, annually implement BMPs and water management 

strategies to provide for native fish life cycle needs on the Refuges. 

Rationale: The Service and the Refuge System each identify 

anadromous fish conservation in their mission statements. The 

Sacramento River system supports four distinct salmon runs making 

Chinook salmon and Central Valley steelhead important ecological, 

recreational, and commercial fisheries. The east and west Sutter 

Bypass canals are part of the lower Butte Creek and are tributary to 

the larger Sacramento River system. Adult salmon and steelhead 

migrate up the Sutter Bypass canals at various times of the year 

depending upon the run. 

Floodplain productivity is important to immature salmonids and 

other native fishes that escape from large predatory fish in shallow 

waters. When inundated, the relatively warmer waters of the 

floodplain become very productive and produce an abundance of prey. 

Juveniles also return through the Sutter Bypass and may use the 

canal and Refuge wetlands, depending upon flood conditions. 

Anadromous Fisheries and Native Fisheries Strategies: 

1.11.1. Coordinate with Department of Water Resources (DWR) to 

keep the weirs clean in the Sutter Bypass. 

1.11.2. Obtain Central Valley Project Improvement Act (CVPIA) 

water delivery for Sutter Refuge. 

1.11.3. Continue to provide and monitor the flow-through water 

management system at Sutter Refuge to prevent entrapment of 

native fish. 

1.11.4. Maintain water conveyance systems on Refuges. 

Comprehensive Conservation Plan 161 
Chapter 4 

1.11.5. Implement BMPs for mosquito control and herbicide 

applications (IPM Plan, Appendix F) on Refuges. 

1.12. Exotic, Invasive Species Control Objective 

Treat exotic invasive species using prescribed fire, grazing, herbicide 

treatment, mowing, disking, or other proven techniques on 8,000 

acres of the Refuges annually as described in the Integrated Pest 

Management Plan (Appendix F). 

Rationale: Invasive non-indigenous (exotic) species have become the 

single greatest threat to the Refuge System and the Service’s wildlife 

conservation mission. More than eight million acres within the 

Refuge System are infested with invasive weeds (Audubon 2002). 

Invasive species cause widespread habitat degradation, compete with 

native species, and contribute significantly to the decline of trust 

species (USFWS 2002b). The National Strategy for Management of 

Invasive Species (USFWS 2002b) has been developed within the 

context of the National Invasive Species Management Plan, as called 

for by Presidential Executive Order 13112, and functions as the 

internal guidance document for invasive species management 

throughout the Refuge System. This Plan has four goals: 1) Increase 

the awareness of invasive species issues, both internally and 

externally; 2) Reduce the impacts of invasive species to allow the 

Refuge System to more effectively meet its fish and wildlife 

conservation mission and purpose; 3) Reduce invasive species impacts 

on the Refuge System’s neighbors and communities; and 4) Promote 

and support the development and use of safe and effective integrated 

management techniques to deal with invasive species. This objective 

also helps to achieve Central Valley and Bay-Delta Region 

Conservation Actions C and P in the California Wildlife Action Plan 

(CDFG 2005c). 

The Central Valley is occupied by a diversity and abundance of 

exotic, invasive species that are harmful because they crowd out or 

replace native species that are important to wildlife natural diversity 

and ecosystem function. These species often dominate old 

agricultural fields and early successional stages of restoration sites. 

In addition, some late successional stages of native vegetation are 

also dominated by these undesirable species. As a result, vegetation 

must be managed to control invasive exotic species so that species 

composition favors a diversity and abundance of native, indigenous 

plants. 

Exotic, Invasive Species Control Strategies: 

1.12.1. Annually evaluate invasive exotic species to be controlled 

(Table 6, Chapter 3). Locate, map, and monitor exotic species that 

may trigger a management response. 

162 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

1.12.2. Control invasive and exotic species using prescribed fire, 

grazing, herbicide treatment, mowing, disking or other proven 

techniques as identified in the IPM plan (Appendix F). 

1.12.3. Conduct, facilitate, and/or support research to identify 

invasive plant biology and ecology and to evaluate techniques for 

controlling invasive plant species. 

1.12.4. Hire one full-time wildlife biologist to implement invasive 

species management. 

1.13. Wildlife Sanctuary Objective 

Provide 11,152 acres (47 percent of the Refuges total acres) of 

wetland, vernal pool/alkali meadow, grassland, and riparian habitats 

as sanctuary (i.e. no public access) for general wildlife use, nesting, 

sensitive breeding sites, and plant populations by 2008. 

Rationale: Sanctuaries are areas on the Refuges that are closed to 

public use. They provide places where human-caused disturbances 

are reduced, thereby reducing the interruption of wildlife activities, 

such as foraging, resting, breeding, feeding nestlings, and other 

maintenance activities. Sanctuaries are especially important during 

high refuge visitor use periods. They are also important for wildlife to 

avoid predation by other wild animals, as they can devote less energy 

to avoiding humans and more to avoiding predators. Sanctuaries are 

areas where wildlife concentrate and reproduce, resulting in 

increased numbers of wildlife that can lead to more wildlifedependent public use in areas near the sanctuary. 

In some cases, short-term sanctuaries may be established to protect a 

sensitive nesting colony or site. These seasonal sanctuaries may 

impose public access restrictions at some nesting sites for species 

with a low tolerance for human disturbance (e.g. waterbird rookeries, 

tri-colored blackbird colonies, and golden eagle nest sites). 

Waterfowl loafing in wildlife sanctuary 

Photo by Mike Carpenter 

Comprehensive Conservation Plan 163 
Chapter 4 

Wildlife Sanctuary Strategies: 

1.13.1. Provide strategically located sanctuaries on the Refuges for 

wildlife to feed and rest with relatively little human disturbance. 

1.13.2. Provide sanctuaries to reduce human disturbance at sensitive 

fish, wildlife, and plant sites during the rearing, breeding, and 

growing seasons. 

1.14. Mosquito Management Objective 

Cooperatively monitor and manage pest mosquito species on 16,914 

acres of managed wetlands, as described in the IPM Plan (Appendix 

F), by 2008. 

Rationale: Local mosquito and vector control districts have identified 

a need to conduct mosquito monitoring and, if necessary, control 

activities on the Refuges in order to protect the public from any 

mosquito borne diseases. While mosquitoes are considered a nuisance 

because of their biting, some species are known vectors of serious 

diseases in California. There are primarily five mosquito species of 

concern potentially produced or harbored on the Refuges: Aedes 

melanimon, Aedes nigromaculis, Aedes vexans, Culex tarsalis, and 

Anopheles freeborni. 

The main diseases of concern for mosquito control programs in 

northern California are Western Equine Encephalitis (WEE), St. 

Louis Encephalitis (SLE), California Encephalitis, West Nile Virus 

(WNV), and malaria (Appendix F). Culex tarsalis is the main vector 

identified in the transmission of these diseases, with the exception of 

malaria, which is vectored by Anopheles freeborni mosquitoes. The 

other mosquito species listed above can also potentially transmit 

WEE, SLE, and WNV, but are less competent vectors compared to 

C. tarsalis. WEE and SLE have caused significant outbreaks of 

human disease (CA Dept. of Health Services 2003). Public concern 

over human health issues related to mosquito-borne disease has 

intensified on the west coast with the advance of WNV across the 

United States, and its detection in California in 2003. 

The Refuges have developed an IPM Plan (Appendix F) that outlines 

a risk-based, hierarchical approach to mosquito management. This 

approach uses an understanding of mosquito biology and ecology 

whereby intervention measures depend on continuous monitoring of 

mosquitoes. 

The IPM approach ensures legitimate human, fish, and wildlife health 

concerns are addressed. It incorporates a combination of using a 

combination of best management practices (BMPs) in managed 

wetlands (Kwasny et al. 2004), biological controls, and a select group 

of pesticides, if warranted. Treatment thresholds (i.e. adult and larval 

mosquito population levels, and disease activity) and appropriate 

corresponding responses are identified (USFWS 2005b). Under this 

164 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

program, if mosquito monitoring and disease surveillance indicate 

that human health thresholds are exceeded, the use of larvicides, 

pupicides, and/or adulticides may become necessary. In some cases, 

emergency actions may be required. 

Mosquito Monitoring and Management Strategies 

1.14.1. Work cooperatively with the local mosquito and vector control 

districts to monitor and manage pest mosquitoes consistent with 

National Policy, the Complex’s IPM plan, and Compatibility 

Determinations. 

1.14.2. Implement BMP’s (Kwasney et al. 2004) for mosquito 

management on all habitat and water management activities. 

2. Threatened and Endangered Species Goal 

Conserve, manage, restore, and enhance threatened and 

endangered species and their habitats including vernal pool 

plants and invertebrates, and giant garter snakes. 

2.1. Threatened & Endangered Species Objective 

Monitor twelve Federal and State threatened and endangered 

species on 23,973 acres of Refuge lands annually by 2013. 

Rationale: Federally listed threatened, endangered, and candidate 

species are trust responsibilities under the jurisdiction of the Service. 

Threatened and endangered species, as well as those proposed for 

Federal listing, are likely to become extinct due to environmental 

factors. The Refuges will help to achieve goals described in the 

Recovery Plan for Colusa grass, hairy Orcutt grass, Greene’s 

tuctoria, Hoover’s spurge, Conservancy fairy shrimp, vernal pool 

fairy shrimp, vernal pool tadpole shrimp (USFWS 2005a), for 

palmate-bract bird’s-beak (USFWS 1998), and in the Draft Recovery 

Plan for giant garter snake (USFWS 1999a). 

Giant garter snake 

USFWS photo 

Comprehensive Conservation Plan 165 
Chapter 4 

State threatened and endangered species have been identified as 

Birds of Conservation Concern by the Service, and are trust 

responsibilities of the Service under the Migratory Bird Treaty Act. 

Populations are in decline due, in part, to habitat degradation and 

destruction. Their conservation, management, and restoration are 

mandated purposes of the Refuges. Monitoring is necessary to 

determine population distribution, abundance, survival, habitat use, 

and to identify restoration and management needs. This objective 

also helps to achieve Central Valley and Bay-Delta Region 

Conservation Action C in the California Wildlife Action Plan (CDFG 

2005c). 

Threatened &Endangered Species Strategies 

2.1.1. Document Refuge habitat use of Federal and State 

threatened and endangered species (palmate-bracted bird’s-beak, 

hairy Orcutt grass, Greene’s tuctoria, Hoover’s spurge, 

Conservancy fairy shrimp, vernal pool fairy shrimp, vernal pool 

tadpole shrimp, giant garter snake, Swainson’s hawk, greater 

sandhill crane, and western yellow-billed cuckoo) through 

regular, periodic, or specifically coordinated surveys. 

2.1.2. Protect, conserve, maintain, enhance, and where appropriate 

restore habitat for threatened and endangered species. 

2.1.3. Implement giant garter snake avoidance measures, including 

conducting surveys prior to any planned work activities where 

hibernation areas may be disturbed. 

2.1.4. Support recovery activities for species identified in Fish and 

Wildlife Service recovery plans for palmate-bracted bird’s-beak, 

giant garter snake, and vernal pool plant and animal species 

(USFWS 1998, 1999a, 2005). 

2.1.5. Assist with the development and implementation of 

reintroduction and introduction programs to restore extirpated 

populations and protect individual species from the threat of 

extirpation due to random environmental or genetic events 

(USFWS 2005a) for the following: Colusa grass, palmate-bracted 

bird’s-beak, hairy Orcutt grass, Green’s tuctoria, Hoover’s 

spurge, vernal pool saltbush, Ferris’s milk-vetch, Conservancy 

fairy shrimp, vernal pool fairy shrimp, vernal pool tadpole shrimp, 

and other recovery plan species, as appropriate. 

2.1.6. Support management-oriented research, such as the effects of 

various vegetation management techniques for the control of 

invasive plant species or describe soil and water characteristics 

(e.g., profile, texture, duripan, salinity/alkalinity) of speciesspecific reference pools for vernal pool habitat 

restoration/recovery projects. 

166 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

2.1.7. Support research for actions identified in recovery plans that 

promote the recovery of threatened and endangered species such 

as: cooperative range-wide and directed population status and 

habitat condition surveys; seed/cyst collections/banking; genetics 

and demography for conservation and 

reintroduction/introduction; and effects of habitat management 

(USFWS 2005a, 2007a). 

2.1.8. Provide annual and periodic Refuge monitoring survey 

information on listed species to appropriate State (CDFG State 

Office, Habitat Conservation Planning Branch, Region 2 Office) 

and Federal agencies (USFWS–Sacramento Fish and Wildlife 

Office, Permit Coordinator, Endangered Species and Recovery 

branches). 

2.1.9. Support management-oriented research on threatened and 

endangered species. 

2.1.10. Hire one full time and one part time wildlife biologist to 

implement endangered species management. 

3. Visitor Services Goal 

Provide visitors of all ages and abilities with quality wildlifedependent recreation (hunting, wildlife observation, 

photography, environmental education, and interpretation), and 

volunteer opportunities to enhance public appreciation, 

understanding, and enjoyment of fish, wildlife, habitats, and 

cultural resources. 

3.1. Hunting Objective

Implement a high quality hunting program including opportunities 

for approximately 22,000 annual hunting visits on 8,525 acres by 2023,

depending on season length and climatic conditions. 

Rationale: Hunting is identified in the Improvement Act as a priority 

public use that can be allowed when compatible with other Refuge 

purposes. As a result, the Refuges propose to continue hunting of 

waterfowl, coot, common moorhen, snipe, and pheasant. The hunting 

program will be conducted in a safe and cost-effective manner and 

will be carried out consistent with State regulations. The Hunting 

Plan (Appendix C) was developed to provide safe hunting 

opportunities, while minimizing conflicts with other priority wildlifedependent recreational uses. Other visitor uses occur on different 

areas on the Refuges, thereby minimizing potential conflicts with 

hunters (Figures 11-14). The Refuge hunting program complies with 

the Code of Federal Regulations Title 50, 32.1 and is managed in 

accordance with Service Manual 605 FW 2, Hunting. 

Comprehensive Conservation Plan 167 
Figure 11. Sacramento Refuge Visitor Services Map. 

Chapter 4 

168 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Figure 12. Delevan Refuge Visitor Services Map. 

Planned Refuge Management 

Comprehensive Conservation Plan 169 
Figure 13. Colusa Refuge Visitor Services Map. 

Chapter 4 

170 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Figure 14. Sutter Refuge Visitor Services Map. 

Planned Refuge Management 

Comprehensive Conservation Plan 171 
Chapter 4 

Hunting Strategies: 

3.1.1. Implement the Hunt Plan for the Refuges. 

3.1.2. Coordinate hunt program operations with CDFG including 

the annual pre and post hunting meetings. 

3.1.3. Add hunt program changes to CDFG regulations and 50 CFR 

annually. 

3.1.4. Provide the Complex’s hunting brochure at the hunter check 

station, interpretive kiosks, and visitor center. 

3.1.5. Disseminate hunting information packet at the Refuge 

Complex visitor center. 

3.1.6. Provide and update hunting information on the Complex’s 24­

hour telephone information line and on the website. 

3.1.7. Continue to coordinate the Junior and Youth Waterfowl 

Hunts on Sacramento, Delevan, and Colusa Refuges with 

California Waterfowl Association and CDFG. 

3.1.8. Monitor hunting visits and bird harvest every hunt day. 

3.1.9. Work with the Refuge Complex’s Hunting Program Working 

Group to develop and improve the Refuges’ hunting program, 

including access and facilities for hunters with disabilities. 

3.1.10. Work cooperatively with CDFG wardens to enforce State 

Fish and Game hunting laws and Refuge-specific regulations to 

provide a quality experience for all visitors. 

3.1.11. Maintain hunter check stations and kiosks to effectively 

process hunters and provide hunter-related information. 

3.1.12. Convert a portion of the free roam area 

to assigned ponds at Sutter and Colusa 

Refuges and convert some spaced blinds to 

assigned ponds at Sacramento Refuge. 

3.1.13. Consider allowing limited spring turkey 

hunting opportunities on Sacramento, 

Delevan, and Colusa Refuges based on 

sufficient numbers present on the Refuges, 

habitat conditions, and the development of a 

turkey hunt management plan, as well as the 

appropriate National Environmental Policy 

Act compliance. 

Waterfowl hunting on Colusa Refuge 

Photo by Mike Peters 

172 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Wildlife observation 

Photo by Jackie Ferrier 

Planned Refuge Management 

3.1.14. Hire one full-time clerk position to implement the hunting 

program and support other Refuge programs. 

3.2. Wildlife Observation Objective 

Provide quality opportunities for 100,000 wildlife viewing annual 

visits on 8,575 acres by 2023. 

Rationale: Wildlife observation is identified in the Improvement Act 

as a priority public use that can be allowed when compatible with 

other Refuge purposes. As a result, the Refuges encourage first-hand 

opportunities to observe wildlife in their habitats. This activity will be 

managed to ensure that people have opportunities to observe wildlife 

in ways that minimize wildlife disturbance and damage to the 

Refuges’ habitats. Wildlife viewing will be managed to foster a 

connection between visitors and natural resources. The Visitor 

Services Plan (Appendix D) was developed to provide guidance for 

the Refuges’ public use program. The wildlife observation program 

will be managed in accordance with Service Manual 605 FW 4, 

Wildlife Observation. 

Wildlife Observation Strategies: 

3.2.1. Maintain and enhance auto tour routes on Sacramento and 

Colusa Refuges to provide viewing opportunities of wildlife and 

their habitats. 

3.2.2. Expand the hours on all Refuges to one hour before sunrise to 

one hour after sunset. 

3.2.3. Maintain the wildlife viewing facilities on Sacramento, 

Delevan, and Colusa Refuges. 

3.2.4. Upgrade walking trails on Sacramento and Colusa Refuges to 

provide for universal access. 

3.2.5. Construct a walking trail on Sutter Refuge and provide 

Comprehensive Conservation Plan 173 
Chapter 4 

guided tours from April-June. 

3.2.6. Continue to plan and integrate universal access, facilities and 

programs to provide and enhance a quality wildlife observation 

program, including replacement of the wildlife observation blind 

at Colusa Refuge with an accessible blind and boardwalk. 

3.2.7. Open selected portions of the hunt area (2,275 acres) and 

modify parking areas to provide wildlife observation from 

February through June (post waterfowl season) on Sacramento, 

Colusa, and Sutter Refuges. 

3.2.8. Add wildlife viewing platforms along Maxwell Road and Four 

Mile Road on Delevan Refuge. 

3.2.9. Install a remote camera on an eagle nest or a view of the 

Butte Sink WMA to facilitate viewing via the Complex’s website 

and the Refuge Headquarters. 

3.2.10. Increase the Refuge Day and Annual Pass fees. 

3.2.11. Hire a full-time tractor operator and maintenance worker to 

implement the wildlife observation and support other Refuge 

programs. 

3.3. Wildlife Photography Objective 

Provide quality opportunities for 80 photography blind visits and 

10,000 wildlife photography annual visits on 8,758 acres by 2023. 

Rationale: Wildlife photography is identified in the Improvement Act 

as a priority public use that can be allowed when compatible with 

other Refuge purposes. As a result, the Refuges encourage first-hand 

opportunities to observe and photograph wildlife in their habitats. 

This activity will be managed to ensure that people have 

opportunities to photograph wildlife in ways that minimize wildlife 

disturbance and damage to the Refuges’ habitats. Wildlife 

photography will be managed to foster a connection between visitors 

and natural resources. The Visitor Services Plan (Appendix D) was 

developed to provide guidance for the Refuges’ public use program. 

The wildlife photography program will be managed in accordance 

with Service Manual 605 FW 5, Wildlife Photography. 

Wildlife Photography Strategies: 

3.3.1. Maintain and enhance auto tour routes on Sacramento and 

Colusa Refuges to provide photographic opportunities from a 

vehicle. 

3.3.2. Maintain two wildlife photography blinds on Sacramento 

Refuge and one wildlife photography blind on Colusa Refuge. 

174 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Marsh Madness at Sacramento Refuge 

USFWS photo 

Planned Refuge Management 

3.3.3. Construct and maintain a universally accessible photography 

blind on Delevan Refuge. Replace one of the Sacramento Refuge 

wildlife photography blinds with a universally accessible blind. 

3.3.4. Open selected portions of the hunt area (2,275 acres) and 

modify parking areas to provide wildlife photography from 

February through June (post waterfowl season) on Sacramento, 

Colusa, and Sutter Refuges. 

3.3.5. Update photographer guidelines, maps, and photography 

blind reports annually. 

3.3.6. Evaluate photography blind reports and implement changes 

annually. 

3.3.7. Maintain the Complex’s website to provide information about 

current photographer guidelines and facilities. 

3.3.8. Offer photography workshops and guided field trips on 

Sacramento Refuge utilizing the Wetlands Resource Center. 

3.4. Environmental Education Objective 

Develop an environmental education program by 2023 to serve 5,000 

students annually. Develop an environmental education program that 

promotes in-depth studies of the ecological principles that are 

associated with wetland and riparian ecosystems and the Refuges’ 

natural, cultural, and historical resources. The education activities 

will be designed to develop awareness and understanding for refuge 

resources and management activities. 

Rationale: Environmental education is identified in the Improvement 

Act as a priority public use that can be allowed when compatible with 

other Refuge purposes. The Refuges encourage environmental 

education as a process of building knowledge in students. The refuge 

staff will work with schools (K-12) to integrate environmental 

concepts and concerns into structured educational activities. These 

Refuge-lead or educator-conducted activities are intended to actively 

involve students or others in first-hand activities that promote 

Comprehensive Conservation Plan 175 
Chapter 4 

discovery and fact-finding, develop problem-solving skills, and lead to 

personal involvement and action. Refuge staff will promote 

environmental education that: is aligned to the current Federal, State 

and local standards; is curriculum-based that meets the goals of 

school districts adopted instructional standards; and provides 

interdisciplinary opportunities that link the natural world with all 

subject areas. The Visitor Services Plan (Appendix D) was developed 

to provide guidance for the Refuges’ public use program. The 

environmental education program will be managed in accordance 

with Service Manual 605 FW 6 Environmental Education. This 

objective also helps to achieve Statewide Conservation Action J in the 

California Wildlife Action Plan (CDFG 2005c). 

Environmental Education Strategies: 

3.4.1. Construct and operate a Wetlands Resource Center at 

Sacramento Refuge. 

3.4.2. Schedule and plan 100 school group field trips annually 

utilizing the Wetlands Resource Center at Sacramento Refuge 

and the visitor facilities at Colusa Refuge. 

3.4.3. Offer the Discovery Pack containing environmental education 

activities and on-site information for use on walking trails on 

Sacramento and Colusa Refuges. 

3.4.4. Annually assist schools who wish to implement their in-depth 

study of wetlands and riparian habitats on Sacramento Refuge 

utilizing the Wetlands Resource Center. 

3.4.5. Facilitate after school programs involving activities such as 

habitat restoration, wetland analysis, and student mentor 

workshops. 

3.4.6. Develop a partnership with the Girl Scouts: Linking Girls to 

the Land to assist habitat restoration projects. 

3.4.7. Facilitate two annual resource-training workshops (e.g. 

Project Wild or Project Wet) about the Refuges’ environmental 

education program for educators. 

3.4.8. Annually disseminate current environmental education 

program guidelines and activities offered to teachers. 

3.4.9. Maintain the Complex’s website to promote current 

educational opportunities, provide reservation form, and update 

guidelines. 

3.4.10. Update and provide the Environmental Education Guide 

brochure. 

176 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

3.4.11. Utilize interpretive specialists, interns, and volunteers to 

facilitate the environmental education program. 

3.4.12. Hire one full-time interpretive specialist to implement 

environmental education activities and the visitor services 

program. 

3.4.13. Hire one full-time custodian/maintenance worker to maintain 

visitor service facilities. 

3.5. Interpretation Objective 

Refuge staff will develop an interpretive program to provide 20,000 

annual visits. The program will promote public awareness and 

support of the Refuges’ resources and management activities by 2023. 

Rationale: Interpretation is identified in the Improvement Act as a 

priority public use that can be allowed when compatible with other 

Refuge purposes. As a result, the Refuges encourage interpretation 

as both an educational and recreational opportunity that is aimed at 

revealing relationships, examining systems, and exploring how the 

natural world and human activities are interconnected. Participants 

of all ages can voluntarily engage in stimulating and enjoyable 

activities as they learn about the issues confronting fish and wildlife 

resource management on the Refuges. First-hand experiences with 

the environment will be emphasized, although presentations, 

audiovisual media, and exhibits will be necessary components of the 

Refuges’ interpretive program. The Visitor Services Plan (Appendix 

D) was developed to provide guidance for the Refuges’ public use 

program. The interpretive program will be managed in accordance 

with Service Manual 605 FW 7, Interpretation. 

Effective outreach is an important component of the interpretive 

program. The Refuges will provide two-way communication between 

the Refuges and the public to establish a mutual understanding and 

promote involvement with the goal of improving joint stewardship of 

our natural resources. Outreach will be designed to identify and 

understand the issues and target audiences, craft messages, select 

the most effective delivery techniques, and evaluate effectiveness. 

Refuge outreach will follow the guidance of the National Outreach 

Strategy: A Master Plan for Communicating in the U.S. Fish and 

Wildlife Service (USFWS 1997). 

In 2007, the Service declared that “connecting people with nature” is 

among the agencies highest national priorities (USFWS 2008). A 

connection with nature, whether it’s hiking, fishing, camping, hunting, 

or simply playing outside, helps children develop positive attitudes 

and behaviors towards the environment. Positive interactions with 

the environment can lead to a life-long interest in enjoying and 

preserving nature. People’s interest in nature is crucial to the Service 

Comprehensive Conservation Plan 177 
Chapter 4 

mission of conserving, protecting, and enhancing fish, wildlife, plants, 

and their habitats. 

Interpretation Strategies: 

3.5.1. Use the Complex’s visitor center to provide presentations and 

exhibits. 

3.5.2. Maintain interpretive kiosks, walking trails, auto tour routes, 

the visitor center, and Wetlands Resource Center for use by 

refuge visitors. 

3.5.3. Lead at least 20 tour groups on the Refuges annually. 

3.5.4. Develop “Sense of Wonder Zones” or naturalized play areas 

for family-oriented activities on the Sacramento and Colusa 

Refuges where people of all ages can reconnect with nature. 

3.5.5. Create interpretive geocaching opportunities on the 

Sacramento and Colusa Refuges where people of all ages can 

increase their awareness of fish and wildlife resources and 

outdoor activities that the Refuges provide. 

3.5.6. Continue to participate in or provide information to local 

annual events (e.g. International Migratory Bird Day, National 

Wildlife Refuge Week, Snow Goose Festival, Pacific Flyway 

Decoy Association Wildlife Art Festival, California State Fair, 

International Sportsman’s Expo, and Return of the Salmon 

Festival). 

3.5.7. Participate in fire prevention education and outreach about 

the role of fire and its management uses. 

3.5.8. Write news releases for local and State newspapers and 

articles for magazines. Conduct television and radio interviews 

upon request. 

3.5.9. Maintain the Complex’s website. 

3.5.10. Maintain the Sacramento Refuge radio station (FM 93.1). 

3.5.11. Provide interpretive brochures at kiosks and in the visitor 

center. 

3.5.12. Maintain and upgrade the Discovery Room displays, videos, 

and activities. 

3.5.13. Manage and stock the bookstore to provide relevant books 

and miscellaneous items that relate to the Complex. 

3.5.14. Continue to coordinate and facilitate the California Junior 

178 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Junior Duck Stamp Display at Snow Goose Festival 

Photo by Jackie Ferrier 

Planned Refuge Management 

Duck Stamp Contest and judging. 

3.5.15. Continue to host and facilitate California Waterfowl 

Association’s (CWA) Marsh Madness school events. 

3.5.16. Utilize interpretive specialists, interns, and volunteers to 

coordinate annual events on and off Refuge, manage the 

bookstore, and coordinate the California Junior Duck Stamp 

Program. 

3.5.17. Utilize interns to assist with Refuge programs (e.g. managing 

the visitor center on weekends, facilitating school groups). 

3.6. Volunteer Objective 

Increase the number of volunteers to 120 in order to support a 

variety of Refuge programs by 2023. 

Rationale: The National Wildlife Refuge System Volunteer and 

Partnership Enhancement Act of 1998 (P.L. 105-242) strengthens the 

Refuge System’s role in developing relationships with volunteers. 

Volunteers possess knowledge, skills, and abilities that can enhance 

the scope of refuge operations. Volunteers enrich refuge staff with 

their gift of time, skills, and energy. Refuge staff will initiate, 

support, and nurture relationships with volunteers so that they may 

continue to be an integral part of Refuge programs and management. 

The volunteer program will be managed in accordance with the Fish 

and Wildlife Service Manual, Part 150, Chapters 1-3, “Volunteer 

Services Program”, and Part 240 Chapter 9 “Occupational Safety and 

Health, Volunteer and Youth Program”. 

Currently the Complex volunteer program consists of 69 individuals 

who assist with wildlife-dependent recreation, maintenance, wildlife 

Comprehensive Conservation Plan 179 
Chapter 4 

and habitat management, environmental education, and cultural 

resource programs. 

Volunteer Strategies: 

3.6.1. Utilize interpretative specialists and interns to coordinate the 

volunteer program. 

3.6.2. Recruit interns through the California Waterfowl Association, 

California State University Chico (CSU/Chico) internship 

program, and other universities. 

3.6.3. Recruit a variety of community groups and individuals (e.g. 

CSU/Chico, Butte College, Boy Scouts, Girl Scouts, Altacal 

Audubon Society). 

3.6.4. Host an annual volunteer recognition dinner. 

3.6.5. Facilitate volunteer training workshops. 

3.6.6. Host an annual work day (Brush Up Day) to clean up 

Refuges’ hunt areas. 

3.6.7. Utilize the Girl Scout Council to recruit volunteers. 

3.6.8. Provide Service volunteer uniforms for all volunteers to wear 

when greeting the public or at special events. 

American wigeon 

Photo by Steve Emmons 

180 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

4. Partnerships Goal 

Promote partnerships to preserve, restore, and enhance a 

diverse, healthy, and productive ecosystem in which the 

Refuges play a key role. 

4.1. Partnership Objective 

Maintain and enhance at least 25 partnerships among Federal, State, 

local agencies, organizations, schools, corporations, and private 

landowners to promote the understanding and conservation of the 

Refuges’ resources, activities, and management by 2023. 

Rationale: The Service recognizes that strong citizen support 

benefits the Refuge System. These benefits include the involvement 

and insight of citizen groups in the Refuges’ resource and 

management issues and decisions, a process that helps managers gain 

an understanding of public concerns. Partners support Refuge 

activities and programs, raise funds for projects, are advocates on 

behalf of wildlife and the Refuge System, and provide support on 

important wildlife and natural resource issues. In “Fulfilling the 

Promise” (USFWS 1999c), the Service identified the need to forge 

new and non-traditional alliances and strengthen existing 

partnerships with States, Tribes, non-profit organizations and 

academia to broaden citizen and community understanding and 

support for the National Wildlife Refuge System. This objective also 

helps to achieve Central Valley and Bay-Delta Region Conservation 

Actions B and L in the California Wildlife Action Plan (CDFG 2005c). 

A variety of people including, but not limited to, scientists, farmers, 

birders, hunters, photographers, and students have a great deal of 

interest in the Complex’s management, fish and wildlife species, and 

habitats. New partnerships will be formed as opportunities, funding, 

and staff are available. 

Partnership Strategies: 

4.1.1. Maintain good relations and open communication with 

partners. 

4.1.2. Actively look for partnering opportunities with local and 

regional conservation groups, academic institutions, 

organizations, and other local, State and Federal agencies. 

4.1.3. Pursue opportunities to cost-share mutually beneficial 

projects with other organizations. 

4.1.4. Expand opportunities with local Chambers of Commerce to 

participate in local events and improve dissemination of public 

recreation literature about the Refuges. 

4.1.5. Stay actively involved in Federal, State, and local planning 

Comprehensive Conservation Plan 181 
Chapter 4 

processes to protect the Refuges’ resources and foster 

cooperative management of those resources. 

4.1.6. Work closely with Bureau of Reclamation and local irrigation 

district personnel on water delivery issues. 

4.1.7. Continue to participate in the Sacramento Valley Water 

Quality Coalition. 

4.1.8. Continue partnership with Altacal Audubon Society to 

operate the bookstore at Sacramento Refuge. 

4.1.9. Maintain active participation with the Central Valley Joint 

Venture. 

4.1.10. Maintain cooperative agreement with U.S. Geological Survey 

to conduct management-oriented research and monitoring 

efforts. 

4.1.11. Continue partnerships with California Waterfowl Association, 

Ducks Unlimited, and other conservation non-governmental 

organizations. 

4.2. Cooperation with Adjacent Landowners Objective 

By 2023, create 10 opportunities for new and maintain existing 

partnerships with private landowners to promote cooperation and 

address mutual concerns. 

Rationale: It is important to communicate with our neighbors to help 

identify any issues at an early stage and attempt to resolve any 

conflicts that may exist. 

Private Landowner Cooperation Strategies: 

4.2.1. Maintain contact with adjacent neighbors to discuss mutual 

concerns and opportunities. 

4.2.2. Implement improvements and operational revisions to resolve 

issues with adjacent landowners that are compatible with the 

mission of the Service and purpose of the Refuges, as well as 

consistent with the funding available to the Refuges. 

4.2.3. Design habitat restoration projects to address considerations 

of adjoining landowners, including but not limited to: 

 Provision of access controls and access for emergency and 

utility services. 

 Consideration of appropriate fire access and breaks. 

182 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

 Consideration of appropriate buffers where new planting 

directly adjoins agricultural crops. 

 Use of natural predation control strategies. 

4.2.4. Continue to consult with adjoining landowners as part of the 

development of plans for proposed restoration projects and other 

physical changes to the Refuges. 

4.2.5. Commission field surveys as needed to identify specific 

property boundaries where uncertainty has contributed to 

substantive violations of Refuge regulations. 

4.2.6. Annually host a habitat management workshop for private 

landowners. 

5. Resource Protection Goal 

Adequately protect and maintain all natural and cultural 

resources, staff and visitors, equipment, facilities, and other 

property on the Refuges. 

5.1. Law Enforcement Objective

Provide a safe environment for visitors, protect the Refuges’ 

resources, and ensure compliance with regulations through effective 

law enforcement on each Refuge by 2008. 

Rationale: An increasing number of Refuge facilities and visitors 

necessitate an adequate level of safety and security through an 

enhanced law enforcement presence. Illegal activities, such as drug 

cultivation, poaching, vandalism, and vehicle stripping, are present on 

Refuge lands where there are public activities. Strict law 

enforcement and the support of partners are necessary to provide a 

safe environment for visitors and staff. In addition, a common belief 

among neighboring landowners is that public ownership, easements, 

or access could result in increased vandalism and theft of agricultural 

equipment, poaching, and disregard of private property rights. A 

well-planned and coordinated program will be necessary to 

successfully address these concerns. This objective also helps to 

achieve Central Valley and Bay-Delta Region Conservation Action Q 

in the California Wildlife Action Plan (CDFG 2005c). 

Law Enforcement Strategies 

5.1.1. Develop Memorandum of Understandings (MOUs) with 

various law enforcement agencies to improve coordination, 

improve safety, and coordinate efforts in areas of special concern. 

Comprehensive Conservation Plan 183 
Chapter 4 

5.1.2. Provide public education and signage as part of law 

enforcement programs and provide a sufficient level of law 

enforcement from various agencies to address these issues. 

5.1.3. Employ three full-time park rangers (refuge law enforcement 

officers), one full-time supervisory law enforcement officer, and 

supplement their duty schedule with dual-function officers. 

5.1.4. Maintain a daily law enforcement presence to ensure that 

violations are deterred or successfully detected, investigated, and 

the violators are apprehended, charged, and prosecuted. 

5.1.5. Have refuge officers work closely with CDFG game wardens 

and deputy sheriffs from Glenn, Colusa, and Sutter counties. 

5.1.6. Develop a Law Enforcement Plan for the Complex. 

5.1.7. Annually maintain boundary, closed area, and other public 

use signs. 

5.2. Safety Objective 

By 2008, provide Refuge facilities and lands that are safe for public 

use and management activities through annual inspections and 

routine maintenance. 

Rationale: Visitor and staff safety is a high priority for the Refuges. 

It is extremely important to have comprehensive safety strategies. 

The Refuges are committed to training staff in the most current 

safety standards and practices, maintaining facilities, coordinating 

with law enforcement partners, and providing an effective monitoring 

program to provide the safest environment possible. 

Northern harrier 

Photo by Steve Emmons 

Safety Strategies: 

5.2.1. Administer and monitor required permits, licenses, and 

inspections on a repetitive basis under the Federal Facility 

Compliance Act and Service policy. 

184 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Planned Refuge Management 

5.2.2. Promptly replace, upgrade, or temporarily close any facility 

that comprises a public safety hazard. 

5.2.3. Minimize injuries to staff and visitors through preventive 

measures and be prepared to respond to injuries if they occur. 

5.2.4. Ensure that safety procedures, designated personnel, and 

equipment and supplies (e.g., first aid kits and fire extinguishers) 

are in place and kept current. 

5.2.5. Conduct monthly staff safety meetings covering pertinent 

topics, quarterly safety committee meetings, and annual safety 

inspections to ensure that Refuge facilities and lands are safe for 

public and staff use. 

5.2.6. Train and refresh staff in CPR and basic first aid. 

5.2.7. Maintain existing access roads and parking areas by grading, 

mowing, and replacing culverts, as needed, for public vehicle 

access, law enforcement, and habitat management activities. 

5.2.8. Maintain secondary roads and pathways for public pedestrian 

traffic by grading, mowing and replacing culverts, as needed. 

5.2.9. Help protect refuge visitors, neighbors, and employees 

through fire prevention, hazard reduction, and fire trespass 

programs. 

5.2.10. Maintain a current knowledge and status of local wildlife 

diseases that are potentially transmitted to humans, and manage 

visitation accordingly. Provide timely information to the public. 

5.2.11. Continue to prohibit the use or possession of alcoholic 

beverages while hunting (50 CFR 32.2j). In addition, prohibit the 

consumption or possession of an open container of alcohol within 

public areas on the Refuges. 

5.3. Facility Maintenance Objective 

By 2023, perform and document preventive and corrective 

maintenance on 100 percent of the buildings, structures, and access 

routes, including facilities with historic significance. 

Rationale: Maintenance of buildings, structures, and access routes is 

critical to meeting Refuge administrative needs and resource goals. 

Facility Maintenance Strategies: 

5.3.1. Maintain existing offices, shops, and check stations. 

5.3.2. Maintain historic buildings and structures. 

Comprehensive Conservation Plan 185 
Chapter 4 

5.3.3. Maintain roads, levees, fences, gates, water conveyance 

system, and other Real Property to Service standards. 

5.3.4. Hire a facility management coordinator to operate and 

maintain the Service Asset Maintenance Management System 

and Real Property databases. 

Black-tailed jackrabbit 

Photo by Steve Emmons 

186 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Plan Implementation 

Chapter 5. Management Plan 

Implementation 

1. Implementation 

The CCP will serve as the primary management reference document 

for Refuge planning, operations, and management for the next 15 

years or until it is formally revised or amended within that period. 

The Service will implement the final CCP with assistance from 

existing and new partner agencies and organizations and from the 

public. The timing and achievement of the management strategies 

proposed in this document are contingent upon a variety of factors, 

including: 

 Funding & Staffing 

 Completion of Step-Down Plans 

 Compatibility Determinations 

 Compliance Requirements 

 Adaptive Management 

 Monitoring 

Each of these factors is briefly discussed as it applies to the CCP. 

CCPs provide long-term guidance for management decisions and set 

forth goals, objectives, and strategies needed to accomplish refuge 

purposes and identify the Service’s best estimate of future needs. 

These plans detail program planning levels that are sometimes 

substantially above current budget allocations and, as such, are 

primarily for Service strategic planning and program prioritization 

purposes. Accordingly, the plans do not constitute a commitment for 

staffing increases, operational and maintenance increases, or funding 

for future land acquisition. 

2. Funding & Staffing 

Resources are required to adequately operate any national wildlife 

refuge including initial capital outlay for equipment, facilities, labor 

and other expenses as well as recurring expenses (Table 21). The 

estimated initial capital outlay to implement the strategies described 

in this CCP is approximately $19 million. Not all of these capital 

expenditures would occur in the same year as many of these expenses 

would be most likely implemented over the next fifteen years if 

approval and funding is provided by Congress. The detailed 

descriptions of the objectives and their associated implementation 

strategies serve as a guide to the ideal time frame in which to 

implement capital expenditures. The largest costs for initial outlays 

are for visitor services and habitat restoration. 

Comprehensive Conservation Plan 187 
Table 21. Estimated Initial Capital Outlay to Fully Implement the CCP. 

Expenditure [Related Objective(s)] Unit Cost Unit Quantity Total Cost 

Construct Wetland Resource Center 

(Sac) [Objectives 3.4, 3.5] 

$5,984,000 ea 1.0 $5,984,000

Obtain equipment and supplies for 

Wetland Resource Center (Sac) 

[Objectives 3.4, 3.5] 

$184,800 ea 1.0 $184,800 

Improve entrance road and visitor 

parking area including railroad 

crossing device (Sac) [Objective 5.2] 

$540,000 ea 1.0 $540,000 

Construct accessible restroom (Sac) 

[Objectives 3.2, 3.3, 3.4, 3.5] 

$227,000 ea 1.0 $227,000

Replace deteriorated domestic water 

well and water lines at headquarters 

(Sac) [Objectives 5.2, 5.3] 

$190,000 ea 1.0 $190,000 

Repair visitor entrance road and 

parking areas (Sac) [ Objectives 3.2, 

3.4, 3.5, 5.3] 

$60,800 ea 1.0 $60,800 

Improve Maxwell Road Parking area 

including viewing platform (Del) 

[Objectives 3.2, 3.5] 

$102,200 ea 1.0 $102,200

Obtain Wayside Exhibit materials for 

viewing platform (Del) [Objectives 3.2, 

3.5] 

$94,600 ea 1.0 $94,600 

Construct parking area and viewing 

platform along 4-Mile Road (Del) 

[Objectives 3.2, 3.3, 3.5] 

$80,000 ea 1.0 $80,000 

Construct universally accessible 

photography blind including boardwalk 

(Sac) [Objective 3.3] 

$33,100 ea 1.0 $33,100

Construct universally accessible 

photography blind including boardwalk 

(Del) [Objective 3.3] 

$18,000 ea 1.0 $18,000 

Modifications in hunt areas for springsummer use (e.g. signs, additional 

kiosks, parking lot modifications, etc.) 

(Sac, Col and Sut) [Objectives 3.2, 3.3] 

$10,000 ea 3.0 $30,000

Renovate existing trails for universal 

access (Sac) [Objectives 3.2, 3.3, 3.4, 

3.5] 

$116,000 ea 1.0 $116,000 

Renovate existing trail for universal 

access (Col) [Objectives 3.2, 3.3] 

$75,000 ea 1.0 $75,000

Replace wildlife observation blind with 

an accessible blind and board walk 

(Col) [Objectives 3.2, 3.3] 

$75,000 ea 1.0 $75,000

Install electric line for hunter check 

station (Del) [Objectives 3.1, 5.2] 

$172,000 ea 1.0 $172,000 

Replace hunter access bridges with 

culverts (Sac and Del) [Objectives 3.1, 

5.2, 5.3] 

$10,000 ea 2.0 $20,000

Chapter 5 

188 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

Plan Implementation 

Restore Tract 26 to grassland / 

wetland mix (Col) [Objective 1.2] 

$50,000 ea 1.0 $50,000 

Replace maintenance shop (Sac) 

[Objectives 5.2, 5.3] 

$1,400,000 ea 1.0 $1,400,000 

Construct fire cache and vehicle 

storage building (Sac) [Objectives 5.2, 

5.3] 

$470,000 ea 1.0 $470,000 

Widen and improve 26.2 delivery canal 

(Sac) [Objectives 1.1, 5.3] 

$2,511,000 ea 1.0 $2,511,000 

Replace deteriorated water control 

structures (all) [Objectives 1.1, 5.3] 

$1,501,000 ea 1.0 $1,501,000 

Install sprinkler fire-protection and 

burglar alarm systems in headquarter 

office (Sac) [Objective 5.2] 

$86,000 ea 1.0 $86,000 

Renovate Necropsy Building (Sac) 

[Objective 5.3] 

$160,000 ea 1.0 $160,000 

Construct equipment storage buildings 

(Col and Sut) [Objectives 1.1, 3.1, 5.3] 

$86,000 ea 2.0 $172,000 

Repair service roads (Sac) [Objectives 

1.1, 5.3] 

$18,000 mi 2.0 $36,000 

Repair eroded levees in wetland units 

(Del) [Objectives 1.1, 5.3] 

$26,400 mi 5.0 $132,000 

Purchase disking tractor (Complex) 

[Objectives 1.1, 1.3, 1.13, 3.1, 3.2, 5.3] 

$115,000 ea 1.0 $115,000 

Purchase pull scraper (Sut) [1.1, 5.3] $33,000 ea 1.0 $33,000 

Replace existing heavy equipment 

backlog (Complex) [Objectives 1.1, 3.1, 

5.3] 

$4,268,000 ea 1.0 $4,268,000 

Total $18,936,500 

Annual contracts or cooperative agreements will be needed to provide 

specialized services beyond the core Refuge functions for which staff 

are required. The recurring CCP implementation total approximately 

$3.4 million (Table 22). 

Figures 15 and 16 show the Complex’s organization charts with both 

current and new positions identified. If all positions indicated in Table 

22 and Figures 15 and 16 are filled, the Refuges would be able to 

carry out all aspects of this plan to a reasonable standard. If some 

positions are not filled, all aspects of the Plan would not be completed 

or those projects may be done over a longer period of time. 

Comprehensive Conservation Plan 189 
Chapter 5 

Table 22. Estimated Annual Cost to Fully Implement the CCP1 . 

Expenditure Unit Cost2 Unit Quantity Total Cost Phase3 

Salaries and Benefits 

Refuge Manager - GS14 131,295 FTE 0.6 78,777 

Deputy Refuge Manager - GS13 111,111 FTE 0.8 88,889 

Asst. Refuge Manager (Sac/Del) – GS12 93,436 FTE 1.0 93,436 

Asst. Refuge Manager (Col/Sut) – GS12 93,426 FTE 1.0 93,426 

Natural Resources Planner - GS12 93,436 FTE 0.3 28,030 

Outdoor Recreation Planner - GS12 93,436 FTE 0.6 56,062 

Interpretive Specialist - GS9 64,430 FTE 0.8 51,544 

Interpretive Specialist – GS9 

[Objectives 3.4 and 3.1, 3.2, 3.3, 3.5] 

64,430 FTE 0.8 51,544 1 

Law Enforcement Officer – GS9 74,343 FTE 0.5 37,172 

Law Enforcement Officer – GS7/9 74,343 FTE 0.5 37,172 

Law Enforcement Officer – GS7/9 

[Objective 5.1] 

74,343 FTE 0.5 37,172 3 

Supv. Law Enforcement Officer – GS11 

[Objective 5.1] 

89,951 FTE 0.5 44,976 1 

Supv. Wildlife Biologist - GS12 93,436 FTE 0.6 56,062 

Wildlife Biologist (Sac/Del) - GS11 77,957 FTE 1.0 77,957 

Wildlife Biologist (Col/Sut) - GS9 64,430 FTE 1.0 64,430 

Wildlife Biologist – GS9 

[Objectives 1.1 and 1.2-1.4, 1.6-1.11, 2.1] 

64,430 FTE 1.0 64,430 2 

Wildlife Biologist – GS12 93,436 FTE 0.2 18,687 

Wildlife Biologist - GS5 [Objective 2.1] 42,523 FTE 1.0 42,523 2 

Wildlife Biologist - GS5 [Objective 2.1] 42,523 FTE 1.0 42,523 3 

Wildlife Biologist - GS5 [Objective 1.12] 42,523 FTE 1.0 42,523 2 

Computer Specialist - GS11 

[Objective 1.1 and Goals 1, 2, 3, 4, 5] 

77,957 FTE 0.5 38,979 3 

Facility Management Coord. – GS11 

[Objective 5.3 and Goals 1, 2, 3, 4, 5] 

77,957 FTE 0.5 38,979 1 

Administrative Officer - GS9/11 77,957 FTE 0.6 46,774 

Budget Technician – GS6 47,400 FTE 0.6 28,440 

Budget Technician – GS6 47,400 FTE 0.6 28,440 

Purchasing Agent – GS5 

[Objective 1.1 and Goals 1, 2, 3, 4, 5] 

42,523 FTE 0.6 25,514 3 

Office Automation Clerk - GS4/5 42,523 FTE 0.6 25,514 

Office Automation Clerk – GS5 

[Objective 1.1 and Goals 1, 2, 3, 4, 5] 

42,523 FTE 0.6 25,514 1 

Office Automation Clerk – GS5 

[Objective 3.1 and Goals 1, 2, 3, 4, 5] 

42,523 FTE 0.6 25,514 2 

Eng. Equip. Oper. Leader (Sac/Del) - WL10 78,254 FTE 1.0 78,254 

Eng. Equip. Oper. (Sac/Del) - WG10 71,143 FTE 1.0 71,143 

Eng. Equip. Oper. (Sac/Del) - WG10 

[Objectives 1.1 and 1.2, 1.3, 1.4, 3.1, 3.2, 5.2, 5.3] 

71,143 FTE 1.0 71,143 1 

Eng. Equip. Oper. (Sac/Del) - WG8 

[Objectives 1.1 and 1.2, 1.3, 1.4, 3.1, 3.2, 5.2, 5.3] 

62,895 FTE 1.0 62,895 2 

190 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Plan Implementation 

Eng. Equip. Oper. (Sac) - WG9 67,059 FTE 1.0 67,059 

Eng. Equip. Oper. (Del) - WG9 67,059 FTE 1.0 67,059 

Maint. Mechanic (Sac/Del) - WG9 67,059 FTE 1.0 67,059 

Tractor Operator (Sac) - WG6 

[Objectives 1.1 and 1.2, 1.3, 1.4, 3.1, 3.2, 5.2, 5.3] 

54,431 FTE 1.0 54,431 3 

Tractor Operator (Del) - WG6 

[Objectives 3.2 and 1.2, 1.3, 1.4, 3.1, 3.2, 5.2, 5.3] 

54,431 FTE 1.0 54,431 2 

Maint. Worker (Sac) - WG3 

[Objectives 3.4 and 1.2, 1.3, 1.4, 3.1, 3.2, 5.2, 5.3] 

42,209 FTE 1.0 42,209 2 

Eng. Equip. Oper. (Col) - WG9 67,059 FTE 1.0 67,059 

Maint. Worker (Col/Sut) - WG8 62,895 FTE 1.0 62,895 

Eng. Equip. Oper. (Sut) - WG9 67,059 FTE 1.0 67,059 

Maintenance Worker (Sut) – WG8 

[Objectives 3.2 and 1.2, 1.3, 1.4, 3.1, 3.2, 5.2, 5.3] 

62,895 FTE 1.0 62,895 1 

Fire Management Officer - GS12 107,811 FTE 0.5 53,906 

Asst. Fire Management Officer - GS11 89,951 FTE 0.5 44,976 

Prescribed Fire Specialist - GS9 

[Objectives 1.1 and 1.2, 1.3, 1.4, 3.1, 3.2, 5.2, 5.3] 

74,343 FTE 0.5 37,172 3 

Fire Budget Technician – GS5/6 

[Objectives 1.1 and 1.2, 1.3, 1.4, 3.1, 3.2, 5.2, 5.3] 

47,400 FTE 0.5 23,700 1 

Supv. Range Tech. (Fire) - GS8 67,313 FTE 0.5 33,657 

Supv. Range Tech. (Fire) - GS8 67,313 FTE 0.5 33,657 

Lead Range Tech (Fire) - GS6 54,693 FTE 0.5 27,347 

Lead Range Tech (Fire) - GS6 54,693 FTE 0.5 27,347 

Range Technician (Fire) - GS5 49,065 FTE 0.5 24,533 

Range Technician (Fire) - GS5 49,065 FTE 0.5 24,533 

Fire Crew (seasonal) - GS4 43,853 FTE 0.5 21,927 

Fire Crew (seasonal) - GS4 43,853 FTE 0.5 21,927 

Fire Crew (seasonal) - GS4 43,853 FTE 0.5 21,927 

Fire Crew (seasonal) - GS4 43,853 FTE 0.5 21,927 

Maintenance $200,000 ea 1.0 $200,000 

Invasive Weed Program $80,000 ea 1.0 $80,000 

Water/Pumping Costs $25,000 ea 1.0 $25,000 

Water Quality Monitoring $164,000 ea 1.0 $164,000 

Travel/Training $24,000 ea 1.0 $24,000 

Supplies $100,000 ea 1.0 $100,000 

Printing $20,000 ea 1.0 $20,000 

Custodial Services $1,598 ea 12.0 $19,176 

Wastewater Treatment Plant Operation $1,530 mo 12.0 $18,360 

Grand Total: $4,426,779 $3,355,666 

Shading indicates position identified in the CCP. 

1 Staffing and funding would be sought over the 15 year life of this plan subject to approval and funding by 

Congress. 

2

Unit Cost based on 2007 Grade level/Step 5 with 50 percent benefits for law enforcement and fire and 30 percent 

benefits for everyone else. 

3 Phase indicates a tiering or current priority ranking system that identifies which positions would be hired first 

when given approval and funding from Congress. 

Comprehensive Conservation Plan 191 
Chapter 5 

Figure 15. Sacramento Refuge Complex Staffing Plan. 

192 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Plan Implementation 

Figure 16. Fire Staffing Plan. 

Comprehensive Conservation Plan 193 
Chapter 5 

3. Step-Down Management Plan Summaries 

Some projects or types of projects require more in-depth planning 

than the CCP process is designed to provide; for these projects, the 

Service prepares step-down management plans. In essence, stepdown management plans provide the additional planning details 

necessary to implement management strategies identified in a CCP. 

Included in this document are eight step-down management plans. 

The CCP also proposes two new step down plans including a Law 

Enforcement Plan and a Pest Control Plan. These Plans will be 

completed by 2013. 

3.1. Hunt Plan 

The purpose of the Hunting Plan (Appendix C) is to establish 

guidelines for hunting on the Sacramento, Delevan, Colusa, and 

Sutter Refuges that will provide the public with a quality wildlifedependent recreational experience, an opportunity to use a renewable 

resource, and the ability to maintain wildlife numbers at levels 

compatible with Refuge habitat. It was developed to provide safe 

hunting opportunities, while minimizing conflicts with other priority 

wildlife-dependent recreational uses. The plan will allow the hunting 

program to be conducted in a cost-effective manner, coordinated with 

the State. The hunting program will be reviewed annually by refuge 

staff during the Habitat Management Plan review conducted each 

spring. The activities within the Hunt Plan are evaluated within a 

hunting compatibility determination located in Appendix B. 

3.2. Visitor Services Plan 

The purpose of the Visitor Services Plan (Appendix D) is to establish 

guidelines for public uses on the Sacramento, Delevan, Colusa, and 

Sutter Refuges that will provide the public with a quality wildlifedependent recreational experience. It was developed to provide safe 

wildlife-dependent recreation opportunities, while minimizing 

adverse impacts to the wildlife resources. The plan will allow the 

visitor services program to be conducted in a cost-effective manner. 

The program will be reviewed annually by refuge staff during the 

Habitat Management Plan review conducted each spring. The 

activities within the Visitor Services Plan are evaluated within 

compatibility determinations (hunting, wildlife observation and 

photography, environmental education and interpretation, and 

bicycling) located in Appendix B. 

194 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Plan Implementation 

3.3. Habitat Management Plan 

Refuge staff has developed annual Habitat Management Plans for 

Sacramento, Delevan, Colusa, and Sutter Refuges, which guide the 

refuge manager in the decision making process (Appendix E). Each 

unit is visited annually by a team of managers, biologists, recreation 

planners, and maintenance workers to identify resource issues, 

develop a prioritized list of projects to address those issues, and 

monitor outcomes/responses. The database for this planning 

document is annually updated. The plan is based on an adaptive 

management philosophy that allows the team to assess habitat 

condition and wildlife use of the units annually and make adjustments 

accordingly in order to meet the Refuges’ goals and objectives. 

California goldfields and Hoover’s downingia 

Photo by Joe Silveira 

3.4. Integrated Pest Management Plan 

The Complex has developed an Integrated Pest Management (IPM) 

Plan (Appendix F) to address/reduce public nuisance and human 

health risk from mosquito-transmitted diseases, as well as to address 

invasive and exotic plants on the Refuges. The purposes of this plan 

are: to identify mosquito control methods and materials currently 

approved for use on the Complex; identify use in an IPM program 

that is consistent with the goals of the Complex and minimizes public 

health risk from Refuge-harbored mosquitoes; and provide long-term 

planning to meet the Service’s goal of reducing effects of pesticide 

use on DOI trust resources to the greatest extent possible. This plan 

will be reviewed and updated to include new information and policy 

changes as needed. It covers chemical herbicide/pesticide use (aerial 

and ground application), mechanical eradication, and biological 

controls. Mosquito monitoring and control activities are evaluated 

within a compatibility determination located in Appendix B 

3.5. Resource Inventory and Monitoring Plan 

The purpose of the Wildlife Inventory and Monitoring Plan 

(Appendix G) is to establish guidelines and a schedule for conducting 

routine surveys to inventory and monitor wildlife and plant 

Comprehensive Conservation Plan 195 
Chapter 5 

populations on the Refuges. It was developed to maintain consistency 

in the timing and methods used to collect population and habitat data 

between years. 

3.6. Waterfowl Disease Contingency Plan 

The purpose of the Waterfowl Disease Contingency Plan (Appendix 

H) is to establish protocols for monitoring and responding to wildlife 

disease outbreaks on the Refuges. It was developed to ensure a safe 

working environment for personnel involved in associated disease 

monitoring and clean-up activities while minimizing wildlife losses. 

3.7. Water Management Plan 

Annual Water Management Plans (Appendix I) are prepared for 

Sacramento, Delevan, and Colusa Refuges. The development of these 

plans is a requirement of the Central Valley Project Improvement 

Act (CVPIA), which requires the Bureau of Reclamation to purchase 

and deliver water to these Refuges. The plan outlines water 

management goals and objectives and inventories existing facilities, 

water quality monitoring, water inventory, and best management 

practices. 

3.8. Fire Management Plan 

The Department of the Interior (DOI) fire management policy 

requires that all refuges with vegetation that can sustain fire must 

have a Fire Management Plan (FMP) (Appendix J) that details fire 

management guidelines for operational procedures and values to be 

protected or enhanced. The FMP for the Sacramento, Delevan, 

Colusa, and Sutter Refuges provides guidance on preparedness, 

prescribed fire, wildland fire, and prevention. Values to be considered 

in the FMP include protection of Refuge resources and neighboring 

private properties, effects of burning on Refuge habitats/biota, and 

firefighter safety. Refuge resources include properties, structures, 

cultural resources, trust species (including endangered, threatened, 

and species of special concern), and their associated habitats. The 

FMP will be reviewed periodically to ensure that the fire program is 

conducted in accordance with the Service’s mission and the Refuges’ 

purposes, goals, and objectives. 

This plan is written to provide guidelines for appropriate suppression 

and prescribed fire programs at Sacramento, Delevan, Colusa, and 

Sutter Refuges. Prescribed fires may be used to reduce hazard fuels, 

restore the natural processes and vitality of ecosystems, improve 

wildlife habitat, remove or reduce non-native species, and/or conduct 

research. This plan will help achieve resource management objectives 

by enabling the Refuge to use prescribed fire, as one of several tools, 

to control non-native vegetation, and reduce fire hazards in grassland 

and riparian habitats. It will be used in conjunction with other 

management tools that are currently applied on Refuge properties 

(i.e., grazing, mowing and herbicide applications) to meet resource 

objectives. 

196 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Plan Implementation 

4. Appropriate Use Requirements 

The Appropriate Use policy describes the initial decision process the 

refuge manager follows when first considering whether or not to 

allow a proposed use on a refuge. The refuge manager must find a 

use is appropriate before undertaking a compatibility review of the 

use. Uses that have been administratively determined to be 

appropriate are the six wildlife-dependent recreational uses (hunting, 

fishing, wildlife observation and photography, environmental 

education, and interpretation) and the take of fish and wildlife under 

State regulations. 

A review of appropriateness of existing and proposed Refuge uses 

was completed for the Refuges. Bicycling, commercial photography, 

plant material gathering, grazing, mosquito control, research, and 

walking were found to be appropriate uses on the Refuges. Camping, 

field dog trials, horseback riding, memorials, oil and gas exploration, 

and weddings were found to be not appropriate uses on the Refuges. 

Western kingbird 

Photo by Mike Peters 

5. Compatibility Determinations 

Federal law and policy provide the direction and planning framework 

to protect the Refuge System from incompatible or harmful human 

activities and to insure that Americans can enjoy Refuge System 

lands and waters. The Improvement Act is the key legislation on 

managing public uses and compatibility. 

Before activities or uses are allowed on a refuge, uses must be found 

to be “compatible” through a written compatibility determination. A 

compatible use is defined as a proposed or existing wildlife-dependent 

recreational use or any other use of a national wildlife refuge that, 

based on sound professional judgment, will not materially interfere 

with or detract from the fulfillment of the Refuge System mission or 

the purposes of the national wildlife refuge. Sound professional 

judgment is defined as a decision that is consistent with the principles 

of the fish and wildlife management and administration, available 

science and resources, and adherence to the requirements of the 

Comprehensive Conservation Plan 197 
Chapter 5 

Improvement Act, and other applicable laws. Wildlife-dependent 

recreational uses may be authorized on a refuge when they are 

compatible and not inconsistent with public safety. 

Compatibility determinations for hunting, wildlife observation, 

photography, commercial photography, environmental education, 

interpretation, bicycling, grazing, plant material gathering, and 

mosquito and other vector control are included in Appendix B. These 

uses were all found to be compatible. 

6. Compliance Requirements 

This CCP was developed to comply with all Federal laws, executive 

orders, and legislative acts to the extent possible. Some activities 

(particularly those that involve a major revision to an existing stepdown management plan, or preparing a new plan) would need to 

comply with additional laws or regulations besides NEPA and the 

Improvement Act. A list of the Federal laws, executive orders and 

legislative acts is in Appendix M. 

7. Monitoring and Evaluation 

The CCP is designed to be effective for a 15-year period. The plan 

will be reviewed and revised as required to ensure that established 

goals and objectives are still applicable and that the CCP is 

implemented as scheduled. The monitoring program will focus on 

issues involving visitor service activities, habitat management 

programs, wildlife inventory, and other monitoring and management 

activities. Monitoring and evaluation will use the adaptive 

management process. This process includes goal and objective 

setting, and applying management tools and strategies followed by 

monitoring and analysis to measure achievement of objectives and 

refine management techniques. 

Collection of baseline data on wildlife populations will continue. This 

data will be used to update existing species lists, wildlife habitat 

requirements, and seasonal use patterns. Migratory and resident 

birds, raptors, and species of management concern will be the focus 

of monitoring efforts. 

Where information gaps exist, a concerted effort will be made to 

obtain information. With new information, goals and objectives may 

need modification. Public involvement will be encouraged during the 

evaluation process. 

Monitoring of visitor service programs will involve the continued 

collection of visitor use statistics. Monitoring will be done to evaluate 

the effects of public use on Refuge habitat, wildlife populations, and 

visitor experience. 

198 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Plan Implementation 

8. Adaptive Management 

Adaptive management is the process of implementing policy decisions 

as scientifically driven experiments that test predictions and 

assumptions about management plans, using the resulting 

information to improve the plans. Adaptive management provides the 

framework within which biological measures and public use can be 

evaluated by comparing the results of management to results 

expected from objectives. Management direction is periodically 

evaluated within a system that applies several options, monitors the 

objectives, and adapts original strategies to reach desired objectives. 

Habitat, wildlife, and visitor service management techniques and 

specific objectives would be regularly evaluated as results of a 

monitoring program and other new technology and information 

become available. These periodic evaluations would be used over time 

to adapt both the management objectives and strategies to better 

achieve management goals. Such a system embraces uncertainty and 

provides new information for future decision-making while allowing 

resource use. 

Horned lark 

Photo by Steve Emmons 

9. CCP Plan Amendment and Revision 

The CCP is intended to evolve as the Refuges change, and the 

Improvement Act specifically requires that CCPs be formally revised 

and updated at least every 15 years. The formal revision process 

would follow the same steps as the CCP creation process. In the 

meantime, the Service would be reviewing and updating this CCP 

periodically based on the results of the adaptive management 

program. While preparing annual work plans and updating the 

Refuge database, refuge staff will also review the CCP. It may also 

be reviewed during routine inspections or programmatic evaluations. 

Results of any or all of these reviews may indicate a need to modify 

the plan. The goals described in this CCP would not change until they 

are reevaluated as part of the formal CCP revision process. However, 

the objectives and strategies may be revised to better address 

changing circumstances or to take advantage of increased knowledge 

of the resources on the Refuge. It is the intent of the Service to have 

Comprehensive Conservation Plan 199 
Chapter 5 

the CCP apply to any new lands that may be acquired. If changes are 

required, the refuge manager would determine the level of public 

involvement and associated NEPA documentation. 

The intent of the CCP is for the Refuges’ objectives and strategies to 

be attained over the next 15 years. Management activities would be 

phased in over time and implementation is contingent upon and 

subject to results of monitoring and evaluation, funding through 

Congressional appropriations and other sources, and staffing. 

Red-shouldered hawk 

Photo by Steve Emmons 

200 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Glossary 

Glossary 

Adaptive Management: The rigorous application of management, 

research, and monitoring to gain information and experience 

necessary to assess and modify management activities. A process that 

uses feedback from refuge research and monitoring and evaluation of 

management actions to support or modify objectives and strategies at 

all planning levels (Service Manual 602 FW 1.6). 

Alluvial: Pertaining to clay, silt, sand, gravel or other sedimentary 

matter deposited by flowing water, usually within a river valley. 

Alternatives: Different sets of objectives and strategies or means of 

achieving refuge purposes and goals, helping fulfill the Refuge 

System mission, and resolving issues. (1) A reasonable way to fix the 

identified problem or satisfy the stated need. (40 CFR 150.2) (2) 

Alternatives are different sets of objectives and strategies or means 

of achieving refuge purposes and goals, helping fulfill the Refuge 

System mission, and resolving issues (Service Manual 602 FW 1.6). 

Aquatic: Pertaining to water, in contrast to land. Living in or upon 

water. 

Aquatic Habitat: The physical, chemical, and vegetative features 

that occur within the water of lakes, ponds, reservoirs, rivers, 

irrigation canals, and other bodies of water. 

Artifact: An object made by humans; usually in reference to 

primitive tools, vessels, weapons, etc. 

ATV: All Terrain Vehicle (either 3 or 4-wheeled vehicles). 

Biodiversity (biological diversity): Refers to the full range of 

variability within and among biological communities, including 

genetic diversity, and the variety of living organisms, assemblages of 

living organisms, and biological processes. Diversity can be measured 

in terms of the number of different items (species, communities) and 

their relative abundance, and it can include horizontal and vertical 

variability. The variety of life, including the variety of living 

organisms, the genetic differences among them, and the communities 

in which they occur. 

Biological Control: The use of organisms or viruses to control weeds 

or other pests. 

Biological Integrity: Biotic composition, structure, and functioning 

at the genetic, organism, and community levels consistent with 

natural conditions, including the natural biological processes that 

Comprehensive Conservation Plan 201 
Glossary 

shape genomes, organisms, and communities (Service Manual 602 

FW 1.6). 

Biota: The plant and animal life of a region. 

Categorical Exclusion (CE, CX, CATEX, CATX): A category of 

actions that do not individually or cumulatively have a significant 

effect on the human environment and have been found to have no 

such effect in procedures adopted by a Federal agency pursuant to 

the National Environmental Policy Act (40 CFR 1508.4). 

CFR: Code of Federal Regulations. 

Compatible Use: A proposed or existing wildlife-dependent 

recreational use or any other use of a national wildlife refuge that, 

based on sound professional judgment, will not materially interfere 

with or detract from the fulfillment of the National Wildlife Refuge 

System mission or the purposes of the national wildlife refuge 

(Service Manual 603 FW 2.6). 

Compatibility Determination: A written determination signed and 

dated by the refuge manager and Regional Chief signifying that a 

proposed or existing use of a national wildlife refuge is a compatible 

use or is not a compatible use. The Director makes this delegation 

through the Regional Director (Service Manual 603 FW 2.6). 

Comprehensive Conservation Plan (CCP): A document that 

describes the desired future conditions of the refuge or planning unit 

and provides long-range guidance and management direction to 

achieve the purposes of the refuge, helps fulfill the mission of the 

Refuge System; maintains and, where appropriate, restores the 

ecological integrity of each refuge and the Refuge System; helps 

achieve the goals of the National Wilderness Preservation System; 

and meets other mandates (Service Manual 602 FW 1.6). 

Cultural Resource: The physical remains of human activity 

(artifacts, ruins, petroglyphs, etc.) and conceptual content or context 

of an area such as a traditional sacred site. It includes historically, 

archaeologically and architecturally significant resources. 

Cultural Resource Inventory: A professionally conducted study 

designed to locate and evaluate evidence of cultural resources present 

within a defined geographic area. Inventories may involve various 

levels, including background literature search, comprehensive field 

examination to identify all exposed physical manifestations of cultural 

resources, or sample inventory to project site distribution and density 

over a larger area. Evaluation of identified cultural resources to 

determine eligibility for the National Register follows the criteria 

found in 36 CFR 60.4 (Service Manual 614 FW 1.7). 

202 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Glossary 

Cultural Resource Overview: A comprehensive document prepared 

for a field office that discusses, among other things, its prehistory and 

cultural history, the nature and extent of known cultural resources, 

previous research, management objectives, resource management 

conflicts or issues, and a general statement on how program 

objectives should be met and conflicts resolved. An overview should 

reference or incorporate information from a field offices background 

or literature search described in Section VIII of the Cultural 

Resource Management Handbook (Service Manual 614 FW 1.7). 

Deposits: Material that is laid down through the actions of wind, 

water, ice, or other natural process. 

Diversion: A structure in a river or canal that diverts water from the 

river or canal to another water course. 

Drain: A canal that collects and transports excess water from 

irrigated farmland. 

Easement: A privilege or right that is held by one person or other 

entity in land owned by another. 

Ecological Integrity: The integration of biological integrity, natural 

biological diversity, and environmental health; the replication of 

natural conditions (Service Manual 602 FW 1.6). 

Ecology: The branch of biology that studies the interactions of 

organisms within an environment, either with other organisms (biotic 

factors) or with the non-living components (abiotic factors) of that 

ecosystem. 

Ecosystem: The sum of all interacting parts of the environment and 

associated ecological communities within a particular area; an 

ecological system. Many levels of ecosystems have been recognized. 

Very few, if any ecosystems are self-contained; most influence, or are 

influenced by, components or forces outside the system. For 

administrative purposes, we have designated 53 ecosystems covering 

the United States and its possessions. These ecosystems generally 

correspond with watershed boundaries, and their sizes and ecological 

complexity vary. 

Ecosystem Approach: Protecting or restoring the natural function 

(processes), structure (physical and biological patterns), and species 

composition of an ecosystem, recognizing that all components are 

interrelated. 

Effect: A change in a resource, caused by a variety of events 

including project attributes acting on a resource attribute (direct), 

not directly acting on a resource attribute (indirect), another project 

Comprehensive Conservation Plan 203 
Glossary 

attributes acting on a resource attribute (cumulative), and those 

caused by natural events (e.g., seasonal change). 

Emergent Vegetation: Rooted, aquatic plants that have most of 

their vegetative (non-root) parts above water. 

Endemic Species: Plants or animals that occur naturally in a certain 

region and whose distribution is relatively limited to a particular 

locality. 

Endangered Species: Any species that is in danger of extinction 

throughout all or a significant portion of its range and listed as such 

by the Secretary of the Interior in accordance with the Endangered 

Species Act of 1973. Endangered species are afforded protection 

under the Act as amended and under various State laws for Statelisted species. 

Environment: The sum total of all biological, chemical, and physical 

factors to which organisms are exposed; the surroundings of a plant 

or animal. 

Environmental Assessment (EA): A concise public document, 

prepared in compliance with the National Environmental Policy Act, 

that briefly discusses the purpose and need for an action, alternatives 

to such action, and provides sufficient evidence and analysis of 

impacts to determine whether to prepare an environmental impact 

statement or finding of no significant impact (40 CFR 1508.9). 

Environmental Education: A process designed to develop a 

citizenry that has the awareness, concern, knowledge, attitudes, 

skills, motivation, and commitment to work toward solutions of 

current environmental problems and the prevention of new ones. 

Environmental education within the National Wildlife Refuge System 

incorporates materials, activities, programs, and products that 

address the citizen's course of study goals, the objectives of the 

refuge/field station, and the mission of the Refuge System. 

Environmental Health: Abiotic composition, structure, and 

functioning of the environment consistent with natural conditions, 

including the natural abiotic processes that shape the environment 

(Service Manual 602 FW 1.6). 

Environmental Impact Statement (EIS): A detailed written 

statement required by section 102(2) (C) of the National 

Environmental Policy Act, analyzing the environmental impacts of a 

proposed action, adverse effects of the project that cannot be avoided, 

alternative courses of action, short-term uses of the environment 

versus the maintenance and enhancement of long-term productivity, 

and any irreversible and irretrievable commitment of resources (40 

CFR 1508.11). 

204 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

Glossary 

Ephemeral: Pertains to streams, lakes and wetlands that exist 

temporarily each year. 

Evapotranspiration: The collective processes by which water is 

transferred from the surface of the earth, including from the soil and 

the surface of water-bodies (through evaporation) and from plants 

(through transpiration). 

Evolutionary Significant Unit (ESU): A sub-population of a species 

that is defined by substantial reproductive isolation from other 

conspecific units and represents an important component of the 

evolutionary legacy of the species. 

Exotic and Invading Species. (Noxious Weeds): Plant species 

designated by Federal or State law as generally possessing one or 

more of the following characteristics: aggressive or difficult to 

manage; parasitic; a carrier or host of serious insects or disease; or 

nonnative, new, or not common to the United States, according to the 

Federal Noxious Weed Act (PL 93-639), a noxious weed is one that 

causes disease or has adverse effects on man or his environment and 

therefore is detrimental to the agriculture and commerce of the Unite 

States and to the public health. 

Fallow: Allowing land that normally is used for crop production to lie 

idle. 

Federal Trust Resources: A trust is something managed by one 

entity for another who holds the ownership. The Service holds in 

trust many natural resources for the people of the United States of 

America as a result of Federal Acts and treaties. Examples are 

species listed under the Endangered Species Act, migratory birds 

protected by the Migratory Bird Treaty Act and other international 

treaties, and native plant or wildlife species found on the Refuge 

System. 

Finding of No Significant Impact (FONSI): A document prepared 

in compliance with the National Environmental Policy Act, supported 

by an environmental assessment, that briefly presents why a Federal 

action will have no significant effect on the human environment and 

for which an environmental impact statement, therefore, will not be 

prepared (40 CFR 1508.13). 

Floodplain: The relatively flat area along the sides of a river which is 

naturally subjected to flooding. 

Fluvial: Pertaining to a river. 

Flyway: A route taken by migratory birds between their breeding 

grounds and their wintering grounds. Four primary migration routes 

Comprehensive Conservation Plan 205 
 

Glossary 

have been identified for birds breeding in North America: the Pacific, 

Central, Mississippi, and Atlantic Flyways. 

Foraging: The act of feeding; another word for feeding. 

Forbs: Herbaceous dicotyledonous plants. 

Fragmentation: The process of reducing the size and connectivity of 

habitat patches. 

GIS: Geographic Information System. Refers to such computer 

mapping programs as ArcView, ArcInfo, ERDAS, etc. 

Goal: Descriptive, open-ended, and often broad statement of desired 

future conditions that conveys a purpose but does not define 

measurable units (Service Manual 620 FW 1.6). 

Habitat: Suite of existing environmental conditions required by an 

organism for survival and reproduction. The place where an organism 

typically lives. 

Habitat Restoration: Management emphasis designed to move 

ecosystems to desired conditions and processes, and/or to healthy 

forestlands, rangelands, and aquatic systems. 

Halophytes: Salt-tolerant plant species. 

Hydrologic Regime: The local pattern and magnitude of water flow 

influenced by season. 

Hydrology: The science dealing with the properties, distribution, and 

circulation of water on and below the earth's surface and in the 

atmosphere. The distribution and cycling of water in an area. 

Impoundment: A body of water created by collection and 

confinement within a series of levees or dikes thus creating separate 

management units although not always independent of one another. 

Impact: See effect. 

Indigenous: Native to the area. 

Integrated Pest Management (IPM): The control of pests utilizing a 

practical, economical and scientifically based combination of 

biological, physical, cultural and chemical control methods. 

Integrated pest management emphasizes these methods in order to 

reduce or eliminate the need for chemical pesticides. It is a balanced 

approach, which considers hazard to the environment, efficacy, costs 

and vulnerability of the pest (Service Administrative Manual 30 AM 

12). 

206 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Glossary 

Interpretation: Interpretation can be an educational and 

recreational activity that is aimed at revealing relationships, 

examining systems, and exploring how the natural world and human 

activities are interconnected. 

Invasive species: A species that is a non-native (or alien) to the 

ecosystem under consideration and whose introduction causes or is 

likely to cause economic or environmental harm or harm to human 

health. (Executive Order 13112). Invasive species can be plants, 

animals, and other organisms (e.g., microbes). Human actions are the 

primary means of invasive species introductions. 

Invertebrate: Animals that do not have backbones. Included are 

insects, spiders, mollusks (clams, snails, etc.), and crustaceans 

(shrimp, crayfish, etc.). 

Irrigation Drainwater: Ideally, subsurface water which flows from 

irrigated land and generally transports higher concentrations of 

dissolved salts than the water applied to the land. 

Issue: Any unsettled matter that requires a management decision, 

e.g., an initiative, opportunity, resource management problem, threat 

to the resources of the unit, conflict in uses, public concern, or the 

presence of an undesirable resource condition (Service Manual 602 

FW 1.6). 

Landowner: A person or entity indicated as the owner of property on 

the various ownership maps maintained by the Office of the County 

Assessor. 

Landscape Ecology: A sub-discipline of ecology, which focuses on 

spatial relationships and interactions between patterns and 

processes. This emerging science integrates hydrology, geology, 

geomorphology, soil science, vegetation science, wildlife science, 

economics, sociology, law, engineering and land use planning to 

conserve, enhance, restore and protect the sustainability of 

ecosystems on the land. 

Lease: A legal contract by which water rights are acquired for a 

specified period of time for a specified rent or compensation. 

Levee: An embankment along the river to prevent water from over 

bank flooding. 

Marsh: A periodically wet or continually flooded area where the 

water is shallow enough to allow the growth of emergent vegetation 

such as sedges, rushes, and cattails. 

Comprehensive Conservation Plan 207 
Glossary 

Meander: The bend of curve in a river or stream channel. Migration 

of the river or stream channel. 

Migration: The seasonal movement from one area to another and 

back. 

Migratory Bird: A bird that seasonally moves between geographic 

areas. In reference to birds in the Great Basin, a bird that breeds in 

Great Basin and subsequently moves south of the Great Basin for the 

winter months. Birds that migrate south of Mexico for the winter are 

considered Neotropical migrants. 

Mission Statement: Succinct statement of the unit's purpose and 

reason for being. 

Mitigation: To avoid or minimize impacts of an action by limiting the 

degree or magnitude of the action; to rectify the impact by repairing, 

rehabilitating, or restoring the affected environment; to reduce or 

eliminate the impact by preservation and maintenance operations 

during the life of the action. 

Moist-Soil: A process where water is drawn down intentionally or 

naturally to produce mudflats (i.e., moist soil) that is required for 

germination of many desirable plants. 

Monitoring: Data collected and analyzed periodically for comparing 

trends in that which is being monitored. Monitoring is necessary to 

identify, track and analyze results of management actions at the 

refuge so that future management actions may be adapted to obtain 

the best benefits to wildlife and habitat (see adaptive management). 

National Environmental Policy Act (NEPA): An act which 

encourages productive and enjoyable harmony between humans and 

their environment, to promote efforts that will prevent or eliminate 

damage to the environment and atmosphere, to stimulate the health 

and welfare of humans. The act also established the Council on 

Environmental Quality (CEQ). Requires all agencies, including the 

Service, to examine the environmental impacts of their actions, 

incorporate environmental information, and use public participation 

in the planning and implementation of all actions. Federal agencies 

must integrate NEPA with other planning requirements, and 

prepare appropriate NEPA documents to facilitate better 

environmental decision making (from 40 CFR 1500). 

National Wildlife Refuge (Refuge or NWR): A designated area of 

land or water or an interest in land or water within the system, 

including national wildlife refuges, wildlife ranges, wildlife 

management areas, waterfowl production areas, and other areas 

(except coordination areas) under the Service jurisdiction for the 

protection and conservation of fish and wildlife. A complete listing of 

208 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Glossary 

all units of the Refuge System may be found in the current AReport of 

Lands Under Control of the U.S. Fish and Wildlife Service@ (Service 

Manual 602 FW 1.6). 

National Wildlife Refuge System (Refuge System): Various 

categories of areas that are administered by the Secretary for the 

conservation of fish and wildlife, including species that are threatened 

with extinction; all lands, waters, and interest therein administered 

by the Secretary as wildlife refuges; areas for the protection and 

conservation of fish and wildlife that are threatened with extinction; 

wildlife ranges; game ranges; wildlife management or waterfowl 

production areas. 

National Wildlife Refuge System Mission (mission): "The mission 

of the System is to administer a national network of lands and waters 

for the conservation, management, and, where appropriate, 

restoration of the fish, wildlife, and plant resources and their habitats 

within the United States for the benefit of present and future 

generations of Americans" (Service Manual 602 FW 1.6). 

Natural Recruitment: Plant establishment through natural 

processes. In riparian systems these processes include: flooding, 

sediment deposition, erosion, and seed dispersal from local or 

upstream plant sources. 

Native Species: Species that normally live and thrive in a particular 

ecosystem. 

Neotropical Migratory Birds: Migratory birds that breed in North 

American and winter in Central and South America. 

NEPA: National Environmental Policy Act of 1969. 

Niche: An organism's "place," or role, in an ecosystem. This involves 

many components of the organism's life: where it lives (habitat), what 

it eats, by whom it is eaten, when it migrates or breeds, etc. All of 

these factors combine to determine the role of the organism in its 

ecosystem. 

No Action Alternative: An alternative under which existing 

management would be continued. 

Non-Priority Public Uses: Any use other than a compatible wildlifedependent recreational use. 

Notice of Intent (NOI): A notice that an environmental impact 

statement will be prepared and considered (40 CFR 1508.22). 

Published in the Federal Register. 

NWR: National Wildlife Refuge. 

Comprehensive Conservation Plan 209 
 

 

Glossary 

Objective: A concise statement of what we want to achieve, how much 

we want to achieve, when and where we want to achieve it, and who is 

responsible for the work. Objectives derive from goals and provide 

the basis for determining strategies, monitoring refuge 

accomplishments, and evaluating the success of strategies. Make 

objectives attainable, time-specific, and measurable (Service Manual 

602 FW 1.6). 

One-hundred-year Floodplain: The relatively flat portion of the 

river channel that has a one percent chance of being inundated by 

flood water in any given year. 

Outreach: Outreach is two-way communication between the USFWS 

and the public to establish mutual understanding, promote 

involvement, and influence attitudes and actions, with goal of 

improving joint stewardship of our natural resources. 

Over bank Flooding: River flows that exceed the boundaries of the 

existing river channel and flood the adjacent riparian areas and 

bottomlands. 

Oxbow Lake: A horseshoe-shaped lake formed in an abandoned 

meander bend of a river. 

Passerine Bird: A songbird or other perching bird that is in the 

order Passeriformes. Blackbirds, crows, warblers, sparrows, and 

wrens for example. 

Perennial: In reference to a body of water, one that contains water 

year-to-year and that rarely goes dry. 

Peak Flow: The maximum discharge of a stream during a specified 

period of time. 

Pest: Any terrestrial or aquatic plant or animal which interferes, or 

threatens to interfere, at an unacceptable level, with the attainment 

of refuge objectives or which poses a threat to human health (Refuge 

Manual 7 RM 14). 

Phenology: Life cycle of particular species. 

Physiographic: Physical geography of a particular region of the U.S. 

PILT: Payment-in-Lieu-of-Taxes. 

Planning Area: The area upon which the planning effort will focus. A 

planning area may include lands outside existing planning unit 

boundaries currently studied for inclusion in the Refuge System 

and/or partnership planning efforts. It also may include watersheds 

210 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Glossary 

or ecosystems outside of our jurisdiction that affect the planning unit. 

At a minimum, the planning area includes all lands within the 

authorized boundary of the refuge (Service Manual 602 FW 1.6). 

Planning Team: A team or group of persons working together to 

prepare a document. Planning teams are interdisciplinary in 

membership and function. Teams generally consist of a planning 

team leader, refuge manager and staff biologists, a state natural 

resource agency representative, and other appropriate program 

specialists (e.g., social scientist, ecologist, recreation specialist). We 

also will ask other Federal and Tribal natural resource agencies to 

provide team members, as appropriate. The planning team prepares 

the CCP and appropriate NEPA documentation (Service Manual 602 

FW 1.6). 

Planning Team Leader: The planning team leader typically is a 

professional planner or natural resource specialist knowledgeable of 

the requirements of NEPA and who has planning experience. The 

planning team leader manages the refuge planning process and 

ensures compliance with applicable regulatory and policy 

requirements (Service Manual 602 FW 1.6). 

Planning Unit: A single refuge, an ecologically or administratively 

related refuge complex, or distinct unit of a refuge. The planning unit 

also may include lands currently outside refuge boundaries (Service 

Manual 602 FW 1.6). 

Plant Community: An assemblage of plant species of a particular 

composition. The term can also be used in reference to a group of one 

or more populations of plants in a particular area at a particular point 

in time; the plant community of an area can change over time due to 

disturbance (e.g., fire) and succession. 

Pollutant: Any introduced gas, liquid, or solid that makes a resource 

unfit for a specific purpose. 

Population: All the members of a single species coexisting in one 

ecosystem at a given time. 

Preferred Alternative: This is the alternative determined (by the 

decision maker) to best achieve the Refuge purpose, vision, and goals; 

contributes to the Refuge System mission, addresses the significant 

issues; and is consistent with principles of sound fish and wildlife 

management. The Service=s selected alternative at the Draft CCP 

stage. 

Prescribed Fire: The skillful application of fire to natural fuels under 

conditions of weather, fuel moisture, soil moisture, etc., that allows 

confinement of the fire to a predetermined area and produces the 

intensity of heat and rate of spread to accomplish planned benefits to 

Comprehensive Conservation Plan 211 
Glossary 

one or more objectives of habitat management, wildlife management, 

or hazard reduction. 

Priority Public Uses: Compatible wildlife-dependent recreation uses 

(hunting, fishing, wildlife observation and photography, and 

environmental education and interpretation). 

Proposed Action: The Service=s proposed action for Comprehensive 

Conservation Plans is to prepare and implement the CCP. 

Public: Individuals, organizations, and groups; officials of Federal, 

State, and local government agencies; Indian tribes; and foreign 

nations. It may include anyone outside the core planning team. It 

includes those who may or may not have indicated an interest in 

Service issues and those who do or do not realize that Service 

decisions may affect them. 

Public Involvement: A process that offers impacted and interested 

individuals and organizations an opportunity to become informed 

about, and to express their opinions on Service actions and policies. 

In the process, these views are studied thoroughly and thoughtful 

consideration of public views is given in shaping decisions for refuge 

management. 

Public Scoping: Using news releases to the local media and other 

appropriate means, notify the affected public of the opportunity to 

participate in the preparation of the CCP and begin the scooping 

process. Involve the public and gather comments on any existing 

planning unit vision statement and goals. Encourage the public to 

help identify potential issues, management actions and concerns, 

significant problems or impacts, and opportunities or alternatives to 

resolve them (Service Manual 602 FW 3). 

Purposes of the Refuge: "The purposes specified in or derived from 

the law, proclamation, executive order, agreement, public land order, 

donation document, or administrative memorandum establishing, 

authorizing, or expanding a refuge, refuge unit, or refuge subunit." 

For refuges that encompass congressionally designated wilderness, 

the purposes of the Wilderness Act are additional purposes of the 

refuge (Service Manual 602 FW 1.6). 

Raptor: A bird of prey, such as a hawk, eagle, or owl. 

Record of Decision (ROD): A concise public record of decision 

prepared by the Federal agency, pursuant to NEPA, that contains a 

statement of the decision, identification of all alternatives considered, 

identification of the environmentally preferable alternative, a 

statement as to whether all practical means to avoid or minimize 

environmental harm from the alternative selected have been adopted 

212 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

Glossary 

(and if not, why they were not), and a summary of monitoring and 

enforcement where applicable for any mitigation (40 CFR 1505.2). 

Recruitment: The annual increase in a population as determined by 

the proportion of surviving offspring produced during a specific 

period (usually expressed per year). 

Refuge: Short of National Wildlife Refuge. 

Refuge Goal: See goal. 

Refuge Operating Needs System (RONS): The Refuge Operating 

Needs System is a national database that contains the unfunded 

operational needs of each refuge. We include projects required to 

implement approved plans and meet goals, objectives, and legal 

mandates (Service Manual 602 FW 1.6). 

Refuge Purposes: See purposes of the Refuge. 

Refuge Revenue Sharing Program or RRSP: Proves payments to 

counties in lieu of taxes using revenues derived from the sale of 

products from refuges. 

Refuge Use: Any activity on a refuge, except administrative or law 

enforcement activity carried out by or under the direction of an 

authorized Service employee. 

Restoration: The return of an ecosystem to an approximation of its 

former unimpaired condition. 

Riparian Area: Riparian areas are transitional between terrestrial 

and aquatic ecosystems and are distinguished by gradients in 

biophysical conditions, ecological processes, and biota. They are areas 

through which surface and subsurface hydrology connect waterbodies 

with their adjacent uplands. They include those portions of terrestrial 

ecosystems that significantly influence exchanges of energy and 

matter with aquatic ecosystems (i.e., a zone of influence). Riparian 

areas are adjacent to perennial, intermittent, and ephemeral streams, 

lakes and estuarine-marine shorelines. 

Riparian Habitat: Gravel bars, sand dunes, non-vegetated 

riverbanks, herbaceous, scrub and forested vegetation, which 

provides habitat for plants, macro-invertebrates, fish and wildlife. 

Riverine: Pertaining to rivers and floodplains. 

Secretary: Short of the Secretary of the Interior. 

Comprehensive Conservation Plan 213 
Glossary 

Sediment: Any material, carried in suspension by water, which 

ultimately settles to the bottom of water courses. Sediments may also 

settle on stream banks or flood plains during high water flow. 

Service or USFWS: Short for U.S. Fish and Wildlife Service. 

Shorebirds: Long-legged birds, also known as waders, belonging to 

the Order Charadriiformes that use shallow wetlands and mud flats 

for foraging and nesting. 

Slough: A naturally occurring side or overflow channel that holds 

water. 

Soil Erosion: The wearing away of the land's surface by water, wind, 

ice, or other physical process. 

Sound Professional Judgment: A finding, determination, or decision 

that is consistent with principles of sound fish and wildlife 

management and administration, available science and resources, and 

adherence to the requirements of the Refuge Administration Act of 

1966 (16 U.S.C. 668dd-668ee), and other applicable laws. Included in 

the finding, determination, or decision is a refuge manager’s field 

experience and knowledge of the particular refuge’s resources 

(Service Manual 603 FW 2.6). 

Species: A distinctive kind of plant or animal having distinguishable 

characteristics, and that can interbreed and produce young. A 

category of biological classification. 

Species Composition: A group of species that inhabit a specific 

habitat type in its healthy state. To enhance species composition is to 

ensure that all or as many species as possible inhabit the appropriate 

habitat by improving the quality of that habitat. 

Step-Down Management Plan: A plan that provides specific 

guidance on management subjects (e.g., habitat, public use, fire, 

safety) or groups of related subjects. It describes strategies and 

implementation schedules for meeting CCP goals and objectives 

(Service Manual 602 FW 1.6). 

Strategy: A specific action, tool, or technique or combination of 

actions, tools, and techniques used to meet unit objectives (Service 

Manual 602 FW 1.6). 

Submergent Vegetation: Plants that grows completely submerged 

except when flowering. 

Succession: The replacement of one plant community by another 

over time. 

214 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Glossary 

Surface Water: A body of water that has its upper surface exposed 

to the atmosphere. 

System or Refuge System: National Wildlife Refuge System. 

Threatened Species: Any species that is likely to become an 

endangered species within the foreseeable future throughout all or a 

significant portion of its range, and one that has been designated as a 

threatened species in the Federal Register by the Secretary of the 

Interior. Threatened species are afforded protection under the 

Endangered Species Act of 1973. 

Trust Species: Species for which the U.S. Fish and Wildlife Service 

has primary responsibility, including, most federally listed 

threatened and endangered species, anadromous fishes once they 

enter inland U.S. waterways, migratory birds, and certain marine 

mammals. 

Understory: Shrubs and herbaceous plants that typically grow 

beneath larger trees in a woodland. 

Upland: An area where water normally does not collect and where 

water does not flow on an extended basis. Uplands are non-wetland 

areas. 

USFWS or Service: Short for U.S. Fish and Wildlife Service. 

U.S. Fish and Wildlife Service Mission: Our mission is working 

with others to conserve, protect, and enhance fish, wildlife, and plants 

and their habitats for the continuing benefit of the American people 

(Service Manual 602 FW 1.6). 

Vegetation: The composition plant species, their frequency of 

occurrence, density, and age classes at a specified scale. 

Vegetation Type or Habitat Type: A land classification system 

based upon the concept of distinct plant associations. 

Vernal Pool: Seasonally flooded depressions on soils with an 

impermeable layer such as a hardpan, claypan, volcanic basalt, or 

saturated alkali clays. The impermeable layer allows the pools to 

retain water much longer then the surrounding uplands; nonetheless, 

the pools are shallow enough to dry up each season. Vernal pools 

often fill and empty several times during the rainy season. Only 

plants and animals that are adapted to this cycle of wetting and 

drying can survive in vernal pools over time. 

Vertebrate: An animal having a segmented backbone or vertebral 

column; includes mammals, birds, fish, amphibians, and reptiles. 

Comprehensive Conservation Plan 215 
Glossary 

Vision Statement: A concise statement of what the planning unit 

should be, or what we hope to do, based primarily upon the Refuge 

System mission and specific refuge purposes, and other mandates. 

We will tie the vision statement for the refuge to the mission of the 

Refuge System; the purpose(s) of the refuge; the maintenance or 

restoration of the ecological integrity of each refuge and the Refuge 

System; and other mandates (Service Manual 602 FW 1.6). 

Waterfowl: A group of birds that include ducks, geese, and swans 

(belonging to the order Anseriformes). 

Water Rights: A grant, permit, decree, appropriation, or claim to the 

use of water for beneficial purposes, and subject to other rights of 

earlier date of use, called priority, or prior appropriation. 

Watershed: The entire land area that collects and drains water into a 

river or river system. 

Wetland: Land that is transitional between upland (terrestrial) and 

aquatic systems (greater than about 6-feet deep) where the water 

table is usually at or near the surface or the land is covered by 

shallow water... wetlands must have one or more of the following 

three attributes: (1) at least periodically, the land supports 

predominantly hydrophytes (plants that require wet conditions); (2) 

the substrate is predominantly undrained hydric soil; and (3) the 

substrate is non-soil and is saturated with water or covered by 

shallow water at some time during the growing season of each year 

(Cowardin and others, 1979). 

Wetland Habitat: Habitat provided by shallow or deep water (but 

less than 6-feet deep), with or without emergent and aquatic 

vegetation in wetlands. Wetland habitat only exists when and where a 

wetland or portion of a wetland is covered with water (visible surface 

water). Consequently, the size and shape of "wetland habitat" will 

fluctuate from season-to-season and year-to-year while the size and 

shape of the "wetland" within which wetland habitat occurs will 

remain constant from season to season and from year to year. 

Wetlands only provide habitat for waterfowl, shorebirds, muskrats, 

aquatic insects, and other wetland-dependent wildlife when they 

contain surface water (i.e., when they provide wetland habitat). 

Wildfire: A free-burning fire requiring a suppression response; all 

fire other than prescribed fire that occurs on wildlands (Service 

Manual 621 FW 1.7). 

Wildland fire: A free burning fire requiring a suppression response; 

all fire other than prescribed fire that occurs on wildlands. Often 

referred to as a wildfire. 

216 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
Glossary 

Wildlife: All non-domesticated animal life; included are vertebrates 

and invertebrates. 

Wildlife Corridor: A landscape feature that facilitates the 

biologically effective transport of animals between larger patches of 

habitat dedicated to conservation functions. Such corridors may 

facilitate several kinds of traffic, including frequent foraging 

movement, seasonal migration, or the once in a lifetime dispersal of 

juvenile animals. These are transition habitats and need not contain 

all the habitat elements required for long-term survival of 

reproduction of its migrants. 

Wildlife-Dependent Recreational Use: "A use of a refuge involving 

hunting, fishing, wildlife observation and photography, or 

environmental education and interpretation." These are the six 

priority public uses of the Refuge System as established in the 

National Wildlife Refuge System Administration Act, as amended. 

Wildlife-dependent recreational uses, other than the six priority 

public uses, are those that depend on the presence of wildlife. We also 

will consider these other uses in the preparation of refuge CCPs; 

however, the six priority public uses always will take precedence 

(Service Manual 602 FW 1.6). 

Comprehensive Conservation Plan 217 
Glossary 

218 Sacramento, Delevan, Colusa, and Sutter National Wildlife Refuges 
 

 

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