i

DISCLAIMER 

Recovery plans delineate actions which the best available science 

indicates are required to recover and protect listed species. Plans are published by 

the U.S. Fish and Wildlife Service and sometimes prepared with the assistance of 

recovery teams, contractors, State agencies, and others. Recovery teams serve as 

independent advisors to the U.S. Fish and Wildlife Service. Recovery plans are 

reviewed by the public and submitted to additional peer review before they are 

approved and adopted by the U.S. Fish and Wildlife Service. Objectives will be 

attained and any necessary funds made available subject to budgetary and other 

constraints affecting the parties involved, as well as the need to address other 

priorities. Nothing in this plan should be construed as a commitment or 

requirement that any Federal agency obligate or pay funds in contravention of the 

Anti-Deficiency Act, 31 USC 1341, or any other law or regulation. Recovery 

plans do not necessarily represent the views nor the official positions or approval 

of any individuals or agencies involved in the plan formulation, other than the 

U.S. Fish and Wildlife Service. Recovery plans represent the official position of 

the U.S. Fish and Wildlife Service only after they have been signed as approved

by the Regional Director or Director. Approved recovery plans are subject to 

modification as dictated by new findings, changes in species status, and the 

completion of recovery actions. Please check for updates or revisions at the 

website addresses provided below before using this plan. 

Literature citation of this document should read as follows: 

U.S. Fish and Wildlife Service. 2008. Final Revised Recovery Plan for the Sihek 

or Guam Micronesian Kingfisher (Halcyon cinnamomina cinnamomina). 

Portland, Oregon. x + 117 pp. 

An electronic copy of this plan will be made available at: 

< http://www.fws.gov/pacific/ecoservices/endangered/recovery/rec_plan.html > 

and also at <http://endangered.fws.gov/recovery/index.html>. 
ii

ACKNOWLEDGEMENTS 

Guam Micronesian Kingfisher Recovery Committee 

Fred Amidon, U.S. Fish and Wildlife Service 

Beth Bahner, Philadelphia Zoo 

Aliza Baltz, Philadelphia Zoo 

Anne Brooke, U.S. Navy 

Tina De Cruz, formerly of Commonwealth of the Northern Mariana Islands 

Division of Fish and Wildlife 

Scott Derrickson, Conservation and Research Center, National Zoological Park 

Joanne Earnhardt, Lincoln Park Zoo 

Sue Haig, U.S. Geological Survey, Biological Resources Discipline 

Dylan Kesler, University of Missouri 

Mike McElligot, U.S. Air Force 

Suzanne Medina, Guam Division of Aquatic and Wildlife Resources 

Paul Radley, Commonwealth of the Northern Mariana Islands Division of Fish 

and Wildlife 

Gordon Rodda, U.S. Geological Survey, Biological Resources Discipline 

Dan Vice, U.S. Department of Agriculture, Wildlife Services 

Jonathan Wald, U.S. Air Force 

Jeffrey Walters, Virginia Polytechnic Institute and State University 

Robert Wescom, U.S. Navy 
iii

This revised recovery plan was prepared by the U.S. Fish and Wildlife 

Service in cooperation with the Guam Micronesian Kingfisher Recovery 

Committee. Its completion would not have been possible without the assistance 

of the entire Recovery Committee. 

We would also like to thank the American Zoo and Aquarium Association’s 

Micronesian Kingfisher Species Survival Plan and its participating institutions, 

specifically the Brookfield Zoo, Lincoln Park Zoo, Disney’s Animal Kingdom, 

Houston Zoo, Milwaukee County Zoo, National Zoological Park, the National 

Zoo’s Conservation and Research Center, Philadelphia Zoological Garden, St. 

Louis Zoological Park, San Diego Zoo, and San Diego Wild Animal Park for their 

dedication and commitment to Guam Micronesian kingfisher propagation and 

recovery. In addition we would like to thank the Audubon Park and Zoological 

Garden, Cincinnati Zoo and Botanical Garden, Denver Zoological Gardens, 

Discovery Island Zoological Park, Kansas City Zoological Gardens, Lowry Park 

Zoological Garden, Bronx Zoo/Wildlife Conservation Park, Phoenix Zoo, 

National Aviary in Pittsburgh, Riverbanks Zoological Park, San Antonio 

Zoological Gardens and Aquarium, and Sea World of Florida for their previous 

participation in the Guam Micronesian kingfisher captive propagation program. 

All of the current and past participants in the program have committed a great 

deal of time and resources toward the conservation of this species. Without their 

generosity and dedication the sihek might not exist today. Finally, we would like 

to thank the four peer reviewers of the draft revised recovery plan: Joe Barkowski, 

Sedgewick County Zoo; Mark Meyers, Audubon Zoo; Dr. Gad Perry, Texas Tech 

University; and Bob Seibels, Riverbanks Zoological Park and Botanical Gardens

. 
 

iv

EXECUTIVE SUMMARY 

Current Status: The Guam Micronesian kingfisher or sihek (Halcyon 

cinnamomina cinnamomina) was listed as an endangered subspecies in 1984 (U.S. 

Fish and Wildlife Service [USFWS] 1984). By 1988 the sihek had been 

extirpated from the wild, and this subspecies is now found only in captivity. As 

of May 2008 the population consisted of 60 males, 36 females, and 4 unsexed 

chicks distributed among 17 captive propagation institutions in the mainland 

United States and Guam. The sihek has a recovery priority number of 6 on a 

scale of 1 (highest) to 18 (lowest), reflecting a high degree of threat, relatively 

low prospects for recovery, and its taxonomic status as a subspecies. 

Habitat Requirements and Limiting Factors: Prior to its extirpation from 

the wild, the sihek was found only on the island of Guam. This kingfisher utilized 

a wide variety of habitats on the island including limestone forest, strand forest, 

ravine forest, agricultural forest, secondary forest, edge habitats, and forest 

openings. However, mature forests with appropriate nest sites may be an 

important component of sihek reproductive activities. The sihek is a cavity nester 

and apparently requires large, standing dead trees (nest trees were reported as 

averaging 43 centimeters (17 inches) in diameter) in which to excavate nests 

(Marshall 1989). Diverse vegetative structure providing a variety of both 

invertebrate and vertebrate prey, as well as exposed perches and areas of open 

ground for foraging, are also important components of suitable habitat. 

Habitat degradation and loss, human persecution, contaminants, and 

introduced species such as disease organisms, cats (Felis catus), rats (Rattus spp.), 

black drongos (Dicrurus macrocercus), monitor lizards (Varanus indicus), and 

brown treesnakes (Boiga irregularis) have all been suggested as factors in the 

population decline of this species. However, predation by the brown treesnake is 

believed to have been the overriding factor in the extirpation of sihek. Factors 

that continue to prevent the recovery of the sihek include poor reproductive 

success and high mortality in the captive population and the continued high 

density of brown treesnakes on Guam. Therefore, the majority of the recovery 

actions in this recovery plan address the brown treesnake threat and captive 

propagation issues. Habitat loss and degradation were not considered a major 
 

v

threat due to the availability of suitable forest on Guam. However, this threat is 

increasing and may limit recovery as the island of Guam becomes further 

developed and additional forested areas are cleared or modified and feral ungulate 

populations remain high. 

Recovery Strategy: Recovery actions in this plan are designed to address the 

threats to the sihek and achieve the recovery objectives for this species. Recovery 

actions focus on increasing the size of the captive population, controlling brown 

treesnakes, protecting and enhancing habitat for reintroduction, and reintroducing 

the sihek into the wild on Guam. Establishing a captive breeding program on 

Guam may alleviate some of the problems that have been encountered with efforts 

to increase the captive population in the continental United States. At the same 

time, the ongoing efforts to increase reproductive success and decrease mortality 

in the captive population in the continental United States must also continue. 

Controlling brown treesnakes includes development of new control techniques 

and implementation and testing of existing techniques in the field. Required 

habitat protection and enhancement include: protecting sufficient areas from 

development; controlling ungulates, weeds, and fires; and replanting native plants 

in degraded areas, as needed. Reintroducing the sihek to Guam is essential to the 

recovery of the species, and will require developing appropriate techniques, 

selecting and managing suitable release sites, and releasing sihek to the wild. 

Recovery will require the establishment of at least two subpopulations of sihek on 

Guam to reduce the subspecies’ vulnerability to environmental fluctuations and 

natural or unnatural catastrophes. One subpopulation should occur in northern 

Guam and one in southern Guam. 

Recovery Goals and Objectives: The primary goals of this recovery plan 

are to first downlist the sihek to threatened status, and ultimately to recover the 

sihek to the point that it may be removed from the Federal list of threatened and 

endangered species. These goals will be attained by increasing the captive 

population to a level sufficient to allow reintroductions on Guam, reestablishing a 

wild population of sihek on Guam, and increasing this wild population to attain at 

least two viable, self-sustaining subpopulations through initial population 

augmentation and the control of identified threats. 
 

vi

Downlisting Criteria: The sihek may be considered for downlisting from 

endangered to threatened status when all of the following criteria are met: 

Criterion 1: Sihek occur in 2 subpopulations (one in northern Guam and one in 

southern Guam) of at least 500 adults each; 

Criterion 2: Both subpopulations are either stable or increasing based on 

quantitative surveys or demographic monitoring that demonstrates 

an average intrinsic population growth rate (λ, or lambda) of 

greater than 1.0 over a period of at least 5 consecutive years; 

Criterion 3: Sufficient sihek habitat, based on quantitative estimates of territory 

and home range size, is protected and managed to achieve criteria 

1 and 2 above; and 

Criterion 4: Brown treesnakes and other introduced predators are controlled 

over 5 consecutive years at a level sufficient to achieve criteria 1 

and 2 above. 

Delisting Criteria: The sihek may be removed from the Federal list of 

endangered and threatened species when all of the following criteria are met: 

Criterion 1: Sihek occur in 2 subpopulations (one in northern Guam and one in 

southern Guam) of at least 1,000 adults each; 

Criterion 2: Both subpopulations are either stable or increasing based on 

quantitative surveys or demographic monitoring that demonstrates 

an average intrinsic population growth rate (λ, or lambda) of 

greater than 1.0 over a period of at least 10 consecutive years; 

Criterion 3: Sufficient sihek habitat, based on quantitative estimates of territory 

and home range size, is protected and managed to achieve criteria 

1 and 2 above; and 

Criterion 4: Brown treesnakes and other introduced predators are controlled 

over 10 consecutive years at a level sufficient to achieve criteria 1 

and 2 above. 
 

vii

Actions Needed: The goal of this recovery plan is to reestablish a viable 

population of sihek on Guam. Therefore, this plan focuses on the following 

actions to make this possible: 

(1) Coordinate and monitor recovery efforts; 

(2) Restore populations; 

To prevent extinction of the sihek, the highest priority recovery action is 

to increase the size of the captive population. This is to be accomplished 

by continuing to establish a captive propagation program for the 

subspecies on Guam (Recovery Action 2.2), increasing reproductive 

success of the captive population, and decreasing juvenile and adult 

mortality in the captive population (Recovery Action 2.3). Once the 

captive population is of a sufficient size (Recovery Action 2.1) to allow 

for reintroduction of the subspecies into the wild, sihek should be 

reestablished on Guam. Reintroduction to Guam requires a thorough 

reintroduction program (Recovery Actions 3.1 – 3.8). 

(3) Manage factors affecting population viability; 

Extensive predator control efforts are needed, especially brown treesnake 

control (Recovery Action 4.1). Once sihek have been reestablished in the 

wild, monitoring for additional threats to the subspecies (Recovery Action 

4.2-4.6) would receive increased focus. 

(4) Implement habitat protection and management program; 

In addition to habitat protection and restoration, predator control efforts 

would be expanded to additional areas. 

(5) Develop a public awareness program for sihek. 

Total Estimated Cost of Recovery: Total estimated cost of recovery is 

$145,830,000 over an estimated 50-year period that may be required to recover 

sihek. Approximately $39,200,000 of this total cost will be needed during the 

first 5 years of recovery implementation. The total cost of recovery is only an 

estimate and may change substantially as efforts to recover the subspecies 

continue. In addition, up to $132,550,000 of the total cost is expected to 

contribute to the recovery of the threatened Mariana fruit bat or fanihi (Pteropus 

mariannus mariannus) and the endangered Mariana crow or aga (Corvus 

kubaryi), and will also benefit other listed species on Guam. A detailed cost 
 

viii

breakdown with expected annual costs for the first 5 years of recovery 

implementation is provided in the Implementation Schedule. 

The 50-year and first 5-year costs referenced above are broken down by 

recovery action priority number as follows: 

Priority 1 Actions - Those actions that must be taken to prevent extinction or 

prevent the subspecies from declining irreversibly in the foreseeable future. 

a. 50 Years: $2,950,000+ 

b. 5 Years: $580,000+ 

Priority 2 Actions - Those actions that must be taken to prevent a significant 

decline in population or habitat quality, or some other significant negative 

impact short of extinction. 

a. 50 Years: $133,430,000+ 

b. 5 Years: $36,830,000+ 

Priority 3 Actions - All other actions necessary to meet recovery objectives. 

a. 50 Years: $9,450,000+ 

b. 5 Years: $1,790,000+ 

Estimated Date of Recovery: Our best estimate at this time is that recovery 

of the sihek may require approximately 50 years. It is difficult to accurately 

project a recovery date at this time due to the low number of sihek in the captive 

population and the extensive efforts needed prior to attempting to reestablish the 

subspecies in the wild for the purposes of recovery. 
ix

TABLE OF CONTENTS 

Page

I. Background and Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

A. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

B. Guam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

C. Species Description and Taxonomy. . . . . . . . . . . . . . . . . . . . . . . . . 5

D. Population Trends and Distribution . . . . . . . . . . . . . . . . . . . . . . . . 7

E. Life History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

 1. Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

 2. Space Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

 3. Reproduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

 4. Food Habits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

F. Habitat Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

G. Critical Habitat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

H. Reasons for Decline and Current Threats . . . . . . . . . . . . . . . . . . . . 17

 1. Habitat Degradation and Destruction . . . . . . . . . . . . . . . . . 18

 2. Avian Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

 3. Predation by Brown Treesnakes . . . . . . . . . . . . . . . . . . . . . 21

 4. Other Introduced Predators . . . . . . . . . . . . . . . . . . . . . . . . 23

 5. Human Exploitation and Persecution . . . . . . . . . . . . . . . . 24

 6. Contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

 7. Competition and Harassment by Black Drongos . . . . . . . . 25

 8. Limited Population Growth in Captivity . . . . . . . . . . . . . . 25

I. Conservation Efforts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

 1. Captive Breeding Program . . . . . . . . . . . . . . . . . . . . . . . . . 27

 2. Reduce Avian Mortality in the Field . . . . . . . . . . . . . . . . . 29

 3. Habitat Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

 4. Public Awareness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

II. Recovery Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

A. Recovery Goals, Objectives, and Criteria . . . . . . . . . . . . . . . . . . . 40

1. Recovery Goals and Objectives . . . . . . . . . . . . . . . . . . . . 40

 2. Recovery Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

III. Recovery Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

A. Step-down Outline of Recovery Actions . . . . . . . . . . . . . . . . . . 44
x

B. Narrative Outline of Recovery Actions . . . . . . . . . . . . . . . . . . . 48

IV. Implementation Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

V. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

VI. Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Appendix A. Endangered and Threatened Species Recovery 

Priority Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . 100

Appendix B. Glossary of Technical Terms . . . . . . . . . . . . . . . . . . 101

Appendix C. Summary of Agency and Public Comment on the 

Draft Revised Recovery Plan for the Sihek . . . . . . 103

LIST OF FIGURES 

Page

Figure 1. Location and composition of the Mariana archipelago . . . . . . . . . 3

Figure 2. Territory of Guam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 3. General vegetation of Guam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 4. Annual number of male and female sihek held in captivity . . . . . . 9

Figure 5. Designated sihek critical habitat . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 6. Number of mild and severe typhoons recorded within 10-year 

increments at the U.S. Navy Joint Typhoon Warning Center for 

Guam from 1950 to 1999. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Figure 7. General land ownership on Guam . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 8. Conservation areas in northern Guam, with vegetation types . . . . . 35

Figure 9. Conservation areas in southern Guam, with vegetation types . . . . . 36

 
1

I. BACKGROUND AND OVERVIEW 

A. Introduction 

The Guam Micronesian kingfisher (Halcyon cinnamomina cinnamomina

[also referred to as Todiramphus cinnamominus cinnamominus]), known in 

Chamorro (the native language of Guam) as “sihek,” is endemic to the island of 

Guam. This subspecies is listed as endangered by both the United States under 

the Endangered Species Act (16 United States Code [USC] 1531 et seq.) (U.S. 

Fish and Wildlife Service [USFWS] 1984) and the Territory of Guam (Guam 

Public Law 15-36). Sihek were last observed on Guam in 1988 (Wiles et al.

2003) and are now believed extinct in the wild. Currently, this subspecies is 

represented only by a captive population of 94 individuals in 16 zoological 

institutions in the continental United States and 6 individuals at the Guam 

Division of Aquatic and Wildlife Resources facility on Guam (B. Bahner, pers. 

comm. 2008). Predation by the introduced brown treesnake (Boiga irregularis) 

appears to have been the principal cause of the wild population’s decline and 

extirpation (Savidge 1987). Other factors that may have hastened the decline 

include habitat degradation and loss, competition with the introduced black 

drongo (Dicrurus macrocercus), pesticides, and avian disease. Factors that 

continue to limit the recovery of the species include difficulties with breeding 

sihek in captivity and the continued presence of brown treesnakes on Guam. 

In order to make the most appropriate use of the limited resources 

available for recovery, we, the U.S. Fish and Wildlife Service, assign a recovery 

priority number to each listed species (USFWS 1983a,b). The recovery priority 

number for the sihek is a 6 on a scale of 1 (highest) to 18 (lowest; see Appendix 

A). This priority ranking reflects that the prospects for recovery are relatively 

low, the degree of threats are high, the Guam population is at present formally 

distinguished at the level of a subspecies, and there is no conflict with economic 

development. New molecular techniques suggest the Guam subspecies may 

warrant separate species status (S. Haig, U.S. Geological Survey [USGS], pers. 

comm. 2002), which may shift the ranking of this taxon upward to priority 5. 
2

The sihek has been federally listed as an endangered species since 1984 

(USFWS 1984). A recovery plan for the sihek, which also addressed the Guam 

rail (Gallirallus owstoni), Mariana crow (Corvus kubaryi), Guam broadbill 

(Myiagra freycineti), and Guam bridled white-eye (Zosterops conspicillata 

conspicillata), was approved on September 28, 1990 (USFWS 1990). This 

recovery plan serves as a revision of the 1990 recovery plan for the sihek. A 

revised recovery plan is currently being prepared for the Mariana crow. The 

Guam broadbill was removed from the federal list of threatened and endangered 

species due to extinction on February 23, 2004 (USFWS 2004a). The Guam 

bridled white-eye is also presumed to be extinct. 

B. Guam

Guam is the largest and southernmost island in the Mariana archipelago 

(Figure 1). Guam is approximately 49 kilometers (30 miles) long and 7 to 15 

kilometers (4 to 9 miles) wide with a land area of 550 square kilometers (342 

square miles). The northern half of the island is a relatively flat limestone plateau 

formed over volcanic rock and bounded by steep cliffs (Figure 2). Mountainous 

southern Guam is mostly of volcanic origin with a maximum elevation of 405 

meters (1,330 feet). The approximate boundary between northern and southern 

Guam extends from Hagatna on the west coast of the island to Mangilao on the 

east side. Fringing reefs surround most of the island (Eldredge 1983). 

Guam is an unincorporated territory of the United States. The human 

population was 154,800 in 2000, a 16 percent increase from the 1990 census 

estimate (U.S. Census Bureau 2003). Guam’s climate is tropical and temperatures 

remain warm and relatively consistent during the year, ranging daily from 25

degrees to 30 degrees Celsius (77 to 86 degrees Fahrenheit). Rainfall varies 

considerably among years but averages 218 centimeters (86 inches) annually, 

most of which falls from July to November. A dry season occurs between 

January and May when rains diminish to 8 to 15 centimeters (3 to 6 inches) per 

month. 
3

Figure 1. Location and composition of the Mariana archipelago. Figure 2. Territory of Guam. 
4

200

100

100

Aga Point

Talafofo Bay

Facpi

Point

Orote

Point

Tumon Bay

Andersen

Airforce Base

Philippine Sea

Pacific Ocean

Inarajan

Merizo

Umatac

Talofofo

Agat

Santa

Rita

Apra

Heights

Yona

Asan

Piti

Sinajana

Agana

Tamuning

Mangilao

Barrigada

Yigo

Dededo

Cocos

Island

Apra Harbor

Pati

Point

Ritidian Point

2

0 5 10 2.5 Miles

0 5 10 2.5 Kilometers

Map created by U.S. Fish and Wildlife Service,

Pacific Islands Fish and Wildlife Office, July 2007

Figure 2. Territory of Guam

Elevation - meters

High : 457

Low : 50

100 Meter Contours

Major Roads

Streams
5

In 2002, Donnegan et al. (2004) completed a forest inventory and 

analysis for Guam. They estimated that approximately 48 percent (25,833 

hectares, 63,833 acres) of the island was forested (Figure 3). Of the forested area, 

approximately (17,970 hectares, 44,404 acres) were classified as limestone forest, 

the majority of which was located in northern Guam, and approximately 7,741 

hectares (19,129 acres) were classified as volcanic forest, primarily found in 

southern Guam. Of the remaining lands on Guam (29,068 hectares, 71,827 

acres), 33 percent (17,991 hectares, 44,455 acres) was classified as savanna or 

fernland, 18 percent (9,695 hectares, 23,956 acres) was classified as urban, and 

the remaining 1 percent of the island was either classified as barren lands or water 

or unclassified. For more detailed information about the vegetation on Guam, the 

reader is directed to Fosberg (1960), Stone (1970), and Mueller-Dombois and 

Fosberg (1998). 

C. Species Description and Taxonomy

The sihek is a sexually dimorphic (the sexes are outwardly different in 

appearance) forest kingfisher (Baker 1951). The adult male has a cinnamonbrown head, neck, upper back, and underparts. A black line extends around the 

nape (back of the neck) and the orbital (eye) ring is black. The lower back, lesser 

and underwing coverts, and scapular (shoulder) feathers are greenish-blue and the 

tail is blue. The feet and iris of the eye are dark brown, and the bill is black 

except for some white at the base of the lower mandible. The female resembles 

the adult male, but the upper breast, chin, and throat are paler, and the remaining 

underparts and underwing linings are white instead of cinnamon. Sihek are 

relatively small kingfishers, about 20 centimeters (8 inches) in length (Fry et al.

1992). The weight of 16 wild-caught males ranged from 50.5 to 63.8 grams (1.8 

to 2.6 ounces) (Baker 1951, Jenkins 1983) and the weight of 10 wild-caught 

females ranged from 58.0 to 76.0 grams (2.0 to 2.7 ounces) (Baker 1951). 

Immature birds resemble adults, but the brown of the crown is mixed with 

greenish-blue, the back and wing-coverts are edged with cinnamon, and the chin 

and throat are whitish (Baker 1951). Underparts are buff-white in the immature 

male, but may be paler in the female. 
6

Aga

Point

Talafofo Bay

Facpi

Point

Orote

Point

Tumon Bay

Andersen

Airforce

Base Philippine Sea

Pacific Ocean

Inarajan

Merizo

Umatac

Talofofo

Agat

Santa

Rita

Apra

Heights

Yona

Asan

Piti Sinajana

Agana

Tamuning

Mangilao

Barrigada

Yigo

Dededo

Cocos

Island

Apra

Harbor

Pati

Point

Ritidian

Point

2

0 5 10 2.5 Miles

0 5 10 2.5 Kilometers

Map created by U.S. Fish & Wildlife Service, 

Pacific Islands Fish and Wildlife Office, July 2007

Urban Cultivated

Figure 3. General vegetation of Guam

Urban

Water

Limestone Scrub Forest

Limestone Forest

Ravine Forest

Savanna Complex

Scrub Forest

Wetlands

Plantations
7

The sihek is in the subfamily Daceloninae (tree kingfishers) within the 

family Alcedinidae (kingfishers), order Coraciiformes. It is one of three extant 

subspecies of Halcyon cinnamomina found in Micronesia (Fry et al. 1992). The 

other two subspecies of Micronesian kingfishers -- H. c. reichenbachii and H. c. 

pelewensis -- occur on the islands of Pohnpei (Federated States of Micronesia) 

and Palau (Republic of Palau), respectively. A fourth subspecies, H. c. 

miyakoensis, once occurred on the Ryukyu Islands, but is now extinct (Fry et al.

1992). Recent analyses of mitochondrial DNA suggest that each of these 

subspecies is distinct genetically, perhaps sufficiently so as to merit separate 

species status (S. Haig, pers. comm. 2002). However, further genetic analyses are 

needed. 

Another kingfisher, the mangrove or collared kingfisher (H. chloris), also 

occurs on some of the islands north of Guam in the Mariana archipelago (Rota, 

Aguiguan, Tinian, and Saipan) and the Palau group of islands in Micronesia. The 

collared kingfisher has a blue or green-blue crown, as opposed to the cinnamon 

crown of the sihek, and also has a distinctive small white spot on the forehead just 

forward of the eye. The collared kingfisher is absent from Guam, the native home 

of the Guam Micronesian kingfisher, and also from Pohnpei, but is found on the 

island of Palau along with the Palau Micronesian kingfisher H. c. pelewensis. 

D. Population Trends and Distribution

Historically the sihek occurred throughout Guam in all habitats except 

pure savanna and wetlands (Marshall 1949, Baker 1951, Tubb 1966, Jenkins 

1983). Baker (1951) described the species as “fairly common” in 1945 and 

reported that the sihek was primarily a bird of the forest. Although sihek were 

collected and observed in southern Guam in 1945 by Stophlet (1946) and Baker 

(1948), their numbers decreased sharply over the next two decades. Between 

1963 and 1968 only 2 birds were reported during 56 monthly counts in the Fena 

Lake area, and the sihek was last observed in southern Guam in the 1970s 

(Drahos 1977, 2002). During this decline in southern Guam, sihek were still 

found over much of northern Guam into the late 1970s (Jenkins 1983). In 1981 

the northern Guam population was estimated to be 3,023 birds (Engbring and 
8

Ramsey 1984). This population subsequently declined rapidly, however, and by 

1985 Marshall (1989) reported only 30 sihek in the northern part of the island. 

The species was believed extinct in the wild by 1988 (Wiles et al. 2003). 

Similar patterns of decline were also observed for many of the other native 

forest birds of Guam (Savidge 1987, Wiles et al. 2003). The white-throated 

ground-dove (Gallicolumba xanthonura), Mariana fruit dove (Ptilinopus 

roseicapilla), rufous fantail (Rhipidura rufifrons), Guam broadbill, Guam bridled 

white-eye, and Micronesian honeyeater (Myzomela rubrata) are now extinct on 

Guam. The Mariana crow, Mariana swiftlet (Aerodramus bartschi), and 

Micronesian starling (Aplonis opaca) are still found on Guam but at very low 

numbers (Aguon et al. 2004). The brown treesnake is believed to have been a 

factor in the population decline of each of these species. 

 

In response to the widespread decline of Guam’s native birds, in 1983 the 

American Zoo and Aquarium Association (AZA) initiated the Guam Bird Rescue 

Project and the sihek was identified as a species suited for captive management 

(Hutchins et al. 1996). Between 1984 and 1986, 29 sihek were translocated from 

Guam to several zoos in the mainland United States to start a captive breeding 

program. By 1990, the captive population was up to 61 birds in 12 mainland 

zoological institutions (Figure 4). However, high mortality rates and poor 

reproduction reduced the total annual population size to as low as 50 birds in 1992 

(B. Bahner, Philadelphia Zoo, pers. comm. 2001). For the next several years the 

population hovered between 50 and 55 birds (Figure 4) as high mortality levels 

and poor reproductive success continued to hamper attempts to increase the 

captive population (see Reasons for Decline and Current Threats section, p. 17, 

for details). In 2001, the population grew to 65 individuals and through 2004, 

fluctuated between 57 and 73 birds (B. Bahner, pers. comm., 2004). 

As of May 2008, the population consisted of 60 males, 37 females, and 4 

unsexed chicks distributed among 17 captive propagation institutions in the 

mainland United States and Guam (B. Bahner, pers. comm. 2008 ). Participating 

captive breeding facilities include Disney’s Animal Kingdom; San Diego Wild 

Animal Park; San Diego Zoo; National Zoological Park, the National Zoo’s 

Conservation and Research Center; Brookfield Zoo; Lincoln Park Zoological 
9

Figure 4. Annual number of male and female sihek held in captivity 

(Bahner 1998; B. Bahner, pers. comm. 2005; Bahner and Bier 2007). 

Gardens; St. Louis Zoological Park; Philadelphia Zoological Gardens; Houston 

Zoological Gardens; Milwaukee County Zoological Gardens; Bronx Zoo, and the 

Guam Division of Aquatic and Wildlife Resources. 

E. Life History

1. Behavior 

Sihek make several vocalizations and have often been heard over a 

distance of several hundred meters (Jenkins 1983). A loud rattle-like call is given 

by birds in flight and a shorter version of the rattle-call is given when birds dive 

from perches to capture prey, when paired birds excavate nests, and during 

aggressive interactions. Nestlings also produce a rattle-like call when begging for 

food. A soft scratchy call may be uttered between paired birds in close proximity 

to one another. 

0

10

20

30

40

50

60

1985198619871988198919901991199219931994199519961997199819992000200120022003200420052006

Year

Males Females
10

Observations of paired birds, territorial defense, and cavity excavation 

throughout the year (Jenkins 1983; R. Beck, unpubl. data 1985; J. Marshall and R. 

Beck, unpubl. data 1985) suggest that sihek maintain long-term pair bonds as has 

been documented with marked individuals of the related Pohnpei Micronesian 

kingfisher (H. c. reichenbachii; Kesler and Haig 2007a). Approximately onethird of the territories observed in Pohnpei included a non-breeding helper that 

assisted breeding pairs with territory defense and breeding activities (Kesler and 

Haig 2007a). Cooperative breeding, like that observed on Pohnpei, often occurs 

when habitats are saturated or breeding opportunities are otherwise limited, or 

competition for high-quality territories is intense (Emlen 1982). Although 

cooperative breeding is a relatively rare breeding strategy among birds, it has 

arisen several times in the avian order Coraciiformes to which the Guam 

Micronesian kingfisher belongs (e.g., pied kingfishers [Ceryle rudis], whitefronted bee-eaters [Merops bullockoides], green woodhoopoes [Phoeniculus 

purpureus], and Puerto Rican todies [Todus mexicanus]; Kepler 1972, Stacey and 

Koenig 1990 and references therein). Whether cooperative breeding occurred in 

the Guam subspecies of the Micronesian kingfisher is unknown. 

Sihek are aggressive toward conspecifics (members of the same species) 

as well as individuals of other bird species. Jenkins (1983) observed aggressive 

interactions between male sihek and also between males and females. Sihek have 

been observed harassing flocks of Guam bridled white-eyes (Marshall 1949) and 

Micronesian starlings (Kibler 1950). Such interspecific aggression is probably 

expressed generally, as individuals of most avian species co-occurring with sihek 

give alarm calls when kingfishers are nearby (Jenkins 1983). 

2. Space Use 

Records of distributions and intraspecific territorial behaviors for sihek 

(Jenkins 1983) suggest that the birds maintained exclusive year-round territories. 

In Pohnpei, Micronesian kingfishers actively defend territories from all 

conspecific (same species) intrusions. Territories vary in size with location and 

cover type, but average approximately 10 hectares (25 acres) in the mid-elevation 

zones. During their 6-year study, Kesler and Haig (2007a) also found that 
11

territorial boundaries were stable within and between years, even when breeding 

individuals were replaced and neighboring pairs attempted to intrude. 

3. Reproduction 

Sihek nest in cavities and breeding activity appears to be concentrated 

from December to July (Marshall 1949, Baker 1951, Jenkins 1983). Nests have 

been reported in a variety of trees, including Ficus spp. (banyan), Cocos nucifera

(coconut), Artocarpus spp. (breadfruit), Pisonia grandis (umumu), and 

Tristiropsis obtusangula (faniok) (Baker 1951, Jenkins 1983, Marshall 1989). 

Pairs may excavate their own nests in soft trees, arboreal termitaria (the nests of 

termites [Nasutitermes spp.]), or arboreal fern root masses, or may also utilize 

available natural cavities such as broken tree limbs (Jenkins 1983, Marshall 

1989). Jenkins (1983) observed that some excavated cavities were never used as 

nesting sites, which suggests that the process of excavating nest sites may be 

important in pair-bond formation and maintenance. Cavity excavation precedes 

egg-laying by about a month (Marshall 1989), and on Pohnpei copulations have 

been observed only following bouts of nest excavation (D. Kesler, Oregon State 

University, pers. comm. 2002). Excavation behaviors have also been observed on 

Pohnpei in association with males courting new females (Kesler and Haig 2007a). 

Courtship feeding and vocal duetting (simultaneous calling between members of a 

pair) are common, and presumably function in both pair-bond maintenance and 

territorial maintenance. 

Pohnpei Micronesian kingfishers have been observed to excavate nest 

cavities only in arboreal termite nests (termitaria). These cavities include a 

spherical nest chamber (averaging 18.0 centimeters [7.1 inches] in diameter) and 

an entrance tunnel averaging 10.6 centimeters (4.2 inches) long and 5.1 

centimeters (2.0 inches) in diameter (Kesler and Haig 2005a). Kesler and Haig 

(2005a) found that termitaria used for nesting are higher from the ground and 

larger in volume than unused termitaria. They also found no apparent association 

between nest locations and proximity to foraging areas and forest edge, 

termitarium substrate, or microclimate temperatures. 
12

Both male and female sihek incubate eggs and brood and feed nestlings 

(Jenkins 1983). Eggs are white and reported clutch sizes from wild populations (n 

= 3) were either one or two eggs (Baker 1951, Jenkins 1983, Marshall 1989). 

Clutch sizes of one to three eggs have been reported in the captive population of 

sihek (Bahner et al. 1998). Pohnpei Micronesian kingfishers also appear to lay 

one or two egg clutches (Kesler 2002). Incubation, nestling, and fledgling periods 

for populations of sihek in the wild are unknown. However, incubation and 

nestling periods of captive birds averaged 22 and 33 days, respectively (Bahner et 

al. 1998). In Pohnpei Micronesian kingfishers, incubation lasts 23 to 24 days, 

nestlings fledge 26 to 30 days after hatching, and juveniles remain on their natal 

territories for multiple months and years (Kesler 2002, Kesler and Haig 2007a). 

4. Food Habits 

Sihek feed entirely on animal matter including skinks (Scincidae), geckos 

(Gekkonidae), various insects, segmented worms (Annelida), and hermit crabs 

(Coenobita spp.) (Marshall 1949, Baker 1951, Jenkins 1983). Seale (1901) also 

reported that sihek were known to prey on the chicks of domestic fowl and 

Marshall (1949) noted fish scales in the stomach contents of collected birds. On 

Pohnpei, Micronesian kingfishers have been observed capturing and consuming 

rats (presumably Polynesian rats [Rattus exulans]) and various invertebrates as 

well as chasing and killing chicken chicks (D. Kesler, pers. comm. 2002, 2004). 

Sihek typically forage by perching motionless on exposed branches or 

telephone lines and swooping down to capture prey off the ground with their bill 

(Jenkins 1983). They will also capture prey off nearby foliage and have been 

observed gleaning insects from bark (Maben 1982). Prey items are normally 

manipulated in the bill and beaten against a perch before being swallowed whole 

(Jenkins 1983). 

F. Habitat Requirements 

Little is known about the habitat requirements of the sihek. Jenkins 

(1983) reported that the sihek nested and fed primarily in mature, secondary 
13

growth, and, to a lesser degree, in scrub limestone forest. It was also found in 

coastal strand vegetation containing coconut palm as well as riparian habitat. 

However, Jenkins (1983) reported that it was probably most common along the 

edges of mature limestone forest. Few data exist about specific sihek nest sites in 

the wild, but in one study in northern Guam 16 nest sites were correlated with 

closed canopy cover and dense understory vegetation. In this study, nest cavities 

were excavated in the soft, decaying wood of large, standing dead trees averaging 

43 centimeters (17 inches) in diameter (Marshall 1989). Sihek also appear to 

require diverse vegetative structure capable of providing a wide range of both 

invertebrate and vertebrate prey as well as exposed perches and areas of open 

ground for foraging (USFWS 2002). Good quality sihek habitat would therefore 

provide a combination of both closed canopy forest with large, standing dead 

trees for nesting and areas of open understory or forest edges for foraging 

(Jenkins 1983, Marshall 1989, USFWS 2002). Research on the Pohnpei 

Micronesian kingfisher indicates an area of approximately 8 hectares (20 acres) of 

such habitat may be needed to support at least one pair of kingfishers (Kesler and 

Haig 2007a). However, it should be noted that sihek territories may differ from 

Pohnpei Micronesian kingfisher territories due to differences in forest structure on 

Guam and Pohnpei (Mueller-Dombois and Fosberg 1998). 

Information from extant populations of the closely related Pohnpei and 

Palau Micronesian kingfishers may lend insight into the habitat requirements of 

the Guam birds. Like their Guam counterparts, the Pohnpei Micronesian 

kingfishers are habitat generalists and occur throughout the island in diverse 

habitats including urban developments, coastal mangroves, and dwarf forest 

uplands (Engbring et al. 1990, Buden 2000). Mature rainforest is present 

throughout the island and forms an important component of kingfisher breeding 

territories. Kesler and Haig (2007b) examined 16 territories in Pohnpei, and all 

contained several hectares of rainforest. Kingfisher densities on Pohnpei differ 

across habitats (Engbring et al. 1990; Buden 2000; Kesler and Haig 2007b) with 

the highest densities in mangrove (84 birds per square kilometer [218 birds per 

square mile]) and lowland forests (39 birds per square kilometer [101 birds per 

square mile]), and lower densities in the higher elevations (28 to 31 birds per 

square kilometer [73 to 80 birds per square mile]) (estimates from Engbring et al.

(1990). These differences may reflect different resource distributions among 
14

habitats. Palau Micronesian kingfishers are primarily a forest species (Marshall 

1949; Baker 1951; D. Kesler, pers. comm. 2003). Unlike the Guam and Pohnpei 

subspecies, the kingfishers on Palau coexist with collared kingfishers (H. chloris 

chloris), which are slightly larger and prefer mangrove and lowland forests 

(Marshall 1949; D. Kesler, pers. comm. 2003). 

G. Critical Habitat 

Critical habitat is defined in section 3 of the Endangered Species Act 

as--(i) the specific areas within the geographic area occupied by a species, at the 

time it is listed in accordance with the Act, on which are found those physical or 

biological features (I) essential to the conservation of the species and (II) that may 

require special management considerations or protection; and (ii) specific areas 

outside the geographic area occupied by a species at the time it is listed, upon a 

determination that such areas are essential for the conservation of the species. 

“Conservation” means the use of all methods and procedures that are necessary to 

bring an endangered or a threatened species to the point at which listing under the 

Endangered Species Act is no longer necessary. 

 Critical habitat receives protection under section 7 of the Endangered 

Species Act through the prohibition against destruction or adverse modification of 

critical habitat with regard to actions carried out, funded, or authorized by a 

Federal agency. Section 7 requires consultation on Federal actions that may 

adversely affect critical habitat. 

On October 28, 2004, the U.S. Fish and Wildlife Service designated 152 

hectares (376 acres) of land as critical habitat for the sihek and two other 

endangered species (the Mariana crow and Mariana fruit bat [Pteropus mariannus 

mariannus]) on the fee simple portion of the Guam National Wildlife Refuge in 

northern Guam (Figure 5; USFWS 2004b). Excluded from this designation were 

4,386 hectares (10,838 acres) of Air Force lands, 3,228 hectares (7,977 acres) of 

Navy lands, 1,210 hectares (2,989 acres) of Government of Guam lands, and 785 

hectares (1,941 acres) of private lands in northern and southern Guam that were 

proposed as critical habitat on October 15, 2002 (USFWS 2002). Air Force lands 

were excluded under Section 4(a)(3) of the Endangered Species Act, as amended 
15

2

012 0.5 Miles

012 0.5 Kilometers

Map created by U.S. Fish & 

Wildlife Service, Pacific Islands 

Fish and Wildlife Office, July 2007

Figure 5. Designated sihek critical habitat

Ritidian Point

Andersen Air Force Base

Dededo

Yigo

Sihek or Guam 

Micronesian Kingfisher

Critical Habitat

20 Meter Contours

Major Roads

Guam Micronesian Kingfisher 

Critical Habitat

Communications

Annex

Finnegayan

Andersen Air Force Base

Navy Communications Annex

Parcel boundaries

Pacific Ocean

Philippine

Sea
16

by Section 318 of the fiscal year 2004 National Defense Authorization Act, 

based on the Air Force’s Integrated Natural Resource Management Plan for 

Andersen Air Force Base. Navy lands were excluded under Section 4(b)(2) 

because the benefits of excluding these lands, including benefits to national 

security and existing management plans and conservation efforts, outweighed the 

benefits of designating these lands as critical habitat. Government of Guam lands 

were excluded under Section 4(b)(2) because the benefits of excluding these 

lands, including continued and improved cooperation between Guam and the 

Service and Guam’s natural resource plan, outweigh the benefits of designating 

these lands as critical habitat. Although these lands were excluded from 

designation as critical habitat, they are still considered essential to the 

conservation of the sihek. 

H. Reasons for Decline and Current Threats

In determining whether to list, delist, or reclassify (change from threatened 

to endangered status, or vice versa) a taxon under the Endangered Species Act, we 

evaluate the role of five factors potentially affecting the species. These five 

factors are: 

(A) the present or threatened destruction, modification, or curtailment of its 

habitat or range; 

(B) overutilization for commercial, recreational, scientific, or educational 

purposes; 

(C) disease or predation; 

(D) the inadequacy of existing regulatory mechanisms; and 

(E) other natural or manmade factors affecting its continued existence. 

Assessment of these factors can change within or between captive and wild 

populations and as the status of the taxon changes through time. For example, 

when the sihek was first listed in 1984, disease was believed to be the primary 

threat to the species on Guam (USFWS 1984). Since that time predation by the 

brown treesnake has been identified as the primary threat (Savidge 1987). 

Among the factors that have been hypothesized to threaten the sihek are: 

habitat loss or degradation (factor A), disease (factor C), introduced predators 
17

such as cats (Felis catus), rats (Rattus spp.), monitor lizards (Varanus indicus), 

and brown treesnakes (factor C), human persecution (factor E), contaminants 

(factor E), and competition with and harassment by black drongos (factor E) 

(USFWS 1984, 1990). Of these threats, predation by the brown treesnake is 

believed to have been the overriding cause of the sihek’s decline and extirpation 

on Guam. The primary threats to the current captive population are high mortality 

and low fecundity, which limit population growth and erode genetic diversity, 

although the underlying cause(s) of these threats are unknown. Currently, 

overutilization of sihek for commercial, recreational, scientific, or educational 

purposes (factor B) is not known to be a threat. Existing regulatory mechanisms 

(factor D) do not appear adequate. The sihek is currently listed as endangered by 

the governments of both the United States and Guam. However, the sihek is 

extirpated in the wild and the habitat identified to be essential to its conservation 

has not been fully protected (see Critical Habitat above). 

1. Habitat Degradation and Destruction (Factor A) 

Although little is known about the nature of Guam’s vegetation before 

World War II, progressive alteration of the island’s vegetation clearly began with 

human colonization (Fosberg 1960). On volcanic soils, clearing and burning 

resulted in large expanses of savanna and secondary forest (Mueller-Dombois and 

Fosberg 1998). On limestone soils, native forest was cleared and replaced by 

coconut plantations, open fields and gardens, pasture, and secondary forest 

(Mueller-Dombois and Fosberg 1998). During World War II, large areas were 

cleared and some habitat was destroyed during heavy fighting (Fosberg 1960). 

However, Baker (1946) reported that less than half of Guam had been disturbed 

by American forces during their occupation of the island between 1944 and 1945. 

While large stands of relatively intact native forest can still be found on 

military lands and in the rugged interior areas of northern and southern Guam (see 

Figure 3), some of these areas may be further fragmented and degraded by 

development activities and road building in the coming years (e.g., the Air 

Force’s proposed munitions storage igloo, northwest field beddown, and 

intelligence, surveillance, reconnaissance, and strike capability projects and the 

Department of Defense’s proposal to move an Marine Expeditionary Force to 
18

Guam). Much of the remaining forest has also been severely degraded by 

introduced Philippine deer (Cervus mariannus), feral pigs (Sus scrofa), and feral 

Asiatic water buffalo (Bubalus bubalis), which were introduced to Guam in the 

1600s and 1700s (Conry 1988a, Wiles et al. 1999). These introduced ungulates 

are suspected of significantly impacting native floral communities on Guam by 

consuming seeds, fruits, and foliage, ingesting or trampling seedlings, and 

promoting the spread of introduced weeds (Wiles et al. 1999, Wiles 2005). 

Philippine deer and feral pigs are found throughout Guam. On Andersen Air 

Force Base, densities of Philippine deer and feral pigs were estimated at 1.8 deer 

per hectare (0.8 deer per acre) and 0.4 pigs per hectare (0.2 pigs per acre), which 

are some of the highest densities recorded in the world (Knutson and Vogt, 

unpubl. manuscript 2003). Feral Asiatic water buffalo are found predominantly 

on the Ordnance Annex and surrounding non-Navy lands in southern Guam, 

where the population is estimated to be at least 50-60 animals (A. Brooke, U.S. 

Navy, pers. comm. 2007). 

 Typhoons, a common natural occurrence on Guam (Figure 6), have also 

contributed to the degradation of native forest on Guam. Typhoons can cause 

defoliation (loss of leaves), uprooting of trees, and breakage of stems, branches, 

and trunks of trees depending on the severity and duration of the storm and its 

point of impact (Brokaw and Walker 1991). Donnegan et al. (2004) estimated 20 

percent of the individual trees on Guam have been damaged and that typhoons 

were the primary source of damage for 36 percent of the damaged individuals. 

The impact of typhoons on native forests along with the impacts of feral ungulates 

on regeneration of native species and the spread of invasive plants can work in 

conjunction to further degrade the remaining forests on Guam. 

Sihek may be able to withstand some degree of habitat alteration. Because 

they require open understory forests and forest edges for foraging (Jenkins 1983), 

fragmented and somewhat degraded habitats may provide useful resources for 

birds as long as sufficient patches of mature forest can be found nearby for 

nesting. On Pohnpei, kingfishers do not seem affected by the presence of grazing 

animals, and in fact seem to prefer foraging in areas where a reduction in 
19

0

2

4

6

8

10

12

1950-1959

1960-1969

1970-1979

1980-1989

1990-1999

10-year period

Number of typhoons record

e

Mild

typhoons

Severe

typhoons

Figure 6. Mild and severe typhoons recorded within 10-year increments at the 

U.S. Navy Joint Typhoon Warning Center for Guam from 1950 to 1999. Mild 

typhoons are defined as typhoons with estimated gusts between 80 kph (50 mph) 

and 160 kph (100 mph). Severe typhoons are defined as typhoons with estimated 

gusts above 160 kph (100 mph).

grasses and herbs facilitates the detection of terrestrial skinks (Kesler and Haig 

2007b). Nonetheless, Pohnpei Micronesian kingfishers were found in the highest 

densities in areas without human impacts, such as mangrove forests. 

 2. Avian Disease (Factor C) 

Avian malaria and pox have been important factors in the decline of 

Hawaii’s avifauna (Warner 1968, Van Riper et al. 1986). Although disease was 

not an important factor in the decline of Guam’s forest birds (Savidge et al. 1992), 

a number of avian pathogens have been identified on Guam that could affect the 

recovery of the sihek. Avian mycobacteriosis, a contagious disease caused by the 

bacterial pathogen Mycobacterium avium, has been a significant source of 

mortality in captive sihek (9 of 40 [22.5 percent]) adult deaths) (Junge 1998). 

Silva-Krott et al. (1998) determined that M. avium does exist on Guam, but there 

has never been a recorded case of mortality due to avian mycobacteriosis. 

Savidge et al. (1992) also noted that Salmonella newport, S. waycross, S. 
20

oranienburg, S. amager, Candida tropicalis, Newcastle disease, and influenza 

virus have been reported in native and introduced bird species on Guam. 

Newly emerging diseases, such as West Nile virus and the highly 

pathogenic strain of avian influenza, H5N1, may pose a significant risk to sihek in 

the continental United States and on Guam if it reaches the Pacific rim. As of 

July 2007, H5N1 has not been reported in the western hemisphere or the Mariana 

Islands (National Wildlife Health Center 2007). However, as of May 2007, West 

Nile virus has been detected in 284 bird species, including the related belted 

kingfisher (Ceryle alcyon), from 48 states and the District of Columbia (CDC 

2007). West Nile virus was detected in one sihek that died at the National 

Zoological Park (B. Bahner, pers. comm. 2003); as a result, three sihek at the Park 

were vaccinated (R. Junge, Saint Louis Zoo, pers. comm. 2002). As of May 

2007, RNA (ribonucleic acid) of West Nile virus, the West Nile antigen, or the 

isolated virus had been detected in 62 mosquito species from 10 genera (Aedes, 

Anopheles, Coquillettidia, Culiseta, Culex, Deinocerites, Ochlerotatus, 

Orthopodomyia, Psorophora, and Uranotaenia) in the United States. Three of 

these mosquito genera that are potential carriers of the virus (Aedes, Anopheles, 

and Culex) have been reported in the Mariana Islands (Swezey 1942, Bohart 

1956, Savage et al. 1993). In an effort to prevent the introduction of West Nile 

virus and avian influenza to the island, Guam’s Department of Agriculture 

implemented new testing and quarantine requirements for all avian importations 

(J. Burgett, USFWS, pers. comm. 2007). 

3. Predation by Brown Treesnakes (Factor C) 

 The brown treesnake is native to coastal Australia, Papua New Guinea, 

and a large number of islands in northwestern Melanesia. These snakes are long 

and slender, ranging from 6 grams (0.2 ounces) in weight and a snout-vent length 

of approximately 275 millimeters (11 inches) to 3,000 grams (6.6 pounds) in 

weight and a snout-vent length of approximately 2,700 millimeters (8.75 feet). 

Brown treesnakes are excellent climbers. They are active primarily at night and 

hide during the day in dark crevices and other unexposed areas. They prey on a 

wide variety of animals depending on the size of the individual snake. Brown 

treesnakes in captivity eat only geckos when they are first hatched (F. Qualls and 
21

C. Qualls, USGS/Colorado State University, pers. comm. 2001), but soon add 

skinks to their diet. Skinks form the bulk of the diet for snakes in the body size 

600 to 1,000 millimeters (23 to 39 inches) snout-vent length (Rodda et al. 1999a). 

However, brown treesnakes add birds and mammals to their diet when they 

become reproductively mature (generally at a size of approximately 960 to 1,000 

millimeters [37 to 39 inches] snout-vent length) (Savidge 1988). 

Brown treesnakes probably arrived on Guam prior to 1950 as passive 

stowaways in materiel salvaged from Manus, an island near New Guinea, 

following World War II (Savidge 1987, Rodda et al. 1992). Available evidence 

suggests that brown treesnakes first colonized the Santa Rita/Ordnance Annex 

area, and then spread progressively across the island, reaching the northernmost 

point of the island (Ritidian Point) by 1968 (Savidge 1987). Within 20 years, the 

snake population had reached a peak density of 100 to 120 snakes per hectare (41 

to 50 snakes per acre) on Guam. Such a high density of snakes is one to two 

orders of magnitude higher than would normally be expected for large snakes 

away from the concentrating effects of water or dens (Rodda et al. 1992). 

The only native snake on the island of Guam is a tiny blind snake 

(Ramphotyphlops braminus) that burrows through the soil and feeds on the eggs, 

larvae and pupae of ants and termites. Guam’s native birds were therefore 

particularly vulnerable to the exotic brown treesnake, as they had not evolved 

with any snake as a nest predator. By 1988, the brown treesnake had eliminated 

most of the native birds on the island (Savidge 1987), as well as many other 

native and exotic animal species (Fritts and Rodda 1998). All but two of Guam's 

native bird species (the yellow bittern [Ixobrychus sinensis] and Mariana swiftlet)

have shown patterns of decline coinciding with the expansion of the snake's range 

across the island. These patterns of decline indicated an inverse relationship 

between populations of snakes and birds (Savidge 1987), presumably due to nest 

predation by brown treesnakes. Conry (1988b) recorded daily egg and nestling 

mortality by brown treesnakes as high as 21.5 percent in Philippine turtle-doves 

(Streptopelia bitorquata) on Guam. The sihek’s decline followed the same 

pattern as other forest birds on Guam, having been first extirpated in the southern 

and central portions of the island, where the snake first colonized. The last wild 
22

sihek were observed in 1988 on Andersen Air Force Base in northern Guam 

(Wiles et al. 1995). 

Brown treesnake densities peaked in the mid-1980s and have since 

declined, but remain at levels that threaten efforts to reestablish wild populations 

of sihek on Guam. Without efforts to control brown treesnakes on Guam the 

recovery of the sihek will not be possible. Current evidence suggests that snake 

populations in tangantangan (Leucaena leucocephala) forest on Guam range from 

20 to 60 snakes per hectare (9 to 26 snakes per acre) (counting only larger snakes 

over 800 millimeters [31 inches] snout-vent length). Snakes in this size class 

occur at lower densities (10 to 20 snakes per hectare (4 to 9 snakes per acre) in 

grassland, ravine forest, or native forest vegetation types (Rodda et al. 1999b). 

Historical fluctuations indicate that brown treesnake densities may recover 

following overpredation of its prey base and a crash in available food sources 

(Rodda et al. 1992). A population decline in brown treesnakes across Guam 

between 1985 and 1995 was attributed to limited food availability that resulted 

from the decimation of nearly all native fauna on the island by the brown 

treesnake (Rodda et al. 1992, 1999a; Fritts and Rodda 1998). However, high 

densities of treesnakes persist on Guam due to the continuing availability of 

several species of introduced lizards and rats as potential prey items (McCoid 

1997, Rodda et al. 1999b). Other exotic avian and mammalian prey may also aid 

the snake's survival on Guam. Local residents have reported the loss of many 

domestic birds, as well as some pets, to the nocturnal snake (Fritts and McCoid 

1991). 

The persistence of high densities of brown treesnakes on Guam continues 

to hamper efforts to reestablish sihek populations in the wild. Reestablishing 

sihek on Guam requires successful reproduction in the wild. However, the level 

of brown treesnake predation on sihek eggs and nestlings is expected to be high if 

brown treesnake densities remain high. Therefore, large scale control and/or 

eradication of brown treesnakes on Guam are essential for sihek recovery in the 

wild. 

 
23

4. Other Introduced Predators (Factor C) 

In addition to the brown treesnake, other potential sihek predators found 

on Guam include feral cats, Polynesian rats, roof rats (Rattus rattus), Norway rats 

(R. norvegicus), and monitor lizards. The impact of each of these species on 

sihek is unknown. However, the negative impact of rat (Atkinson 1985, 

Robertson et al. 1994) and cat (Churcher and Lawton 1987) predation on bird 

populations has been well documented and may threaten recovery of the sihek. 

Control of brown treesnake populations could potentially increase predation 

pressure on sihek from these sources as rat and monitor lizard populations would 

undoubtedly increase in response to lower treesnake populations. However, prior 

to the invasion of the brown treesnake, the sihek had managed to maintain high 

population densities even in the presence of these other introduced predators. 

Interestingly, despite the presence of rats and cats on Pohnpei, the only Pohnpei 

Micronesian kingfisher nest predation or destruction observed during 4 years of 

study resulted from humans. Furthermore, aside from the two nests destroyed by 

Pohnpei residents and one nest with non-viable eggs, young apparently fledged 

from every nest observed during the study (n = 35; Kesler and Haig 2007a). This 

extremely high nest success suggests that sihek may not be very susceptible to 

predators other than brown treesnakes. However, the impacts of rats, cats, and 

other introduced predators on sihek have not been determined; therefore, their 

impacts will need to be monitored and managed, if necessary.

5. Human Exploitation and Persecution (Factor E) 

There are no historical problems with hunting or poaching sihek on Guam. 

The harvest of sihek has been outlawed for over a century (Executive Order No. 

61, Naval Governor of Guam, 1903), but they were largely unprotected until 1981 

(Penal Code of Guam 1922, 1947, 1953; Guam Public Law 6-87, 1962; Guam 

Public Law 16-39, 1981). The destruction of nests and persecution of adult 

Micronesian kingfishers by landowners on Pohnpei has been observed (D. Kesler, 

pers. comm. 2002). Engbring et al. (1990) also reported that the Pohnpei 

Micronesian kingfisher is considered a pest species because it is believed to prey 

on small chicks of domestic fowl. 
24

6. Contaminants (Factor E) 

Pesticides have been used extensively in the past for agriculture and 

disease vector control in the Mariana Islands. Following World War II and until 

the early 1970s, DDT (dichlorodiphenyltrichloroethane, an organochlorine 

pesticide now known to have adverse impacts on birds and other wildlife) was 

regularly applied by the military on Guam (Baker 1946, Maben 1980, Anderson 

1981). In addition, Maben (1980) reported that the insecticide malathion, an 

organophosphate, was applied by the military around beaches and buildings up to 

three times a week. Malathion was also aerially applied over approximately a 

third of the island of Guam over 4 days in 1975 to prevent a potential outbreak of 

dengue fever (Haddock et al. 1979). Researchers studying the impacts of 

pesticides on native forest birds in the 1980s did not believe that pesticides played 

a major role in the decline of the sihek and other native forest birds on Guam 

(Grue 1985). However, Drahos (2002) believed that the impact of pesticides on 

native bird populations has been underestimated and that pesticide use may have 

contributed to the initial decline of forest birds on Guam, especially in southern 

Guam. Under current conditions, however, contaminants are not considered a 

threat to the sihek because pesticides, such as DDT and malathion, are no longer 

aerially broadcast on Guam. 

 

7. Competition and Harassment by Black Drongos (Factor E) 

The black drongo (Dicrurus macrocercus), an introduced insectivorous 

bird, is found on the islands of Guam and Rota. They are thought to have been 

intentionally introduced to Rota from Taiwan in 1935 by the Japanese South Seas 

Development Company to control destructive insects (Baker 1948). They were 

first noted on Guam in February 1960 and may have dispersed on their own from 

Rota (Jenkins 1983) or been displaced from Rota by a storm (Drahos 2002). 

Black drongos are common on Guam and can be observed foraging from exposed 

perches in open areas surrounded by disturbed vegetation (Maben 1982). Maben 

(1982) reported harassment of sihek by black drongos and identified the sihek as a 

possible competitor for prey due to similarities between the species in habitat use, 

foraging perches, foraging technique, and prey size. In 2005, black drongos were 

also observed harassing a nesting pair of Mariana crows and an individual 
25

Mariana crow that was recently introduced into the wild in northern Guam (B. 

Dicke, DAWR, pers. comm. 2005). Therefore, harassment by black drongos and 

competition with this introduced bird species could affect sihek recovery, 

especially during the initial stages of the process to reestablish wild populations 

on Guam. 

8. Limited Population Growth in Captivity (Factor E) 

Initial efforts to breed sihek in captivity were successful. However, high 

embryonic, chick, young adult, and adult mortality rates in conjunction with 

limited reproductive success began to plague efforts to increase the captive 

population once it had reached 60 individuals (Hutchins et al. 1996). One 

problem associated with reproductive success has been difficulty in forming 

successful breeding pairs. Fewer than half of the pairs successfully produce 

offspring (Baltz 1998) and the sex ratio has been consistently skewed toward 

males since the late 1980s due to higher levels of female mortality (see Figure 4). 

Poor egg viability and infanticide have also been identified as problems. Of the 

778 eggs produced under captive conditions up to 1997, only 39 percent (301 

eggs) were fertile; 20 percent (159 eggs) were broken, and 41 percent (318 eggs) 

were infertile. Sixty-nine percent of the embryos that died in the shell were 

artificially incubated (Bahner et al. 1998). Seventy-four percent of the parentreared chicks lost prior to fledging disappeared from the nest, either due to 

cannibalism by the parents or other causes. In addition to avian mycobacteriosis 

(22.5 percent of deaths; see Disease, above), other factors that have contributed to 

adult mortality in the captive population include stress, pair aggression, and 

nutritional deficiencies (Hutchins et al. 1996, Bahner et al. 1998). 

 As long as the captive population size remains small, loss of genetic 

diversity will be accelerated. This loss can reduce fitness and evolutionary 

flexibility, and increase the probability of extinction. Since the captive breeding 

program began, one of its main goals has been to maintain or increase genetic 

diversity above 90 percent heterozygosity. However, maintaining genetic 

diversity is difficult due to the inability to pair all individuals, low reproductive 

success, and high mortality rates. The current captive population originated from 

only 17 of the 29 founders brought into captivity (Haig et al. 1995). The 
26

genetically effective population size (Ne) of the captive population is 29.5 and 

the estimated mean inbreeding coefficient (F) is currently 0.023 (Bahner and Bier 

2007). This inbreeding coefficient is expected to rise with time due to the small 

size of the captive population and limited pairing options. Current estimated gene 

diversity is 89.8 percent and is projected to drop to 67 percent gene diversity in 

100 years if the population does not exceed 100 individuals (Bahner and Bier 

2007). 

I. Conservation Efforts 

The 1990 recovery plan for the sihek identified the following six main 

objectives to achieve recovery of the sihek: 

(1) develop a captive breeding program; 

(2) reduce avian mortality in the field; 

(3) provide maximum legal protection for sihek habitat; 

(4) conduct additional research and surveys; 

(5) develop methods for reintroduction; and 

(6) develop a public awareness program. 

Specific recovery actions were identified for each of these objectives. Progress in 

attaining these objectives has been achieved to varying degrees as discussed 

below. 

1. Captive Breeding Program 

Captive breeding of sihek was initiated in 1984 as part of the Guam Bird 

Rescue Project (Hutchins et al. 1996). Twenty-nine sihek were captured in 1984 

(21 birds) and 1986 (8 birds) and transferred to zoos in the continental United 

States for captive breeding (Bahner 1988). The first hand-reared and parentreared chicks were hatched in 1985 (Bahner 1988) and the captive population had 

increased to 61 birds by the end of 1990 (Bahner 1998). Unfortunately, the 

population declined to 48 birds in 1992 and subsequently hovered around 60 birds 

with adult mortalities balanced by juvenile recruitment (Bahner 1993; Hutchins et 

al. 1996; B. Bahner, pers. comm. 2004); populations have increased from 2004 to 

the present. 
27

Currently, the captive propagation program is managed under the 

American Zoo and Aquarium Association’s Species Survival Plan in close 

cooperation with the Guam Division of Aquatic and Wildlife Resources. The 

Species Survival Plan management group consists of a coordinator, 

representatives from each captive breeding institution, two nutrition advisors, a 

veterinary advisor, a pathology advisor, an education advisor, two advisors from 

the population management committee, a Guam representative, and a liaison from 

the U.S. Fish and Wildlife Service. 

Since the captive breeding program began, there have been extensive 

efforts to increase the captive population, maintain genetic diversity, and address 

potential problems with the program (Hutchins et al. 1996, Bahner et al. 1998). 

Studbooks, which provide pedigree data used for demographic and genetic 

analysis, have been published since 1988 (Bahner 1988-1996, 1998, 1999, 2001). 

Formal master planning for the population occurred in 1989, 1993, 2001, and 

2003 to help in long-term planning for the captive population (Bahner 1993, 

Bahner and Lynch 2003). In 1996, an action plan was published which discussed 

many of the problems facing the captive population and provided a guide for 

efforts needed to help increase the population’s size (Hutchins et al. 1996). In 

1998, a husbandry manual was published to standardize procedures among 

participating institutions, provide a review of effective husbandry procedures, and 

facilitate the gathering and exchange of data (Bahner et al. 1998). Consolidation 

of the captive population to fewer institutions and development of a keeper 

training program have also helped to standardize procedures among institutions 

and optimize efforts to increase the population (Hutchins et al. 1996). 

 

In addition to the planning and management efforts above, research has 

been conducted on increasing the captive population and maintaining genetic 

diversity. Marshall (1989) completed research on the basic life history of the wild 

population of sihek which was applied to improve captive breeding efforts. 

Because the sihek is extirpated from the wild, research on the breeding biology 

and life history of Micronesian kingfishers has also been undertaken with the 

Pohnpei subspecies (Kesler 2002; Kesler and Haig 2004, 2005a, 2005b, 2007a, 

2007b). Haig and Ballou (1995) studied the genetic diversity of the captive 
28

population and Haig et al. (1995) studied the genetic relationship among the 

founders of the captive population. Research on the behavioral (Baltz 1998) and 

hormonal aspects (Fowler and McGill 2002) of sihek pairs was undertaken. 

Finally, research continues on the adequacy of sihek diets, pathology, and 

behavior (B. Bahner, pers. comm. 2003). 

Some of the problems associated with the captive propagation efforts on 

the mainland may be related to different climatic conditions relative to the sihek’s 

native Guam, as well as the lack of appropriate nesting logs or natural foods

(Hutchins et al. 1996; Kesler and Haig 2004, 2005b). Breeding sihek on Guam in 

their native climate, with natural nesting substrates and foods available at a 

facility dedicated to sihek propagation, may alleviate some of the factors that have 

hampered the captive breeding efforts thus far. 

In September 2003 three male sihek were transported from the mainland 

to facilities built on Guam and operated by the Guam Division of Aquatic and 

Wildlife Resources. These individuals were transported first to ensure the safety 

of the transfer effort before any of the more valuable breeding females were 

transferred to the island. In April 2004, an additional male and a female sihek 

were transported to facilities on Guam to begin captive breeding efforts on the 

island. In 2005, a total of three clutches were produced resulting in one female 

and two male chicks (S. Medina, pers. comm. 2005). As of February 2007, the 

captive population of sihek on Guam includes four adult males and one male and 

one female juvenile sihek (Bahner and Bier 2007). Two adult female and two 

adult male sihek are scheduled to be transferred to the facility on Guam in late 

2007. 

2. Reduce Avian Mortality in the Field 

Brown treesnake control has been the focus of efforts to reduce avian 

mortality in the field. However, research has also been conducted on the potential 

impacts to wild populations of avian disease (Savidge et al. 1992, Silva-Krott et 

al. 1998), contaminants (Drahos 1975, Grue 1985), and black drongo competition 

(Maben 1982). 
29

a. Brown Treesnake Control 

Since the brown treesnake was identified as a major factor in the decline of 

Guam’s native birdlife (Savidge 1987), extensive research has been initiated to 

develop and implement control methods. Agencies that have committed resources 

to this research include the Department of Interior’s Office of Insular Affairs, the 

Department of Defense, U.S. Department of Agriculture, U.S. Fish and Wildlife 

Service, U.S. Geological Survey, and Guam Division of Aquatic and Wildlife 

Resources. Research has focused on the biology of the brown treesnake, the 

development and testing of control techniques, and the development and testing of 

interdiction techniques (see Reasons for Decline and Current Threats, p. 17). 

Interdiction efforts are focused primarily on preventing the establishment of brown 

treesnakes on islands other than Guam. Because the current goal of this recovery 

plan is to reestablish sihek on Guam, interdiction is not discussed here. Additional 

information on the biology of the brown treesnake and interdiction efforts is 

summarized by Rodda et al. (1999c), and is also available on the websites of the 

U.S. Geological Survey Biological Resources Discipline at 

<http://www.invasivespecies.gov/profiles/bts.shtml> and U.S. Department of 

Agriculture Wildlife Services at <http://www.aphis.usda.gov/ws/btsproj.html>. 

The three most commonly utilized methods for controlling brown 

treesnakes in conservation situations are trapping, exclusion barriers, and snake 

toxicants in experimental situations. Snake traps consist of a cylindrical wire 

mesh body capped on the ends by inward-pointing funnels. A live rodent is 

placed in a snake-proof compartment within the trap to motivate snakes to enter 

(Linnell et al. 1998, Rodda et al. 1999c). Traps can be placed in a wide variety of 

locations and are used for control at both site-specific and landscape levels. Sitespecific applications include trapping around Mariana crow nests, often in 

conjunction with barriers (see below), and around Guam rail and Mariana crow 

captive breeding pens on Guam. Landscape-level trapping includes perimetertrapping experiments in southern Guam and area-trapping experiments in a 42-

hectare (104-acre) portion of the Munitions Storage Area on Andersen Air Force 

Base. All of these applications have reduced snake numbers and benefited 

conservation efforts on Guam. 
30

Snake exclusion barriers are either temporary or permanent structures that 

restrict the movement of snakes. Attempts to protect Mariana crow nests from 

predation using some type of barrier (e.g., Tanglefoot and galvanized steel bands) 

were first attempted in 1988 (Aguon et al. 2002). Of the techniques, an electrical 

barrier was found to be the most effective at protecting nests from predation 

(Aguon et al. 2002) and could also be applied to sihek nesting trees. Bulge, vinyl, 

and masonry barriers were developed specifically for interdiction efforts (Perry et 

al. 1996, 1998, 2001), and only the bulge barrier (fencing constructed with an 

overhang to discourage climbing) has been used for endangered species 

conservation efforts. In 1998 a bulge barrier was retrofitted around a cyclone 

fence around Area 50, a 24-hectare limestone forest area in Northwest Field on 

Andersen Air Force Base. Once the barrier was in place, the area was trapped for 

snakes. Results from this experiment suggest a substantial and sustained 

reduction in snake numbers (Searle and Anderson 1998). However, the fact that 

snake captures continued at a low level throughout the experiment indicates 

leakage through the barrier and/or the presence of untrappable snakes. The 

construction of a test masonry snake barrier around Area 50 and around the 

Munitions Storage Area was also proposed. The results of these experiments 

should determine if trapping and/or toxicant use in conjunction with snake 

barriers is an effective conservation technique. However, the status of these two 

proposed projects is uncertain due to Air Force concerns about the barriers being 

constructed in the blast zone of the Munitions Storage Area on Andersen Air 

Force Base (E. Campbell, U.S. Fish and Wildlife Service, pers. comm. 2004). As 

of September 2008, plans were underway to construct a barrier around an 

alternate site near Potts Junction on Andersen Air Force Base (K. Buermeyer, 

USFWS, PIFWO, pers. comm. 2008). This area was proposed as a mitigation 

area for the Air Force's Northwest Field Beddown Project (U.S. Air Force 2006a)

A variety of toxicants have been tested for their effectiveness at killing brown 

treesnakes by oral ingestion or dermal absorption (Savarie and Bruggers 1999; 

Savarie et al. 2000, 2001). Acetaminophen has been shown to be toxic to brown 

treesnakes in both laboratory and field efficacy trials (Savarie et al. 2001, 

Johnston et al. 2002). In 2002, the Animal and Plant Health Inspection Service 

received a registration under the Federal Insecticide, Fungicide and Rodenticide 

Act (17 USC 136 et seq.) from the U.S. Environmental Protection Agency 
31

allowing the use of dead mice treated with 80 milligrams of acetaminophen to 

control brown treesnakes on Guam and the Northern Mariana Islands. This 

registration allows mice baits to be applied either in bait stations, or by hand and 

aerial broadcast methods. Bait stations are constructed from polyvinyl chloride 

(PVC) tubes 5 to 10 centimeters (2 to 4 inches) in diameter and 30.5 to 46 

centimeters (12 to 18 inches) long and are hung horizontally approximately 1.2 

meters (4 feet) off the ground on trees, fences or other structures. Concerns for 

risk to sihek, Mariana crow and other nontarget species resulted in the 

development of a vertical bait station design; tests of the design (smaller PVC 

tubes open only on one end and hung vertically with the open end down) have 

shown that they deter non-target bird species but may also exclude smaller snakes 

(D. Vice, USDA, Wildlife Services, pers. comm. 2008). Therefore, work on 

alternate designs is being undertaken. 

In addition to the bait stations, aerial bait delivery systems are being 

designed for snakes (Shivik et al. 2002). The dropped baits become entangled in 

the forest canopy, reducing the number landing on the forest floor, thereby 

reducing the number of nontarget species potentially impacted by baits. Hand and 

aerial broadcast application will be beneficial for treating areas such as cliff lines 

or areas of dense forest where the establishment and maintenance of bait stations 

is impractical. The use of acetaminophen-treated bait has enormous potential to 

aid in recovery efforts of endangered vertebrate species on Guam. 

 

Unfortunately, all three of these control techniques have limitations. 

Snake trapping is expensive, and its effectiveness is significantly reduced when 

prey densities are high, when small and/or “trap shy” snakes are present (trials 

show that small snakes are less likely to be captured in traps), and when there is 

immigration from non-control areas (Rodda et al. 1999b). Toxicants, such as 

acetaminophen, appear to also have the same constraints as those encountered by 

snake trapping (size selectivity, likelihood of reduced effectiveness in high prey 

environments, and immigration from adjacent, non-treated areas). Snake barriers 

are relatively costly and may thus be impractical for the long-term protection of 

the large areas needed to recover the Micronesian kingfisher on Guam. 

Hopefully, the limitations of these techniques can be overcome through their 

continued refinement and the development of new control methodologies. 
32

In addition to traps, barriers, and toxicants, research has also been 

conducted on possible biocontrol agents (Nichols 2000, Dobson and Altizer 

2001). An overview of the potential feasibility of biocontrol for brown treesnake 

population suppression has been completed (Dobson and Altizer 2001). This 

document reviews all potential snake pathogens and models potential feasibility 

of generalized biocontrol agents to steer research efforts in directions that yield 

the greatest chance of success. This report is being reviewed and revised by an 

internationally recognized group of vertebrate biocontrol, reptile pathogen, and 

wildlife experts. Efforts have also been made to identify potential paromyxovirus

(Nichols 2000) and haemogregarine parasites (Caudell et al. 2002). However, it 

should be noted that neither of these agents appear to be optimal for the task at 

hand and biocontrol may not yield total eradication. 

b. Other Sources of Avian Mortality 

In addition to work on brown treesnakes, research has been conducted on 

the role of avian disease (Savidge et al. 1992), contaminants (Grue 1985), and 

competition with black drongos (Maben 1982) in the decline of sihek. None of 

these are considered to have been major factors in the extirpation of this species 

from Guam (see Reasons for Decline and Current Threats, p. 17). The potential 

impact of predators other than brown treesnakes on sihek has not been assessed, 

as there was no opportunity to do so before the wild population had gone extinct.

However, continuing research on Pohnpei Micronesian kingfisher population 

dynamics will provide valuable insight into the potential effects of rat and cat 

predation on Guam Micronesian kingfishers. In addition, an effort is underway to 

obtain Environmental Protection Agency registration for use of diphacinone bait 

stations on Guam. Bait stations, and hand and aerial broadcast applications of 

diphacinone, would be useful in controlling rat populations if this should be 

necessary for recovery of the sihek. 
33

3. Habitat Protection 

a. Protected Areas 

Both northern and southern Guam contain large tracts of forested lands 

that have been protected from development, agriculture, and public access since 

World War II as parts of Andersen Air Force Base and Commander of Naval 

Forces in the Mariana Islands (COMNAVMARIANAS [U.S. Navy]). The latter 

includes the Naval Computer and Telecommunications Station in northern Guam, 

and the Waterfront Annex (known as “Big Navy”) and Ordnance Annex in 

southern Guam. Andersen Air Force Base and the Naval Computer and 

Telecommunications Station contain much of the remaining good quality 

limestone forest on northern Guam, while the Ordnance Annex contains the core 

of southern Guam’s forests (Figure 7). 

In 1993, the U.S. Air Force, U.S. Navy, and U.S. Fish and Wildlife 

Service entered into a Memorandum of Understanding to create the Guam 

National Wildlife Refuge. As per the terms of the Memorandum of 

Understanding, the two military branches entered into Cooperative Agreements 

with the U.S. Fish and Wildlife Service in 1994 to designate Department of 

Defense lands as overlay units in the Guam National Wildlife Refuge. Currently 

the Guam National Wildlife Refuge includes 152 hectares (376 acres) of fee 

simple lands and 9,300 hectares (22,980 acres) of overlay lands owned by the 

U.S. Navy and U.S. Air Force (Figures 8 and 9). The primary use of the overlay 

lands is to meet the military mission of national defense and natural resource 

management on these lands, guided by the Integrated Natural Resource 

Management Plans for Andersen Air Force Base and Commander of Naval Forces 

in the Mariana Islands. 

 Within the Guam National Wildlife Refuge overlay lands, there are 

several areas that have been designated by the U.S. Air Force and U.S. Navy for 

special management consideration. Andersen Air Force Base set aside the 281-

hectare (694-acre) Pati Point Natural Area in 1973 (Figure 8), an area that 

contains the primary roost site of the threatened Mariana fruit bat (Pteropus 

mariannus mariannus) on Guam (Wiles et al. 1995), and that also supported sihek 
34

Waterfront Annex

Communications

Annex Finnegayan

Communications

Annex Barrigada

Apra Heights

Santa Rita

Ordnance

Annex

Saja Valley

Facilities

Naval 

Hospital

2

0 5 10 2.5 Miles

0 5 10 2.5 Kilometers

Map created by U.S. Fish & Wildlife Service, 

Pacific Islands Fish and Wildlife Office, July 2007

Figure 7. General land ownership on Guam

Federal - Air Force 100 Meter Contours

Major Roads

Private and Government of Guam

Federal - Guam National Wildlife Refuge

Guam National Wildlife Refuge

Andersen 

Air Force Base

Federal - Navy

Pacific Ocean

Philippine Sea
35

2

012 0.5 Miles

012 0.5 Kilometers

Map created by U.S. Fish & Wildlife Service, 

Pacific Islands Fish and Wildlife Office, July 2007

Figure 8. Conservation areas in northern Guam, with vegetation Types

Urban Cultivated

Urban

Water

Limestone Scrub Forest

Limestone Forest

Ravine Forest

Savanna Complex

Scrub Forest

Wetlands

Plantations

Pacific Ocean

Philippine Sea

Conservation Areas

Government of Guam

Overlay Refuge - Navy

Overlay Refuge - Air Force

Fee Simple Refuge

Vegetation Types

Guam National Wildlife Refuge

Pati Point

Y-Pigua

Conservation

Area

Anao

Conservation

Area

Haputo

Ecological 

Reserve

Dededo
36

Bolanos 

Conservation Area

Cotal

Conservation 

Area

Orote 

Ecological 

Reserve

Facpi

Point

2

012 0.5 Miles

012 0.5 Kilometers

Map created by U.S. Fish & 

Wildlife Service, Pacific Islands

Fish and Wildlife Office, July 2007

Figure 9. Conservation areas in southern Guam, with vegetation types

Urban Cultivated

Urban

Water

Limestone Scrub Forest

Limestone Forest

Ravine Forest

Savanna Complex

Scrub Forest

Wetlands

Plantations

Pacific Ocean

Philippine Sea

Overlay Refuge - Navy

Government of Guam

Conservation Areas Vegetation Types
37

in 1981 (Engbring and Ramsey 1984). In 1985, the U.S. Navy designated the 

131-hectare (324-acre) Haputo Ecological Reserve at the Naval Computer and 

Telecommunications Station (Figure 8) and the 66-hectare (163-acre) Orote 

Ecological Reserve on the Waterfront Annex (Figure 9). Approximately 102 

hectares (252 acres) of the Haputo Ecological Reserve is terrestrial and contains 

forested habitat important to the conservation of the sihek. Approximately 12 

hectares (30 acres) of the Orote Ecological Reserve is terrestrial and contains 

habitat that could be utilized by sihek. However, the forest in this reserve area is 

isolated from other large tracts of forest on Guam. On the Ordnance Annex, the 

Navy has established “No Disturbance” areas with respect to military training 

around Mt. Almagosa (due to the unusual flora surrounding it) and Mahlac Cave 

(due to the presence of the federally endangered Mariana swiftlet colony). These 

areas contain forested habitat important to the conservation of the sihek. For 

additional information about the U.S. Air Force and Navy lands included in the 

overlay refuge see the Integrated Natural Resource Management Plans for 

Andersen Air Force Base (U.S. Air Force 2003) and COMNAVMARIANAS 

(U.S. Navy 2001).

Additionally, the Government of Guam established four reserves (1,700 

hectares [4,200 acres] total) for habitat protection. The Anao and Y-Pigua 

Conservation areas are located in the north (Figure 8), and the Cotal and Bolanos 

Conservation areas in the south (Figure 9). These lands are under the jurisdiction 

of the Chamorro Land Trust Commission of the Government of Guam. The 

Commission has the authority to change the status of these lands to nonconservation areas as they deem appropriate. 

b. Feral Ungulate Management and Removal 

To date, there has been no large-scale control or removal of ungulates in 

northern Guam. Several attempts have been made to completely remove resident 

Philippine deer and feral pigs from Area 50, a 24-hectare (59-acre) patch of 

limestone forest surrounded by a chain-link fence on Andersen Air Force Base, 

but these have been unsuccessful (C. Kessler, U.S. Fish and Wildlife Service, 

pers. comm. 2007). The Air Force is also proposing to fence approximately 254 

hectares (628 acres) to exclude pig and deer and to remove ungulates from these 
38

areas to offset impacts associated with two projects on Andersen Air Force Base 

(U.S. Air Force 2006a, 2006b). In southern Guam, efforts to control Asiatic water 

buffalo on Navy lands have been underway since 1996 and the population has 

been reduced from approximately 300 animals to 50-60 animals (A. Brooke, pers. 

comm. 2007). The Navy has also been working on developing a plan for the 

long-term sustained reduction of pig populations on their lands (A. Brooke, pers. 

comm. 2007). 

4. Public Awareness 

A wide variety of public education and outreach activities has been 

implemented by the Guam Division of Aquatic and Wildlife Resources, focusing 

on the conservation of native species and their biology, and the ecological impacts 

of brown treesnakes. All of these efforts directly or indirectly support sihek 

conservation efforts. Outreach activities include wildlife posters, wildlife 

factsheets, curricula and presentations for school children, occasional appearances 

on radio talk shows, and newspaper articles. In addition to efforts on Guam, 

many of the captive breeding institutions in the mainland United States have 

incorporated information about the decline and conservation of the sihek into their 

exhibits, publications, and outreach programs.
39

II. RECOVERY STRATEGY

The current primary threats to the sihek are limited population growth in 

captivity and the difficulty of reestablishing a population on Guam due to the 

presence of brown treesnakes. However, habitat loss and degradation may 

become a significant issue as the remaining forests on Guam undergo clearing and 

modification due to development, proposed military expansion, and heavy 

browsing pressure from feral ungulate populations. In addition, other threats such 

as disease, and other predators, such as rats, can also affect recovery. Therefore, 

recovery actions are focused on increasing the size of the captive population, 

controlling brown treesnakes, protecting and enhancing habitat for sihek 

conservation, and reintroducing the sihek into the wild on Guam. Establishing a 

captive breeding program on Guam may alleviate some of the reproduction and 

mortality problems that may be associated with environmental factors and nesting 

substrate availability in the captive population in the mainland United States. 

Efforts to increase reproductive success and decrease mortality in captivity will 

continue. Controlling brown treesnakes includes implementing and improving 

existing control techniques in the field and development of new techniques, as 

necessary. Habitat protection and enhancement includes protecting sufficient 

areas of habitat for recovery from development; controlling ungulates, weeds, and 

fires; and replanting degraded areas with native plants, as needed. Currently sihek 

are found only in captivity; therefore, reintroducing them to Guam is essential to 

the recovery of the species. Reestablishing a self-sustaining population in the 

wild will involve developing techniques for successfully releasing sihek, 

identifying optimal locations for release, managing release sites for successful 

reestablishment, and, finally, conducting the release of sihek to the wild. 

Enhancing the captive population, controlling brown treesnakes, 

developing reintroduction techniques, and protecting and enhancing habitat are 

the first steps toward recovery, and each of these actions is currently underway. 

Sihek breeding and holding pens have been constructed on Guam, and five birds 

were transferred there in 2003 and 2004 to start a new captive breeding program 

on the island. Releases of birds into the wild will commence when brown 

treesnake numbers are controlled in suitable habitats. Ideally, sihek releases will 

occur after the captive population has increased and optimal numbers of 
40

individuals are available for release in order to keep the captive population 

viable. However, if efforts to either increase the captive population or control 

brown treesnakes are not successful, it may be necessary to reevaluate the 

recovery strategy for the sihek. Temporary or permanent introduction of a sihek 

population on another island outside the native range of the species, without 

brown treesnakes, may be appropriate to establish a self-sustaining wild 

population with a behavioral repertoire that might be better suited for ultimate 

reintroduction to Guam than that of captive-bred birds. After the sihek becomes 

reestablished on Guam, recovery should be reassessed to determine the steps 

needed for downlisting and then delisting the subspecies. 

Recovery requires that there be at least two viable subpopulations of sihek 

on Guam to reduce the subspecies’ vulnerability to environmental fluctuations 

and catastrophes. At a minimum one subpopulation should occur in northern 

Guam and one in southern Guam. 

A. Recovery Goals, Objectives, and Criteria 

1. Recovery Goals and Objectives 

The primary goals of this recovery plan are to downlist the sihek to 

threatened status and ultimately to remove the sihek from the Federal list of 

threatened and endangered species (delist). These goals will be attained by 

increasing the captive population to a level sufficient to allow reintroductions on 

Guam, reestablishing a wild sihek population on Guam, and establishing and 

maintaining two wild, self-sustaining subpopulations of sihek on Guam. 

2. Recovery Criteria 

The actual downlisting or delisting of a listed entity (i.e., species, 

subspecies, or distinct population segment) is achieved through a formal 

rulemaking process. The recovery criteria set forth in a recovery plan are 

intended to serve as objective, measurable guidelines to assist us in determining 

when a listed entity has recovered to the point that the protections afforded by the 

Endangered Species Act are no longer necessary. However, the actual 
41

downlisting or delisting process is not solely dependent upon achieving the 

recovery criteria; it is achieved through the formal rulemaking process based upon 

a five-factor analysis (per section 4(a)(1) of the Endangered Species Act), in 

conjunction with an analysis of the recovery criteria, that results in a 

determination that the threats to the listed entity have been sufficiently controlled 

or eliminated such that downlisting or delisting is warranted. 

In this revised plan, criteria for downlisting and delisting are based on 

reaching population goals and removing or reducing and controlling threats to the 

sihek. The criteria for downlisting and delisting the sihek incorporate the threats 

of predation by introduced predators and habitat loss. However, new threats to 

the subspecies may arise as recovery efforts continue. These threats will need to 

be monitored and addressed appropriately. If these new threats should become 

significant, the recovery criteria below will need to be revised. 

Reassessment of the recovery criteria may also be appropriate as our 

knowledge regarding the sihek increases over time. As little is currently known 

about sihek population biology, the population goals provided in the criteria are 

based on limited information, including: (1) Micronesian kingfisher population 

estimates and densities from forest bird surveys on Guam (Engbring and Ramsey 

1984), Pohnpei (Engbring et al. 1990), and Palau (Engbring 1992); (2) collared 

kingfisher population estimates and densities from forest bird surveys on Saipan, 

Tinian, and Rota (Engbring et al. 1986); (3) information available on the biology 

of Micronesian kingfishers on Guam and Pohnpei; and (4) vegetation assessments 

for Guam (Donnegan et al. 2004). We estimate that the island of Guam could 

support a population of between 3,600 and 6,800 sihek based on available density 

estimates from Guam and Pohnpei (Engbring and Ramsey 1981, Engbring et al.

1990), territory sizes on Pohnpei (Kesler 2007a), and the availability of potential 

habitat on Guam (Donnegan et al. 2004). However, these population estimates 

may not be necessary to consider the species for delisting. An assessment of 

populations of collared kingfishers, a common species that receives no federal or 

local protection, in the Mariana archipelago indicates that apparently isolated 

populations of 1,300 (e.g., the island of Rota; Todiramphus chloris orii) to 2,300 

(e.g., the closely situated islands of Aguiguan, Tinian, and Saipan combined; T. 

chloris albicilla) collared kingfishers can persist for the foreseeable future without 
42

being threatened with extinction (Engbring et al. 1986). Therefore, we selected 

1,000 adults in northern and southern Guam (2,000 adults total) as a minimum 

population goal for a delisting criterion, in conjunction with efforts to control and 

remove threats to the species, to ensure the population was not likely to become in 

danger of going extinction in the near future. A minimum population of 500 

adults in northern and southern Guam (1,000 adults total) was selected as a 

downlisting criterion, in conjunction with efforts to control and remove threats to 

the species, to ensure that the species was not in immediate danger of going 

extinct. 

These goals should be reevaluated when a wild population is reestablished 

on Guam and more is learned about the population biology of the sihek in its 

native habitat. Likewise, more specific information regarding the quantity of 

sihek habitat needed and levels of brown treesnake control required to achieve the 

population goals set in this plan are not currently known. The criteria addressing 

these threats will thus be subject to refinement as our understanding of sihek 

ecology improves through the implementation of the recovery actions outlined in 

this plan. 

Downlisting Criteria. The sihek may be considered for downlisting from 

endangered to threatened status when all of the following criteria are met: 

Criterion 1: Sihek occur in at least 2 subpopulations (with at least one each in 

northern and southern Guam) of at least 500 adults each; 

Criterion 2: Both subpopulations are either stable or increasing based on 

quantitative surveys or demographic monitoring that demonstrates 

an average intrinsic population growth rate (λ, or lambda) of 

greater than 1.0 over a period of at least 5 consecutive years; 

Criterion 3: Sufficient sihek habitat, based on quantitative estimates of territory 

and home range size, is protected and managed to achieve criteria 

1 and 2 above; and 

Criterion 4: Brown treesnakes and other introduced predators are controlled 
43

over 5 consecutive years at a level sufficient to achieve criteria 1 

and 2 above. 

Delisting Criteria. The sihek may be removed from the Federal list of 

endangered and threatened species when all of the following criteria are met: 

Criterion 1: Sihek occur in at least 2 subpopulations (with at least one each in 

northern and southern Guam) of at least 1,000 adults each; 

Criterion 2: Both subpopulations are either stable or increasing based on 

quantitative surveys or demographic monitoring that demonstrates 

an average intrinsic population growth rate (λ, or lambda) of 

greater than 1.0 over a period of at least 10 consecutive years; 

Criterion 3: Sufficient sihek habitat, based on quantitative estimates of territory 

and home range size, is protected and managed to achieve criteria 

1 and 2 above; and 

Criterion 4: Brown treesnakes and other introduced predators are controlled 

over 10 consecutive years at a level sufficient to achieve criteria 1 

and 2 above. 
44

III. RECOVERY ACTIONS

The goal of this recovery plan is to reestablish a viable population of sihek 

on Guam. Therefore, this plan focuses on the following actions to make this 

possible: 

(1) Coordinate and monitor recovery efforts; 

(2) Restore populations (includes increasing the size of the captive 

population in mainland institutions and on Guam, as well as 

development of a detailed reintroduction program); 

(3) Manage factors affecting population viability (particularly predator 

control); 

(4) Implement a habitat protection and management program; and 

(5) Develop a public awareness program for sihek. 

Due to the limited information available on the Guam subspecies of Micronesian 

kingfisher and the extremely small population available for conservation of the 

subspecies, a few of the actions described below are designed to obtain data from 

the related Pohnpei subspecies or another surrogate species. 

A. Step-Down Outline of Recovery Actions 

1. Coordinate and monitor recovery efforts 

1.1 Maintain an active Recovery Committee 

1.1.1 Coordinate recovery actions with other recovery and 

ecosystem management efforts 

1.1.2 Develop 5-year recovery milestones 

1.1.3 Review recovery efforts annually 

1.2 Monitor recovery efforts 

2. Captive management 

2.1 Continue captive population management efforts in the mainland United 

States 

2.2 Continue to expand the sihek breeding program on Guam 

2.2.1 Continue to maintain sihek breeding and holding pens 

2.2.2 Maintain staffing of facility 

2.2.3 Plan transfer of additional sihek to Guam 

2.3 Increase size of the sihek captive population 
45

2.3.1 Evaluate climate, photoperiod, and reproductive success 

2.3.2 Evaluate nest logs and reproductive success 

2.3.3 Assess effects of nutrition on reproductive success and 

mortality 

2.3.4 Assess effects of age on reproductive success 

2.3.5 Assess effects of hand-rearing on reproductive success 

2.3.6 Develop methods to establish pairs 

2.3.7 Review artificial incubation techniques 

2.3.8 Study chick loss during parent-rearing 

2.3.9 Continue stress hormone research 

2.3.10 Continue to collect and analyze pathology data 

2.3.11 Continue to prevent disease in captive population 

2.3.12 Continue to standardize husbandry techniques and increase 

training 

3. Reintroduce sihek to Guam 

3.1 Develop and test reintroduction strategies to increase likelihood of 

successful releases 

3.1.1 Review other reintroduction programs 

3.1.2 Develop and test reintroduction methods on collared 

kingfishers 

3.2 Determine potential release sites on Guam 

3.2.1 Assess habitat characteristics and potential territory distribution 

3.2.1.1 Obtain/construct Geographic Information System (GIS) 

database of landscape/vegetation characteristics 

3.2.1.2 Evaluate habitat suitability of potential reintroduction 

sites 

3.2.2 Assess historical distribution of sihek 

3.2.3 Assess brown treesnake densities 

3.2.4 Assess food availability 

3.2.5 Assess management potential of release site 

3.3 Work with landowners to develop agreements for sihek release and 

reestablishment 

3.4 Evaluate sihek dispersal, movement, and habitat use 

3.5 Develop a sihek population model 

3.6 Determine number of sihek needed for successful release 
46

3.7 Develop reintroduction plan for sihek 

3.8 Reintroduce sihek to the wild 

3.8.1 Establish a subpopulation in northern Guam 

3.8.2 Establish a subpopulation in southern Guam 

3.9 Assess the need for wild back-up populations outside Guam and 

establish populations as needed. 

3.10 Monitor sihek in the wild 

3.10.1 Gather data on post-release survival of sihek for refining 

release strategies 

3.10.2 Provide long-term monitoring of the sihek population 

3.10.2.1 Update population model (see recovery action 3.5) 

with results from sihek reintroduction efforts 

3.10.2.2 Develop efficient and effective methods for 

monitoring the population 

4. Manage factors affecting wild population viability 

4.1 Control and eradicate brown treesnakes 

4.1.1 Continue and expand brown treesnake control efforts at 

potential reintroduction sites 

4.1.2 Delineate snake-threshold densities using surrogate native 

species 

4.1.3 Refine snake-threshold density estimates for sihek 

4.1.4 Improve existing brown treesnake control measures 

4.1.4.1 Develop effective artificial attractants 

4.1.4.2 Improve trap designs to increase snake capture rate 

4.1.4.3 Develop methods for sequentially controlling or 

eliminating brown treesnakes from large areas inside 

and outside snake exclosures 

4.1.4.4 Develop “kingfisher-safe” acetaminophen bait stations 

4.1.4.5 Develop methods for accurately quantifying brown 

treesnake densities in snake-reduced areas 

4.1.4.6 Develop and test brown treesnake new barrier designs 

4.1.5 Continue to fund research to develop new brown treesnake 

control techniques 

4.2 Monitor direct and indirect impacts of rats on sihek to determine the 

need for rat control 
47

4.3 Assess impact of other sihek predators 

4.4 Prevent accidental or intentional introduction of new predators to 

Guam 

4.5 Assess the need for black drongo control 

4.6 Reduce potential impacts of avian disease on sihek populations 

4.7 Translocate individuals from northern or southern Guam 

subpopulations if necessary 

4.8 Maintain and/or protect reserve habitat on Guam 

4.8.1 Manage the Guam National Wildlife Refuge fee simple and 

overlay refuge lands for sihek conservation 

4.8.2 Manage Government of Guam conservation areas for sihek 

conservation 

4.9 Improve and manage habitat on Guam 

4.9.1 Assess suitability of habitat on Guam 

4.9.2 Develop and implement a sihek habitat management plan 

5. Develop a public awareness program for sihek 

5.1 Fund, support, and promote programs that inform teachers, and that 

educate students, lawmakers, local public and visitors 

5.1.1 Fund and support teacher education programs that promote 

native species conservation 

5.1.1.1 Institute core curriculum programs at the University of 

Guam and community colleges that emphasize native 

species and ecosystem conservation for elementary and 

high school teacher education programs 

5.1.1.2 Develop and distribute educational materials that 

provide teachers with “student-friendly” information 

about native species and ecosystems 

5.1.1.2.1 Work with local teachers to develop lessons 

on native species and ecosystems for use in 

the classroom 

5.1.1.2.2 Make educational materials easily available 

5.1.1.2.3 Update and revise materials 

5.1.2 Create a clearinghouse, such as a website, for information and 

education materials about Guam’s native species 

5.1.3 Continue to provide information and promote awareness of the 
48

harmful effects of alien species, such as the brown treesnake, 

to native species and ecosystems 

5.2 Promote the creation of and support for “Friends” groups, 

partnerships, environmental outreach programs and other support 

groups to provide support for conservation of the sihek and other 

species endemic to Guam 

5.2.1 Recruit, train and support volunteer community leaders to 

organize outreach, native species educational and awareness 

programs at the community level 

5.2.1.1 Support conservation outreach organizations to promote 

conservation at a “grassroots” level 

5.2.1.2 Develop a “mentor” program where natural science 

professionals provide field opportunities for young 

people to learn about Guam’s native species 

5.2.1.3 Support the use of volunteers in projects that will 

contribute to the enhancement of native habitat and 

increase the level of awareness and pride in native 

species within the local populace 

5.2.2 Develop and support partnerships with other conservation 

agencies, local interest groups and private landowners 

B. Narrative Outline of Recovery Actions 

 

1. Coordinate and monitor recovery efforts

Due to the complexity of issues associated with sihek recovery, a coordinated 

recovery effort is needed. Successful recovery will only be feasible through a 

strategy of adaptive management which combines the close cooperation and 

coordination of stakeholders, careful monitoring and evaluations of recovery 

actions, and the prompt resolution of new situations as they arise. 

1.1 Maintain an active Recovery Committee

The recovery committee serves as a forum in which stakeholders 

discuss issues affecting recovery and through which effective and 

coordinated recovery strategies are developed and implemented. As 

defined here, the recovery committee would serve a broader function 

and differs from a recovery team. The committee should include 
49

members with relevant technical expertise, along with 

representatives of agencies, organizations, and landowners that will 

participate in the recovery program. At a minimum, the following 

agencies should be represented and participate actively on the 

committee: U.S. Fish and Wildlife Service; Guam Division of Aquatic 

and Wildlife Resources; participating institutions of the Guam 

Micronesian Kingfisher Species Survival Plan; U.S. Air Force; U.S. 

Navy; U.S. Geological Survey, Biological Research Division; and 

U.S. Department of Agriculture, Wildlife Services. Technical 

disciplines that should be represented on the committee include, but 

are not necessarily limited to: kingfisher biology, brown treesnake 

biology, wildlife biology, population biology, veterinary medicine, 

habitat ecology, avian captive management, and endangered species 

reintroduction. 

1.1.1 Coordinate recovery actions with other recovery and ecosystem 

management efforts 

Due to the similarities in recovery issues for listed species on 

Guam and the Mariana Islands, the recovery committee 

should coordinate with other recovery groups and keep 

abreast of ecosystem management efforts. Disseminating 

meeting minutes and holding concurrent meetings may help 

achieve this goal. 

1.1.2 Develop 5-year recovery milestones

The recovery actions outlined in this revised plan include a 

wide range of activities that will require many years to 

achieve. In order to keep recovery efforts focused and 

properly prioritized, 5-year recovery milestones should be 

developed. 

1.1.3 Review recovery efforts annually

The recovery committee should meet as necessary in order to 

review recovery actions, evaluate new information, establish 

annual research and recovery action plans and priorities, and 

update the 5-year recovery milestones. Important 

information should be disseminated via electronic means to 

all committee members promptly and on a routine basis 
50

between meetings. 

1.2 Monitor recovery efforts

A successful recovery program requires frequent and regular 

monitoring and reporting of recovery efforts. Each recovery action 

includes a monitoring step that will allow review of the efforts to 

determine the most effective recovery methods. 

2. Captive management

Increasing the captive population to sufficient numbers to allow for reintroduction 

to the wild is the first step toward recovery of the sihek. When the captive 

population is increased to a number that is sufficient for supporting a 

reintroduction program, efforts to reintroduce sihek into the wild can be initiated. 

In order to achieve this goal, a captive propagation program, which includes both 

captive propagation efforts on Guam and in zoos on the continental United States, 

is needed. 

2.1 Continue captive population management efforts in the mainland 

United States 

 The sihek captive population is managed by the Micronesian 

Kingfisher SSP to maintain high genetic diversity for the population 

by focusing on equalization of the founder representation, increasing 

population effective size and increasing annual population growth 

rates. These efforts should continue but be modified as necessary to 

maintain a viable captive population while managing the captive 

population to support a reintroduction program. 

2.2 Continue to expand the sihek breeding program on Guam

Some of the problems associated with breeding sihek in mainland 

institutions may be related to the climate, availability of nesting logs 

and natural foods, and limited time and staff to care for sihek 

(Hutchins et al. 1996; Kesler and Haig 2004, 2005b). Continuing 

efforts to breed sihek on Guam may alleviate some of these problems 

and result in an increase in the size of the captive population. 

2.2.1 Continue to maintain sihek breeding and holding pens

Initially, three captive breeding pens and six holding pens were 

built on Guam at the Division of Aquatic and Wildlife 

Resources’ facilities. These pens were built to the 

specifications suggested by other captive rearing facilities and 
51

are snake-proofed and typhoon resistant. These pens should 

be appropriately maintained and as the captive breeding 

program develops, additional breeding, holding and prerelease 

conditioning enclosures should be built as needed. 

2.2.2 Maintain staffing of facility

The captive rearing facility should be sufficiently staffed at all 

times to care for their captive population of sihek. This staff 

should include a supervisory aviculturalist, assistant 

aviculturalist and technicians, and have a qualified veterinarian 

on staff or available on island.

2.2.3 Plan transfer of additional sihek individuals to Guam

In September 2003, three genetically well-represented male 

sihek were transferred to Guam and in April 2004, an 

established pair of sihek was sent to Guam to begin captive 

breeding efforts on Guam. Additional sihek individuals should 

be transferred to Guam as birds and space become available. 

Status reviews of the captive population and transfer 

recommendations should be formulated twice annually until 

recovery is secured. 

2.3 Increase size of the sihek captive population

Recovery of the sihek requires that the captive population be increased 

to sufficient numbers to allow for eventual reintroduction to the wild 

(see Recovery Actions 2.1 and 3.7). Unfortunately, reproductive 

success in the captive population has been limited by difficulty 

forming breeding pairs, infertile eggs, embryonic death, and loss of 

parent-reared chicks shortly after hatching. Mortality in young adult 

and adult sihek has also been high and has been linked to avian disease 

(e.g., avian mycobacteriosis) and may be linked to stress and 

inadequate nutrition. The factors associated with poor reproductive 

success and mortality should be assessed so that propagation 

techniques can be developed or improved to increase reproductive 

success and decrease mortality. 

2.3.1 Evaluate climate, photoperiod, and reproductive success

In many avian species, mating behavior is stimulated by the 

selection and preparation of the nest site. A study is needed to 
52

determine the factors important to the selection of nest logs. 

This will assist managers in providing birds with suitable nest 

sites. 

2.3.2 Evaluate nest logs and reproductive success

For many bird species, reproductive behavior is triggered by 

subtle changes in environmental factors, such as daylight 

regimen, type of lighting, changes in food availability or type, 

and humidity (Hutchins et al. 1995). Data on all of these 

factors should be gathered and analyzed. If appropriate, the 

results should be used to help increase reproductive success. 

2.3.3 Assess effects of nutrition on reproductive success and 

mortality

Captive Micronesian kingfishers have a tendency to become 

obese, which may affect their ability to reproduce (Hutchins et 

al. 1996). In addition, mortality in young adult and adult sihek 

may be related to inadequate nutrition. Data should be 

collected on body weights on all pairs and analyzed to help 

identify the relationship between weight and reproductive 

success. Kingfisher diets in captivity and the wild should also 

be evaluated to determine if the diets used for the captive 

population are sufficient. This information could then be used 

to help optimize sihek diets in captivity. 

2.3.4 Assess effects of age on reproductive success

Age similarities and differences in paired birds are known to 

affect reproductive success (Marzluff and Balda 1988). Data 

should be collected and analyzed to assess the relationship 

between the relative age of paired birds and reproductive 

success. 

2.3.5 Assess effects of hand-rearing on reproductive success

Hand-rearing of sihek was initiated to help improve chick 

survival. However, hand-rearing may affect breeding behavior, 

including the ability of hand-raised birds to raise offspring and 

form pairs (Myers et al. 1988, Hutchins et al. 1995). The 

impact of hand-rearing on the fitness of sihek should be 

assessed as soon as practicable. 
53

2.3.6 Develop methods to establish pairs

Historically, fewer than half of the sihek pairs in captivity have 

produced offspring (Baltz 1998). Allowing birds to select their 

mates is important to establishing a successful pair and 

reproductive success (Yamamoto et al. 1989). However, 

developing the most effective method of introducing male and 

female sihek has been difficult (Baltz 1998). Data on 

introduction techniques and associated behaviors must be 

collected and analyzed to develop an effective technique. 

Standard methods of acclimating, introducing and observing 

sihek pairs will facilitate the identification of reproductively 

compatible pairs to increase breeding success. Recent research 

on kingfisher stress and sex hormones (Fowler and McGill 

2002) may also be helpful in establishing compatible pairs (see 

recovery action 2.3.9). 

2.3.7 Review artificial incubation techniques

About 69 percent of the embryos that died in the shell were 

artificially incubated although only 32 percent of the fertile 

eggs were artificially incubated (Bahner et al. 1998). 

Inappropriate artificial incubation protocols may contribute to 

embryo death (Kuehler and Good 1990). A review of 

techniques is needed to determine the most appropriate 

incubation techniques and parameters. 

2.3.8 Study chick loss during parent-rearing

Of the chicks parent-reared since 1997, about 74 percent 

disappeared from the nest. Possible explanations include 

parental cannibalism; however, that behavior has never been 

observed its potential frequency and the conditions under 

which it may occur are unknown. Time-lapse video studies 

should be used to investigate parental behavior and nestling 

mortality. 

2.3.9 Continue stress hormone research

High stress levels can impact reproductive success. In 

addition, monitoring stress levels could be used to establish 

pairs and evaluate husbandry techniques. Research on 
54

kingfisher stress and sex hormones by Fowler and McGill 

(2002) should continue and be used to modify and develop 

husbandry procedures. 

2.3.10 Continue to collect and analyze pathology data

Data on the causes of young adult and adult mortality should 

continue to be collected and then evaluated to identify potential 

ways of decreasing young adult and adult mortality. 

2.3.11 Continue to prevent disease in captive population

The captive population on the mainland may be exposed to a 

wide variety of avian diseases because they are housed in 

institutions with a large number of avian species. Protocols 

developed in the husbandry manual (Bahner et al. 1998) should 

continue to be followed, improved upon, and updated as 

needed. In addition, research on treatment and prevention of 

avian disease should continue. 

2.3.12 Continue to standardize husbandry techniques and increase 

training

Sources of mortality are easier to identify and prevent if all 

facilities are using similar husbandry techniques. The 

husbandry manual and keeper training program are effective 

means to standardize techniques and share experiences. The 

husbandry manual should continue to be used and its contents 

improved and updated based on controlled experimentation 

(see Recovery Actions 2.3.1 to 2.3.9). The keeper training 

program should also continue and be updated as needed. 

3. Reintroduce sihek to Guam

3.1 Develop and test reintroduction strategies to increase likelihood of 

successful releases

3.1.1 Review other reintroduction programs 

A database has been developed by the Lincoln Park Zoo’s 

Department of Conservation and Science that contains 

information on the methods used in avian reintroductions and 

the results of these reintroduction efforts. This information 

may provide preliminary guidance for developing a 

reintroduction plan for the sihek. 
55

3.1.2 Develop and test reintroduction methods on collared 

kingfishers 

Due to the limited number of sihek and poor success rate of 

reintroduction programs (Griffin et al. 1989), a surrogate 

species such as the collared kingfisher should be used to 

develop and test reintroduction methods for use on sihek. A 

coordinated plan should be developed that includes the release 

of radio-tagged single sex birds (to prevent the establishment 

of a breeding population) and monitoring to determine best 

methods of release, effective release sizes, and number of 

releases. This plan should also include the requirement that all 

released collared kingfishers will be retrieved or sacrificed 

prior to the release of sihek. 

3.2 Determine potential release sites on Guam

Appropriate release sites are important to the success of the 

reintroduction program. These sites should contain the year-round 

requirements of the sihek, allow for predator control and post-release 

monitoring, and be protected for the long-term conservation of the 

sihek. To help determine an appropriate location, a database 

containing information from recovery actions 3.2.1 – 3.2.4 below 

should be developed. 

3.2.1 Assess habitat characteristics and potential territory distribution

In addition to basic habitat requirements, the quality and 

quantity of habitat at the release site will help predict whether 

the reintroduction goal for that location is achievable. 

3.2.1.1 Obtain/construct Geographic Information System (GIS) 

database of landscape/vegetation characteristics

Information about the location and availability of 

landscape resources in Guam is required to design a 

reintroduction plan and to manage reintroduced 

populations. To address this need, a GIS database of 

landscape features, habitat resources, and vegetation 

coverage will be constructed. 

3.2.1.2 Evaluate habitat suitability of potential reintroduction 

sites
56

Resource use and movement models developed for 

Pohnpei Micronesian kingfishers can be used to 

estimate the suitability of proposed reintroduction areas 

using the GIS database described in recovery action 

3.2.1.1. This analysis will provide information about 

the potential number and distribution of sihek territories 

that might be expected on reintroduction areas. 

3.2.2 Assess historical distribution of sihek

Information about the distribution of sihek prior to their 

extirpation from the wild should be used to help determine 

appropriate locations for reintroduction. Published and 

unpublished records and reports, and other resources should be 

searched for information on historical sihek sightings. This 

information should be incorporated into the GIS database of 

landscape/vegetation characteristics (see recovery action 

3.2.1.1). 

3.2.3 Assess brown treesnake densities

The density of brown treesnakes should be determined for a 

particular reintroduction site. Initially this information can be 

obtained from general estimates for different habitat types. 

Site-specific density estimates should be obtained once the 

number of potential sites has been reduced to two or three 

locations. This information can then be used to assess the level 

of snake control needed at the site. 

3.2.4 Assess food availability

The availability of potential food items for sihek should be 

evaluated at potential reintroduction sites prior to release. The 

relative numbers of lizards, small mammals, and invertebrates 

should be assessed at sites on Guam and compared to other 

Micronesian islands that support kingfisher populations, like 

Pohnpei or Rota. 

3.2.5 Assess management potential of release site

Terrain, road access, and land ownership all affect the 

feasibility of managing a release site for sihek reintroduction. 

For example, establishing and maintaining brown treesnake 
57

trap lines through rough terrain is more difficult than along 

established roads and trails. This information should be 

incorporated in the reintroduction site database and used for 

release planning. 

3.3 Work with landowners to develop agreements for sihek release and 

reestablishment

Prior to the release of sihek, agreements (e.g., Memorandum of 

Agreement, Safe Harbor Agreement, and Cooperative Agreement) 

should be developed with landowners for the release and eventual 

reestablishment of sihek on their land. 

3.4 Evaluate kingfisher dispersal, movement, and habitat use

Success of the reintroduction program will rely heavily on 

management efforts such as brown treesnake control at the release site. 

Sihek distribution, movement, and dispersal after the release will 

determine the amount of area and types of habitats requiring 

management. Thus, dispersal, habitat use, and territoriality in 

Micronesian kingfishers should be estimated prior to release using data 

obtained from Pohnpei Micronesian kingfishers. As reintroductions 

occur, data should be obtained on sihek dispersal, habitat use, and 

territoriality. These data would be gathered during short-term and 

long-term monitoring efforts described under recovery action 3.9 

below, and then used in spatially explicit population modeling 

(recovery actions 3.5 and 3.9.2.1) and other planning efforts. 

3.5 Develop a sihek population model 

Population models are useful for evaluating parameters such as 

intrinsic growth rate (lambda) and for gaining insight into how a 

population might respond to proposed management actions. A 

spatially explicit model will be created and maintained to provide a 

tool for planning a sihek release, and to address the need for 

population information in a reintroduced population. The model will 

first be based on demographic data from Pohnpei Micronesian 

kingfishers, and later on spatially explicit demographic data from 

Guam. 

3.6 Determine number of sihek individuals needed for successful release

Other reintroduction programs should be reviewed to help determine 
58

the optimum number of sihek individuals to release. This 

information could be obtained in the reintroduction database described 

under Recovery Action 3.1.1. In addition, because the subspecies is 

currently extinct in the wild, reintroduction will rely on releasing birds 

from the captive population. Therefore, the number of sihek needed to 

sustain the captive population must be maintained before determining 

the number of sihek to release (see Recovery Action 2.1). 

3.7 Develop reintroduction plan for sihek 

After the preliminary reintroduction work has been completed 

(recovery actions 3.1-3.5), a reintroduction plan for sihek should be 

developed based on the completed preliminary work. This plan should 

delineate programmatic goals, transport and release methodologies, 

monitoring and reporting schedules, and evaluation measures. All 

releases should be set up as experiments to test and refine release 

techniques and the relevant aspects of each release (e.g., hard vs. soft; 

microhabitat, dimensions, and location of hacking aviary; and location 

and positioning of supplemental food stations, etc.) must be rigorously 

documented. 

3.8 Reintroduce sihek to the wild

Recovery of the sihek requires the reestablishment of a self-sustaining 

population in the wild. Due to stochastic events such as storms and 

disease outbreaks, at least two subpopulations should be established on 

Guam to prevent extinction and support recovery. The locations of 

reintroduction sites in these regions of Guam will be determined by 

completing recovery action 3.2. In addition, brown treesnakes will be 

controlled at the reintroduction sites through recovery action 4.1. 

3.8.1 Establish a subpopulation in northern Guam

Prior to their extirpation from the wild, the last sihek were 

found in northern Guam. This part of Guam still contains some 

excellent sihek habitat and is currently being managed for the 

Mariana crow reintroduction efforts. 

3.8.2 Establish a subpopulation in southern Guam

Sihek were reported in southern Guam as late as the 1960s. 

Southern Guam currently contains some excellent sihek habitat 

and is large enough to support a subpopulation of sihek. 
59

3.9 Assess the need for wild back-up populations outside Guam and 

establish populations as needed.

It may be necessary to introduce a wild sihek population outside of 

Guam. Such a population might be more viable than one reintroduced 

directly from captivity to Guam because it could be established in 

habitat that has not been compromised by brown treesnakes. It could 

also hedge against the risk of the captive population being lost to 

disease or catastrophe. Moreover, a successful free-living population 

should minimize the progressive loss of behavioral or genetic traits 

(related to, for example, foraging, nesting, and predator avoidance) 

suited to survival in a wild as opposed to captive environment, and 

could thus ultimately improve the likelihood of successful 

reintroduction to Guam. 

Because the sihek is endemic to Guam and all of its native range on 

Guam is now occupied by brown treesnakes, any such introduction of 

back-up populations outside of Guam would be outside the historic 

range of the species. Introduction may be done as an experimental 

population under section 10(j) of the Endangered Species Act, which 

typically is restricted to a species’ probable historic range but can be 

extended beyond this range if “the primary habitat of the species has 

been unsuitably and irreversibly altered or destroyed” [50 CFR 

17.81(a)]. Determination of experimental population status for the 

sihek would parallel that used for the population of Guam rail (Rallus 

owstonii) that was introduced on Rota after the species was extirpated 

on Guam by brown treesnake predation (USFWS 1989). 

 

The appropriateness of the various potential introduction sites outside 

Guam should be evaluated using an approach similar to that outlined 

in recovery action 3.2. The extent and apparent suitability of available 

habitat at each site, as well as the presence of potentially competing 

collared kingfishers, should be considered. The major Mariana Islands 

such as Rota, Saipan, and Tinian have larger areas of habitat, but they 

support substantial human populations, collared kingfishers, and some 

introduced predators, and are either at some risk of accidental brown 
60

treesnake introduction or already support an incipient snake 

population. Some remote northern islands in the Mariana archipelago 

are uninhabited or sparsely inhabited, reducing the likelihood of 

conflict with other uses as well as accidental brown treesnake 

introduction; however, many of these islands have collared kingfisher 

populations and are small or volcanically active, and the logistical 

difficulties of introduction and monitoring activities may be 

substantial. Cooperative opportunities for introduction in the 

Federated States of Micronesia or elsewhere outside United States 

jurisdiction may also be worth considering. 

If an island is determined to be appropriate as an alternate release site, 

the preliminary work and implementation of the introduction plan 

should be completed in a similar manner to that described for Guam 

reintroductions in recovery actions 3.3 through 3.8 above. 

3.10 Monitor sihek in the wild

3.10.1 Gather data on post-release survival of sihek for refining 

release strategies 

Released sihek should be individually marked prior to release 

and intensively monitored after release to determine survival. 

Monitoring efforts should consist of band resighting efforts and 

radio tagging a sample of released birds. Length and intensity 

of the post-release monitoring effort should be based on 

information collected in other release efforts throughout the 

world and modified to meet the needs of the sihek recovery 

program. All data gathered during post-release monitoring 

should be analyzed prior to the next release to refine and 

modify the release strategy. 

3.10.2 Provide long-term monitoring of the sihek population 

The ultimate success of the reintroduction program will depend 

on whether a viable self-sustaining population of sihek is 

established. A long-term monitoring program, which includes 

demographic studies and surveys, will provide the data needed 

to reach this goal effectively and efficiently. 

3.10.2.1 Update population model (see recovery action 3.4) 
61

with results from sihek reintroduction efforts

Updating the population model created in recovery 

action 3.5 with Guam-specific information will improve 

its accuracy and usefulness as a management tool. 

Information gathered based on the populations 

established in recovery action 3.8 will be used to update 

the model. 

3.10.2.2 Develop efficient and effective methods for 

surveying the population

As the wild population increases, the difficulties of 

monitoring individual sihek will increase. Survey 

techniques that accurately estimate the population size 

should be developed and applied consistently 

throughout the remainder of the recovery program. 

4. Manage factors affecting wild population viability

4.1 Control and eradicate brown treesnakes

Controlling brown treesnakes is an important factor in the recovery of 

the sihek. Success will depend either on achieving the complete 

eradication of snakes, or on reducing snake densities to levels at which 

sihek can maintain viable self-sustaining populations. 

4.1.1 Continue and expand brown treesnake control efforts at 

potential reintroduction sites

Brown treesnake control measures are currently being 

undertaken at the Munitions Storage Area. These control 

efforts should continue and be expanded to include larger areas 

that may serve as potential sihek reintroduction sites. 

Techniques that may be utilized include snake trapping, 

acetaminophen bait stations, and aerial broadcast of snake 

toxicants. Due to concerns about the potential ingestion of 

toxicants by sihek, toxicants found harmful to sihek should be 

aerially broadcast prior to reintroduction and bait stations 

should be tested prior to reintroduction (see Recovery Task 

4.1.4.4). 

4.1.2 Delineate snake-threshold densities using surrogate native 

species
62

Reintroduction efforts would be facilitated by determining the 

optimum level of brown treesnake control needed to reduce 

mortality prior to release. This level of control could be 

determined by reestablishing several common native forest bird 

species, such as the Micronesian starling (Aplonis opaca), as 

surrogates for the sihek. Appropriate surrogates should be 

determined based on what is logistically feasible and which 

species’ life history most closely resembles the sihek. 

Estimation of the necessary level of brown treesnake control 

should be determined from the results of well-designed field 

studies and experiments. 

4.1.3 Refine snake-threshold density estimates for sihek

When sihek become established the level of brown treesnake 

control should be modified to best fit the needs of the sihek. 

4.1.4 Improve existing brown treesnake control measures

Existing control measures have several drawbacks that limit 

their efficacy. Efforts to improve existing techniques should 

continue. 

4.1.4.1 Develop effective artificial attractants

Currently, live mice are the most effective attractant for 

luring snakes into snake traps. In addition, dead 

neonatal mice are used as a bait to deliver toxicants to 

snakes. However, small snakes do not normally prey 

on living small mammals until they are larger. In 

addition, it is unknown to what extent small snakes feed 

on dead neonatal mice. The costs of maintaining and 

caring for the live mice are also relatively high. 

Similarly, securing a constant source of dead mice for 

toxicant use may be difficult. Therefore, artificial 

attractants that attract a wide range of snakes would be 

beneficial for control efforts. 

4.1.4.2 Improve trap designs to increase snake capture rate

Current trap designs do not capture all snakes found in 

the population. Therefore, new designs that capture a 

wider range of snake sizes and reduce the number of 
63

untrappable snakes are needed. 

4.1.4.3 Develop methods for sequentially controlling or 

eliminating brown treesnakes from large areas inside 

and outside snake exclosures

Brown treesnake exclosures around large areas can help 

reduce the immigration of snakes into these areas. 

However, large-scale trapping is currently the only 

method available to reduce the densities of snakes 

within these areas. Trapping over large areas can be 

very expensive. Therefore, more efficient methods of 

controlling or eliminating snakes from a site also need 

to be developed. Also, because snake exclosures may 

not be feasible for all areas of Guam, methods for 

efficiently controlling brown treesnake populations 

over large areas outside exclosures are also needed. 

4.1.4.4 Develop “kingfisher-safe” acetaminophen bait stations

The Environmental Protection Agency has registered 

the use of acetaminophen for brown treesnake control. 

However, existing acetaminophen bait station designs 

need to be tested and, if necessary, new designs need to 

be developed that would minimize the take of bait by 

sihek. 

4.1.4.5 Develop methods for accurately quantifying brown 

treesnake densities in snake-reduced areas

Brown treesnake densities are normally determined 

using snake traps. However, as snake densities 

decrease, prey densities increase and reduce the 

probability that brown treesnakes will enter traps. Low 

capture rates limit the ability of existing techniques to 

provide data for obtaining adequately precise 

population estimates. Therefore, alternative methods of 

quantifying densities in snake-reduced areas, such as 

bait take, are needed to assess the effectiveness of 

control efforts. 

4.1.4.6 Develop and test brown treesnake new barrier designs
64

Current barrier designs are expensive or are 

impractical for use in some areas of Guam. Research 

should continue on new barrier designs to improve 

existing barriers and develop less costly, but effective, 

designs. 

4.1.5 Continue to fund research to develop new brown treesnake 

control techniques

The development of new control measures should continue to 

assist with conservation efforts on Guam. These control 

measures include biocontrol, toxicants, and traps. 

4.2 Monitor direct and indirect impacts of rats on sihek to determine the 

need for rat control

The impact of rat predation on sihek is unknown at this time. As 

snake populations are reduced, rat populations will increase. Rats may 

negatively affect sihek directly (i.e., egg and nestling mortality) or 

indirectly (i.e., reductions in food resources). Therefore, rat impacts 

on sihek should be monitored to determine if rat control will be 

necessary. 

4.3 Assess impact of other sihek predators

Little is known about the impact of other introduced predators on sihek 

populations. The level of mortality associated with monitor lizards, 

cats, and other potential predators should be assessed and monitored to 

determine if control efforts are necessary. 

4.4 Prevent accidental or intentional introduction of new predators to 

Guam 

Efforts should be made to prevent the introduction of other potential 

sihek predators to Guam through effective interdiction measures; 

measures may include strengthening the enforcement of importation 

laws. 

4.5 Assess the need for black drongo control

Harassment by and competition with the introduced black drongo 

could affect sihek recovery efforts, especially when sihek populations 

are small. If black drongos are found to be a limiting factor, black 

drongo control measures should be developed and implemented. 

4.6 Reduce potential impacts of avian disease on sihek populations
65

While disease was not found to be a factor in the decline of the sihek, 

diseases represent a serious threat that could adversely affect recovery 

efforts. Appropriate regulatory measures and procedures should be 

adopted to minimize the potential for the introduction of diseases and 

pathogens (e.g., West Nile virus and avian influenza). Disease 

monitoring and control measures should also be initiated as 

appropriate and necessary. 

4.7 Translocate individuals from northern or southern Guam

subpopulations if necessary

Genetic diversity is maintained through the movement of individuals 

among subpopulations. To maintain genetic diversity in the two 

reintroduced sihek subpopulations, at least five individuals should be 

captured and moved from north to south, and from south to north 

biannually. These translocations may cease once there is evidence that 

the birds are naturally dispersing between the two subpopulations. 

4.8 Maintain and/or protect reserve habitat on Guam

Some Federal and Government of Guam lands are already designated 

conservation areas. However, some areas that contain good habitat are 

not included in these protected areas and may be important to the 

conservation of the sihek. In addition, the level of protection among 

conservation areas varies greatly. Adequately protected conservation 

areas need to be managed for the long-term conservation of the sihek. 

Some extant conservation areas and other lands also need to be 

protected and actively managed to assist recovery of the sihek. 

4.8.1 Manage the Guam National Wildlife Refuge fee simple and 

overlay refuge lands for sihek conservation

A Comprehensive Conservation Plan will be developed for the 

Guam National Wildlife Refuge. This plan should include 

programs to manage land on the refuge for the sihek and other 

endangered species. These programs might include fencing 

and ungulate removal, reforestation, predator control, and other 

habitat management. In addition to the refuge conservation 

plan, the overlay refuge is managed through the Integrated 

Natural Resource Management Plans for Air Force and Navy 

lands. These management plans should include programs that 
66

will benefit the conservation of the sihek on overlay lands, 

including reestablishment of sihek by captive release. 

4.8.2 Manage Government of Guam conservation areas for sihek 

conservation

Government of Guam conservation areas include the Anao and 

Y-Pigua Conservation areas in northern Guam (see Figure 8) 

and Cotal and Bolanos Conservation areas in southern Guam 

(see Figure 9). These lands should be designated as permanent 

conservation areas, and actively managed for sihek recovery 

with reforestation, ungulate control, and predator control. 

4.9 Improve and manage habitat on Guam

4.9.1 Assess suitability of habitat on Guam

The quality of potential sihek habitat needs to be assessed to 

determine if vegetation management is necessary. The 

assessment should include feral ungulate damage, availability 

of important foraging and breeding (e.g., Pisonia sp. trees) 

resources for sihek, invasive non-native vegetation, and other 

habitat components important to sihek. 

4.9.2 Develop and implement a sihek habitat management plan

After the suitability of habitat has been assessed, a habitat 

management plan should be developed to assist private, 

Government of Guam, and Federal land managers with 

managing their lands for sihek recovery. This management 

plan should prioritize areas requiring management and provide 

suggestions for appropriate habitat management techniques. 

Examples of habitat management techniques include feral 

ungulate and invasive plant control and reforestation with 

native plant species. 

5. Develop a public awareness program for sihek

Provide information to the general public and lawmakers about Guam’s native 

and endemic species, and their habitats, to create an island-wide conservation 

ethic and to build alliances for conservation on Guam. Public information and 

education play an important role in all recovery programs. With public and 

lawmaker support, the time, costs, and controversy associated with recovery 

actions would be reduced. This support can even persuade lawmakers to 
67

support changes necessary to preserve and protect endangered species and 

their habitats. 

5.1 Fund, support, and promote programs that inform teachers, and that 

educate students, lawmakers, local public and visitors

Raising the level of awareness on endangered species issues at the 

community level is key to the success of the recovery of the sihek. 

Informed teachers will aid in educating the community and lawmakers, 

and with public backing, will support habitat protection and 

endangered species recovery. 

5.1.1 Fund and support teacher education programs that promote 

native species conservation

Teachers provide the basis for educating a large segment of the 

population; therefore educating teachers about endangered 

species issues should be paramount. Providing teachers with 

interesting, appropriate and up-to-date teaching materials for 

classroom use is also an important part of this education 

program. 

5.1.1.1 Institute core curriculum programs at the University 

of Guam and community colleges that emphasize 

native species and ecosystem conservation for 

elementary and high school teacher education 

programs

5.1.1.2 Develop and distribute educational materials that

provide teachers with “student-friendly” information 

about native species and ecosystems

5.1.1.2.1 Work with local teachers to develop 

lessons on native species and ecosystems 

for use in the classroom

Effective education programs require the 

input of educators who will implement 

these programs and who understand the 

needs of their students. Contests or other 

means of obtaining ideas and input from 

local teachers should be pursued. 

5.1.1.2.2 Make educational materials easily 
68

available

Education materials will not be used if 

they are not easily available. One method 

of making materials obtainable and easy to 

update is to make them available for 

downloading from a website (see recovery 

action 5.1.2). Compact disks containing 

education materials could also be cheaply 

produced and easily distributed among 

educators. 

5.1.1.2.3 Update and revise materials

Seek feedback and input from educators 

using the education materials to improve 

the materials. New materials should also 

be produced and old lessons updated 

annually to keep them interesting and 

fresh. This could be facilitated with the 

internet (see recovery action 5.1.2) and 

contests to develop new lessons (see 

recovery action 5.1.1.2.1). 

5.1.2 Create a clearinghouse, such as a website, for information and 

education materials about Guam’s native species

Teachers, students, lawmakers, businesses, conservation 

groups, and the general public should have the most up-to-date 

information available to them. This information can be 

obtained from Federal and territory biologists and the Guam 

Micronesian Kingfisher Species Survival Plan. 

5.1.3 Continue to provide information and promote awareness of the 

harmful effects of alien species, such as the brown treesnake, to 

native species and ecosystems

The brown treesnake is believed to be the leading cause of the 

extinction and endangerment of Guam’s native forest birds. 

However, habitat degradation caused by alien ungulates and 

weeds, predation by introduced rats, and competition and 

harassment by black drongos may have also factored into the 
69

decline. In addition, new species may be introduced that may 

impact the recovery of Guam’s native species. 

5.2 Promote the creation of and support for “Friends” groups, 

partnerships, environmental outreach programs and other support 

groups to provide support for conservation of the sihek and other 

species endemic to Guam

Funding and manpower support for environmental education is often 

in short supply. The establishment of “Friends” groups and 

partnerships helps to fill the shortfalls and need by supplying 

volunteers and funds to maintain these important programs. Many 

refuges and parks rely on these resources to champion new programs 

and maintain old ones at little or no cost. 

5.2.1 Recruit, train and support volunteer community leaders to 

organize outreach, native species educational and awareness 

programs at the community level

5.2.1.1 Support conservation outreach organizations to promote 

conservation at a “grassroots” level

5.2.1.2 Develop a “mentor” program where natural science 

professionals provide field opportunities for young 

people to learn about Guam’s native species

5.2.1.3 Support the use of volunteers in projects that will 

contribute to the enhancement of native habitat and 

increase the level of awareness and pride in native 

species within the local populace

5.2.2 Develop and support partnerships with other conservation 

agencies, local interest groups and private landowners

Protection and rehabilitation of native ecosystems are 

common goals shared among a wide variety of groups and 

individuals in the Mariana Islands. Partnering with other 

groups and individuals to support efforts like reforestation and 

habitat protection can benefit the sihek as well as, for 

example, the coral reef ecosystem and the tourist industry. 
70

IV. IMPLEMENTATION SCHEDULE 

The Implementation Schedule that follows lists and prioritizes the actions 

and estimated costs for the recovery of the sihek. It is a guide for meeting the 

recovery goals outlined in this plan. Recovery actions in the Implementation 

Schedule have been prioritized in a two-tiered ranking system. First, each action 

was assigned a “priority number” from 1 (highest priority) to 3 (lowest priority; 

see definitions below). Second, within each priority number, actions were further 

subdivided and ranked into “priority tiers” from 1 (highest priority) to 3 (lowest 

priority). For example, an action with a priority number of 1 and a priority tier of 

1 has higher priority than an action with a priority number of 1 and a priority tier 

of 2. The numbers in the Action Number column correspond to the descriptions 

of recovery actions in the Narrative Outline of Recovery Actions (p. 48). 

Parties with authority, responsibility, or expressed interest to implement a 

specific recovery action are also identified in the Implementation Schedule. 

When more than one party has been identified the proposed lead party is indicated 

by an asterisk (*). In cases where a lead party has not been identified, each party 

listed is individually responsible for implementing the recovery action. The 

listing of a party in the Implementation Schedule does not require, nor imply a 

requirement, that the identified party has agreed to implement the action(s) or to 

secure funding for implementing the action(s). However, parties willing to 

participate may benefit by being able to show in their own budgets that their 

funding request is for a recovery action identified in an approved recovery plan 

and is therefore considered a necessary action for the overall coordinated effort to 

recover the sihek. Also, section 7(a)(1) of the Endangered Species Act (16 USC 

1531 et seq.) (Act) directs all Federal agencies to utilize their authorities in 

furtherance of the purposes of the Act by carrying out programs for the 

conservation of threatened and endangered species. 

Definition of action priorities: 

• Priority 1: An action that must be taken to prevent extinction or prevent 

the species from declining irreversibly in the foreseeable future. 
71

• Priority 2: An action that must be taken to prevent a significant decline 

in species population or habitat quality, or some other significant negative 

impact short of extinction. 

• Priority 3: All other actions necessary to meet the recovery objectives. 

Definition of action durations: 

• Continuous: An action that will be implemented on a routine basis once 

begun for the period of time estimated to recovery (in this case, 50 years). 

• Ongoing: An action that is currently being implemented and will continue 

until the time estimated to recovery. For the purposes of cost estimation, 

we used our best estimate of the time that may be required to complete the 

action. 

• Unknown: Either action duration or associated costs are not known at this 

time. For the purposes of cost estimation, we used our best estimate of the 

time that may be required to complete the action. 

Threat categories: 

We consider the role of five potential factors affecting the species in order 

to list, delist, or reclassify a taxon. These factors are: 

(A) the present or threatened destruction, modification or curtailment of its 

habitat or range; 

(B) overutilization for commercial, recreational, scientific, or educational 

purposes; 

(C) disease or predation, 

(D) the inadequacy of existing regulatory mechanisms; 

(E) other natural or manmade factors affecting its continued existence. 

Recovery actions are designed to address the threats in the Listing Factor 

column in order to meet the recovery criteria of creating two viable, stable 

subpopulations on Guam, predator control, and management of habitat needed for 

recovery (see Recovery Criteria section). The majority of the recovery actions in 

this plan address the brown treesnake threat (factor C), habitat loss (factor A), and 

limited population growth (factor E). 
72

Responsible Parties for Action Implementation: 

We have statutory responsibility for implementing this recovery plan. 

Only Federal agencies are mandated to take part in the effort under section 7(a)(1) 

of the Act (16 USC 1531 et seq.). However, species recovery will require the 

involvement of the full range of Federal, territorial, private, and local interests. 

The expertise and contributions of additional agencies and interested parties will 

be needed to implement recovery actions and to accomplish education and 

outreach objectives. For each recovery action described in the Implementation 

Schedule, the column titled “Responsible Parties” lists the primary Federal and 

local agencies we have identified as having the authority and responsibility for 

implementing recovery actions and other groups, partners, and partnerships who 

are actively involved in recovery. 
73

Key to Acronyms used in the Implementation Schedule: 

• BRD: United States Geological Survey, Biological Research Discipline 

• DAWR: Guam Division of Aquatic and Wildlife Resources 

• GNWR: Guam National Wildlife Refuge 

• MKRC: Guam Micronesian Kingfisher Recovery Committee 

• SSP: American Zoo and Aquarium Association’s Species Survival Plan 

• USAF: United States Air Force 

• USFWS: United States Fish and Wildlife Service 

• USN: United States Navy 

• WS: United States Department of Agriculture, Wildlife Services 

Cost estimates: 

The costs of implementing the identified recovery actions are estimated over 

two timeframes: the first 5 years covered by this recovery plan (5-Year Costs 

column) and the total costs of recovery for the 50-year period that may be 

required to fully recover the sihek (Total Costs column).
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

74

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

1 2.1 E Continue captive 

population management efforts 

15 years SSP*, 

DAWR 

15 1 1 1 1 1 5 

1 2.2.1 E Continue to maintain 

sihek breeding and holding pens on Guam 

Continuous DAWR 50 10 1 1 10 1 23 

1 2.3.3 E Plan transfers of 

additional sihek to Guam 

15 years SSP*, 

DAWR 

15 1 1 1 1 1 5 

1 2.3.11 E Continue to prevent 

disease in captive population 

15 years SSP 15 1 1 1 1 1 5 

1 3.8.1 C,E Reintroduce sihek to 

northern Guam 

10 years USFWS, 

DAWR* 

200 - - - - 20 20 

2 4.1.1 C Continue and expand 

efforts to reduce snake populations at reintroduction sites 

Ongoing WS*, 

DAWR 

11,000 500 500 500 500 500 2,500 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

75

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

2 2.2.2 E Maintain staffing of 

Guam facility 

20 years DAWR 120 6 6 6 6 6 30 

2 2.3.1 E Evaluate climate, 

photoperiod, and reproductive success and modify captive management, as appropriate 

2 years SSP 10 5 5 - - - 10 

2 2.3.2 E Evaluate nest logs and 

reproductive success and modify captive management, as appropriate 

2 years SSP*, 

DAWR 

10 5 5 - - - 10 

2 2.3.3 E Assess effects of 

nutrition on reproductive success and modify captive management as appropriate 

2 years SSP 10 5 5 - - - 10 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

76

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

2 2.3.4 E Assess effects of age 

on reproductive success and modify captive management, as appropriate 

2 years SSP 10 5 5 - - - 10 

2 2.3.5 E Assess effects of 

hand-rearing on reproductive success, and modify management, as appropriate 

2 years SSP 10 5 5 - - - 10 

2 2.3.6 E Develop methods to 

establish pairs and implement, as appropriate 

Ongoing; 5 years 

SSP*, DAWR 

15 3 3 3 3 3 15 

2 2.3.7 E Review artificial 

incubation techniques and modify management, as appropriate 

2 years SSP 10 5 5 - - - 10 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

77

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

2 2.3.8 E Study chick loss 

during parent-rearing and modify management, as appropriate 

2 years SSP 10 5 5 - - - 10 

2 2.3.9 E Continue stress 

hormone research and incorporate results in management, as appropriate 

2 years SSP 10 5 5 - - - 10 

2 2.3.10 E Collect and analyze 

pathology data and modify management, as appropriate 

5 years SSP 10 2 2 2 2 2 10 

2 2.3.12 E Continue to 

standardize husbandry techniques and training 

15 years SSP 15 1 1 1 1 1 5 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

78

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

2 4.1.4.3 C Develop methods for 

controlling or eliminating brown treesnakes inside & outside exclosures to support reintroduction 

2 years BRD, WS 40 20 20 - - - 40 

2 4.1.4.4 C Develop “kingfisher 

safe” acetaminophen bait stations to support snake control efforts 

2 years WS 20 10 10 - - - 20 

2 3.1.1 E Review other 

reintroduction programs 

1 year USFWS, 

DAWR* 

3 3 - - - - 3 

2 3.1.2 E Develop and test 

reintroduction methods on collared kingfishers 

2 years USFWS 40 20 20 - - - 40 

2 3.2 E Determine locations 

of potential release sites on Guam 

1 year USFWS, 

DAWR* 

1 1 - - - - 1 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

79

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

2 3.2.1.1 E Obtain/construct GIS 

of Guam landscape/vegetation characteristics to support reintroduction planning 

1 year USFWS 5 5 - - - - 5 

2 3.2.1.2 E Evaluate suitability of 

potential reintroduction sites 

1 year USFWS*, 

BRD 

20 20 - - - - 20 

2 3.2.2 E Assess historical 

distribution of sihek to support reintroduction planning 

1 year USFWS 1 1 - - - - 1 

2 3.2.3 C Assess brown 

treesnake densities to support reintroduction planning 

1 year USFWS*, 

DAWR, BRD 

20 20 - - - - 20 

2 3.2.4 A,C Assess food 

availability to support reintroduction planning 

1 year USFWS*, 

DAWR 

2 2 - - - - 2 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

80

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

2 3.2.5 C,E Assess management 

potential of release site 

1 year USFWS*, 

DAWR, WS 

2 2 - - - - 2 

2 3.3 E Work with 

landowners to develop agreements for sihek release and reestablishment 

2 years USFWS 4 2 2 - - - 4 

2 3.6 C,E Determine number of 

sihek needed for successful release 

1 year USFWS, 

DAWR* 

5 5 - - - - 5 

2 3.7 E Develop 

reintroduction plan for sihek 

1 year USFWS, 

DAWR* 

5 - - - - 5 5 

2 3.9 C, E Assess the need for 

wild backup populations outside Guam and establish populations as needed 

TBD USFWS, 

DAWR* 

TBD 

2 3.10.1 A,C,E Gather data on postrelease survival of 

sihek 

4 years USFWS, 

DAWR* 

40 - - - - 10 10 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

81

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

2 4.1.2 C Delineate snakethreshold densities 

using surrogate native species 

4 years USFWS*, 

BRD 

100 30 30 20 20 - 100 

2 4.1.3 C Refine snakethreshold density 

estimates for sihek 

4 years USFWS, 

BRD* 

40 - - - - 10 10 

2 4.1.4.1 C Develop effective 

artificial attractants for snakes to support reintroduction efforts 

2 years BRD, WS* 20 10 10 - - - 20 

2 4.1.4.2 C Improve trap designs 

to increase snake capture rate to support reintroduction efforts 

2 years BRD*, WS 20 10 10 - - - 20 

2 4.1.4.5 C Develop methods for 

quantifying brown treesnake densities in snake-reduced areas 

2 years BRD 40 20 20 - - - 40 

2 4.1.4.6 C Develop and test new 

snake barrier designs 

3 years BRD 30 10 10 10 - - 30 

2 4.1.5 C Continue to fund 10 years USFWS*, 100 10 10 10 10 10 50 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

82

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

research to develop new snake control techniques 

USAF, USN 

2 4.6 C Reduce potential 

impacts of avian disease on sihek populations 

Continuous USFWS*, 

DAWR, WS 

50 1 1 1 1 1 5 

2 4.4 C Prevent accidental or 

intentional introduction of new avian predators to Guam 

Continuous DAWR*, 

USFWS 

50 1 1 1 1 1 5 

2 4.8.1 A Manage the Guam 

National Wildlife Refuge fee simple and overlay lands for sihek conservation 

Ongoing USFWS*, 

USAF, USN 

500 50 50 50 50 50 250 

2 4.8.2 A Manage and protect 

Government of Guam Conservation Areas for sihek conservation 

10 years DAWR 500 50 50 50 50 50 250 

2 4.9.1 A Assess suitability of 2 years USFWS*, 40 20 20 - - - 40 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

83

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

sihek habitat on Guam USAF, USN, 

DAWR 

2 4.9.2 A Develop and 

implement habitat management plan 

20 years USFWS*, 

USAF, USN, DAWR 

405 - - 5 20 20 45 

3 1.1 NA Maintain an active 

Recovery Committee 

Ongoing USFWS 50 1 1 1 1 1 5 

3 1.1.1 NA Coordinate recovery 

actions with other conservation efforts 

Ongoing USFWS 50 1 1 1 1 1 5 

3 1.1.2 NA Develop 5-year 

recovery milestones 

Continuous, as needed 

USFWS*, MKRC 

10 1 - - - - 1 

3 1.1.3 NA Review recovery 

efforts annually 

Continuous USFWS*, 

MKRC 

50 1 1 1 1 1 5 

3 1.2 NA Monitor recovery 

efforts 

Ongoing USFWS 50 1 1 1 1 1 5 

3 3.4 C,E Evaluate sihek 

dispersal, movement and habitat use 

4 years, minimum 

USFWS*, DAWR 

40 - - - - 10 10 

3 3.5 C,E Develop a population 

model 

1 year USFWS 10 10 - - - - 10 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

84

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

3 3.8.2 C,E Reintroduce sihek to 

establish a subpopulation in southern Guam 

20 years USFWS, 

DAWR* 

200 - - - - - 0 

3 3.10.2.2 A,B,C,

D,E 

Develop efficient survey methods 

1 year USFWS, 

DAWR* 

10 - - - - 10 10 

3 3.10.2.1 A,B,C,

D,E 

Update population model (see 3.4) with results from sihek reintroduction 

4 years USFWS*, 

DAWR 

40 - - - - 10 10 

3 4.2 C Monitor direct and 

indirect impacts of rats on sihek to determine the need for rat control 

2 years, minimum 

USFWS, DAWR* 

20 - - - - 10 10 

3 4.3 C Assess impact of other 

sihek predators 

2 years, Minimum 

USFWS, DAWR* 

20 - - - - 10 10 

3 4.5 E Assess the need for 

black drongo control 

2 years, minimum 

USFWS, DAWR* 

20 - - - - 10 10 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

85

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

3 5.1.1.1 A,B,C,

D,E 

Institute curriculum programs for elementary & high school teachers 

10 years USFWS*, 

DAWR 

50 5 5 5 5 5 25 

3 5.1.1.2.1 A,B,C,

D,E 

Work with local teachers to develop lessons on native species and ecosystems 

Unknown USFWS*, 

DAWR 

50 5 - - - - 5 

3 5.1.1.2.2 A,B,C,

D,E 

Make educational materials easily available 

Unknown; as needed 

USFWS*, DAWR 

25 1 - 1 - 1 3 

3 5.1.1.2.3 A,B,C,

D,E 

Update and revise materials 

Unknown; as needed 

USFWS*, DAWR 

50 5 - - - - 5 

3 5.1.2 A,B,C,

D,E 

Create a clearinghouse for information and education materials about Guam’s native species 

10 years USFWS*, 

DAWR 

10 1 1 1 1 1 5 
Implementation Schedule for the Revised Recovery Plan for the Guam Micronesian Kingfisher 

86

Cost Estimate (in $10,000 units) 

Priority Number 

Action Number 

Listing Factor 

Action Description 

Action Duration 

Responsible Parties 

Total 

Costs 

FY 

08 

FY 

09 

FY 

10 

FY 

11 

FY 

12 

5-Year 

Costs 

3 5.1.3 A,B,C,

D,E 

Continue to provide information and promote awareness of the harmful effects of alien species to native species and ecosystems 

Continuous USFWS*, 

DAWR 

50 1 1 1 1 1 5 

3 5.2.1.1 A,B,C,

D,E 

Support conservation outreach organizations to promote conservation at a “grassroots” level 

20 years USFWS*, 

DAWR 

20 1 1 1 1 1 5 

3 5.2.1.2 A,B,C,

D,E 

Develop a “mentor” program . . . 

10 years USFWS*, 

DAWR 

50 5 5 5 5 5 25 

3 5.2.1.3 A,B,C,

D,E 

Support the use of volunteers . . . 

Continuous USFWS*, 

DAWR 

50 1 1 1 1 1 5 

3 5.2.2 A,B,C,

D,E 

Develop and support partnerships 

20 years USFWS*, 

DAWR 

20 1 1 1 1 1 5 

TOTALS 14,583 3,920 
87

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Rodda, G. H., M. J. McCoid, T. H. Fritts, and E. W. Campbell, III. 1999b. 

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253 in Problem snake management: the habu and the brown treesnake (G. 

H. Rodda, Y. Sawai, D. Chiszar, and H. Tanaka, editors). Cornell 

University Press, Ithaca, New York. 534 pp. 

Rodda, G. H., T. H. Fritts, C. S. Clark, S. W. Gotte, and and D. Chizar. 1999c. A 

state-of-the art trap for the brown treesnake. Pages 268-284 in Problem 

snake management: the habu and the brown treesnake (G. H. Rodda, Y. 

Sawai, D. Chiszar, and H. Tanaka, editors). Cornell University Press, 

Ithaca, New York. 534 pp. 

Savage, H. M., C. J. Mitchell, M. Roppul, L. T. Castro, R. L. Kepple, and S. P. 

Flood. 1993. Mosquito faunal survey of Saipan, Mariana Islands 
97

(Diptera: Culicidae): taxonomy and larval ecology. Mosquito 

Systematics 25:17-24. 

Savarie, P. J., and R. L. Bruggers. 1999. Candidate repellents, oral and dermal 

toxicants, and fumigants for brown treesnake control. Pages 417-422, in

Problem snake management: the habu and the brown treesnake (G. H. 

Rodda, Y. Sawai, D. Chiszar, and H. Tanaka, editors). Cornell University 

Press, Ithaca, New York. 534 pp. 

Savarie, P. J., D. L. York, J. C. Hurley, S. Volz, and J. E. Brooks. 2000. Testing 

the dermal and oral toxicity of selected chemicals to Brown Treesnakes. 

Pages 139-145 in Volume 19, Proceedings of the 19th Vertebrate Pest 

Conference (T. P. Salmon and A. C. Crabb, editors). University of 

California, Davis; Davis, California. 

Savarie, P. J., J. A. Shivik, G. C. White, J. C. Hurley, and L. Clark. 2001. Use of 

acetaminophen for large scale control of Brown Treesnakes. Journal of 

Wildlife Management 65:356-365. 

Savidge, J. A. 1987. Extinction of an island avifauna by an introduced snake. 

Ecology 68:660-668. 

Savidge, J. A. 1988. Food habits of Boiga irregularis, an introduced predator on 

Guam. Journal of Herpetology 22:275-282. 

Savidge, J. A., L. Sileo, and L. M. Siegfried. 1992. Was disease involved in the 

decimation of Guam’s avifauna? Journal of Wildlife Diseases 28:206-214. 

Seale, A. 1901. Report of a mission to Guam. Honolulu: Occasional papers of 

the Bernice P. Bishop Museum 1:17-128. 

Searle, A. D. and R. D. Anderson. 1998. Establishment of populations of 

endangered species in snake-free areas on Guam. Pages 160-178 in

Annual Report Fiscal Year 1998. Division of Aquatic and Wildlife 

Resources, Guam Department of Agriculture, Mangilao, Guam. 
98

Shivik, J. A., P. J. Savarie, and L. Clark. 2002. Aerial delivery of baits to brown 

treesnakes. Wildlife Society Bulletin 30:1062-1067. 

Silva-Krott, I., M. K. Brock, and R. E. Junge. 1998. Determination of the 

presence of Mycobacterium avium on Guam as precursor to reintroduction 

of indigenous bird species. Pacific Conservation Biology 4:227-231. 

Stacey, P.B., and W.D, Koenig. 1990. Cooperative breeding in birds: Long-term 

studies of ecology and behavior. Cambridge University Press, Cambridge. 

633 pages. 

Stone, B. C. 1970. The flora of Guam. Micronesica 6:1-659. 

Stophlet, J. J. 1946. Birds of Guam. Auk 63:534-541. 

Swezey, O. H. 1942. Insects of Guam – 1. Culicidae of Guam. Bernice P. Bishop 

Museum Bulletin 172:199-200. 

Tubb, H. A. 1966. Notes on birds of Guam. Natural History Bulletin of the Siam 

Society 21:135-138. 

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Base, Guam. 

U.S. Air Force. 2006a. Draft Environmental Assessment: Beddown of Training 

and Support Initiatives at Northwest Field, Andersen Air Force Base, Guam, 

March 2006. Department of the Air Force, Pacific Air Forces, Hickam Air 

Force Base, Hawaii. 241 pp. 

U.S. Air Force. 2006b. Draft Environmental Impact Statement: Establishment 

and Operation of an Intelligence, Surveillance, and Reconnaissance, and 

Strike Capability, Andersen Air Force Base, Guam, April 2006. Department 
99

of the Air Force, Pacific Air Forces, Hickam Air Force Base, Hawaii. 309 

pp. 

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at <http://www.census.gov>. 

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species listing and recovery priority guidance. Federal Register 48:43098-

43105. September 21, 1983. 

[USFWS] U.S. Fish and Wildlife Service. 1983b. Endangered and threatened 

species listing and recovery priority guidelines correction. Federal 

Register 48:51985. November 15, 1983. 

[USFWS] U.S. Fish and Wildlife Service. 1984. Endangered and threatened 

wildlife and plants; Determination of endangered species status for seven 

birds and two bats of Guam and the Northern Mariana Islands. Federal 

Register 49:33881-33885. August 27, 1984. 

[USFWS] U.S. Fish and Wildlife Service. 1989. Endangered and threatened 

wildlife and plants: Determination of experimental population status for 

an introduced population of Guam rails on Rota in the Commonwealth of 

the Northern Mariana Islands. Federal Register 54:43966-43970. October 

30, 1989. 

[USFWS] U.S. Fish and Wildlife Service. 1990. Native forest birds of Guam and 

Rota of the Commonwealth of the Northern Mariana Islands Recovery 

Plan. U.S. Fish and Wildlife Service, Portland, Oregon. 86pp. 

[USFWS] U.S. Fish and Wildlife Service. 2002. Endangered and threatened 

wildlife and plants; Determinations of prudency for two mammal and four 

bird species in Guam and the Commonwealth of the Northern Mariana 

Islands and proposed designations of critical habitat for one mammal and 

two bird species; proposed rule. Federal Register 67:63738-63772. 

October 15, 2002. 
100

[USFWS] U.S. Fish and Wildlife Service. 2004a. Endangered and threatened 

wildlife and plants; Removing the Mariana mallard and the Guam 

broadbill from the federal list of endangered and threatened wildlife; final 

rule. Federal Register 69:8116-8119. February 23, 2004. 

[USFWS] U.S. Fish and Wildlife Service. 2004b. Endangered and threatened 

wildlife and plants; Designation of critical habitat for the Mariana fruit bat 

and Guam Micronesian kingfisher on Guam and Mariana crow on Guam 

and in the Commonwealth of the Northern Mariana Islands; final rule. 

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revised recovery plan for the Sihek or Guam Micronesian kingfisher 

(Halcyon cinnamomina cinnamomina). Federal Register 69:23210-23211. 

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management plan for Navy lands, Guam. U.S. Department of the Navy, 

Pacific Division, Naval Facilities Engineering Command, Pearl Harbor, 

Hawaii. 

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epizootiology and ecological significance of malaria in Hawaiian land 

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distribution of endangered animals and plants in northern Guam. 

Micronesica 28:31-49. 
101

Wiles, G. J., D.W. Buden, and D. J. Worthington. 1999. History of 

introduction, population status, and management of Philippine deer 

(Cervus mariannus) on Micronesian islands. Mammalia 63:193-215. 

Wiles, G.J., J. Bart, R. E. Beck, Jr., and C. F. Aguon. 2003. Impacts of the 

brown tree snake: patterns of decline and species persistence in Guam’s 

avifauna. Conservation Biology 17:1350-1360. 

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1989. Reproductive activity of force-paired cockatiels (Nymphicus 

hollandicus). Auk 106:86-93. 

B. Personal Communications and Other References 

Bahner, Beth. 2001, 2003, 2004, 2008. Philadelphia Zoo, Philadelphia, 

Pennsylvania. Personal communication. 

Beck, Robert E., Jr. 1985. Guam Division of Aquatic and Wildlife Resources, 

Mangilao, Guam. Unpublished data. 

Brooke, Anne P. 2007. U.S. Navy, Commander of Naval Forces in the Mariana 

Islands, Guam. Personal communication. 

Buermeyer, Karl. 2008. U.S. Fish and Wildlife Service, Pacific Islands Fish and 

Wildlife Office, Honolulu, Hawaii. Personal communication. 

Burgett, Jeff. 2007. U.S. Fish and Wildlife Service, Pacific Islands Fish and 

Wildlife Office, Honolulu, Hawaii. Personal communication. 

Campbell, Earl W. 2004. U.S. Fish and Wildlife Service, Pacific Islands Fish 

and Wildlife Office, Honolulu, Hawaii. Personal communication. 

Dicke, Blaine. 2005. Guam Division of Aquatic and Wildlife Resources, 

Mangilao, Guam. Personal communication. 
102

Haig, Susan. 2002. U.S. Geological Survey, Oregon State University, Corvallis, 

Oregon. Personal communication. 

Junge, Randy. 2002. Saint Louis Zoo, Saint Louis, Missouri. Personal 

communication. 

Kesler, Dylan. 2002, 2003, 2004. Oregon State University, Corvallis, Oregon. 

Personal communication. 

Kessler, Curt. 2007. U.S. Fish and Wildlife Service, Pacific Islands Fish and 

Wildlife Office, Honolulu, Hawaii. Personal communication. 

Knutson, Kelly, and Scott Vogt. 2003. U.S. Air Force, Anderson Air Force Base, 

Guam and U.S. Navy, Pearl Harbor, Hawaii. Unpublished manuscript. 

Marshall, Joe T., Jr., and Robert E. Beck, Jr. 1985. New York Zoological 

Society, Bronx, New York and Guam Division of Aquatic and Wildlife 

Resources, Mangilao, Guam. Unpublished data. 

Medina, Suzanne. 2005. Guam Division of Aquatic and Wildlife Resources, 

Mangilao, Guam. Personal communication. 

Qualls, Fiona, and Carl Qualls. 2001. U.S. Geological Survey, Colorado State 

University, Fort Collins, Colorado. Personal communication. 

Vice, Dan. 2008. USDA Wildlife Services. Personal communication. 
103

VI. APPENDICES 

APPENDIX A 

Endangered and Threatened Species Recovery Priority Guidelines 

(adapted from USFWS 1983a,b). 

Degree of 

Threat 

Recovery 

Potential 

Taxonomy Priority Conflict 

1C Monotypic genus 1 1 

2C Species 2 2 

3C 

High 

Subspecies 3 3 

4C Monotypic genus 4 4 

5C Species 5 5 

6C 

High 

Low 

Subspecies 6 6 

7C Monotypic genus 7 7 

8C Species 8 8 

9C 

High 

Subspecies 9 9 

10C Monotypic genus 10 10 

11C Species 11 11 

12C 

Moderate 

Low 

Subspecies 12 12 

13C Monotypic genus 13 13 

14C Species 14 14 

15C 

High 

Subspecies 15 15 

16C Monotypic genus 16 16 

17C Species 17 17 

18C 

Low 

Low 

Subspecies 18 18 
104

APPENDIX B 

Glossary of Technical Terms 

allele Alternative forms of a gene that code for the same trait. 

Alleles usually occur in pairs, one at the same genetic locus 

on each of a pair of chromosomes. For example, in humans 

there are multiple alleles for blood type: O, A and B. If 

both of the alleles on each chromosome carry the same 

allele (e.g., AA), the individual is said to be homozygous at 

that locus. If the alleles are different (e.g., AB), the 

individual is heterozygous. 

arboreal Living or placed in trees; adapted for life in trees. 

avifauna The bird life or bird community of an area. 

coverts The small feathers on top of the wings (wing coverts), over 

the tail feathers (upper tail coverts), or under the tail 

(undertail coverts, or crissum). 

effective The functional size of a population, from a genetic 

population perspective, based on the number of breeding individuals 

size (often abbreviated Ne). The effective population size is 

generally smaller than the census population size (i.e., there 

may be numerous individuals in the total population that 

are not contributing genes to future generations, such as 

juveniles or senescent adults). 

extant Still existing, not extinct. 

heterozygosity A measure of the degree of genetic diversity in a 

population, as measured by the proportion of heterozygous 

loci across individuals (see allele, above). 
105

inbreeding The probability that two alleles at a genetic locus are 

coefficient (F) identical by descent from a common ancestor to both 

parents. The mean inbreeding coefficient of a population 

will be the proportional decrease in the observed 

heterozygosity relative to the expected heterozygosity of a 

founder population. 

interspecific Between different species; between individuals or 

populations of different species. 

intraspecific Within a species; between individuals or populations of the 

same species. 

mitochondrial The mitochondria are organelles responsible for energy 

DNA production within the cells. DNA is found in the 

mitochondria in addition to the DNA within the cell 

nucleus, but unlike nuclear DNA, mitochondrial DNA is 

inherited only through the mother. The high levels of 

variability in mitochondrial DNA and uniquely maternal 

inheritance are two of the characteristics that make analysis 

of mitochondrial DNA a common tool for investigating 

factors such as the degree of divergence between lineages. 

Ne see effective population size, above. 

snout-vent length A standard measurement of body length for reptiles. The 

 measurement is from the tip of the nose (snout) to the 

opening of the cloaca (vent), and excludes the tail.

ungulates Hoofed grazing mammals. Typically refers to animals in 

the orders Perissodactyla (odd-toed animals such as horses) 

and Artiodactyla (even-toed animals such as cows, sheep, 

goats, deer, and pigs). 
106

APPENDIX C 

Summary of the Agency and Public Comment on the Draft Revised 

Recovery Plan for the Sihek or Guam Micronesian Kingfisher 

(Halcyon cinnamomina cinnamomina)

 In April 2004, the U.S. Fish and Wildlife Service (Service) released the 

Draft Revised Recovery Plan for the Sihek or Guam Micronesian Kingfisher 

(Halcyon cinnamomina cinnamomina) for review and comment by Federal 

agencies, the Government of Guam, and members of the public. The public 

comment period was announced in the Federal Register (U.S. Fish and Wildlife 

Service 2004c) on April 28, 2004 and closed on June 28, 2004. Over 50 copies of 

the draft plan were sent out for review during the comment period. In addition, 

the draft revised plan was distributed to scientific peer reviewers for comment 

prior to finalization and publication of this final revised plan. We received 

comments from four peer reviewers. 

 Sixteen letters/comments were received during the comment period. 

Comments were received from two Federal agencies, one Territory agency, four 

peer reviewers, and nine private organizations or individuals. Since the comment 

period closed, additional information and updates to the plan have also been 

received by the Service. All comments received have been considered and 

incorporated into the approved recovery plan, as appropriate. A summary of the 

all of the major comments received and the Service’s response follow. 

Summary of Comments and Service Responses 

Issue 1: Life History of the Sihek 

Comment: The recovery plan’s discussion of kingfisher habitat requirements are 

inconsistent and it is inappropriate to relate Pohnpei kingfisher habitat 

requirements with those of the Guam kingfisher because the climate, soil, and 

plant community on Pohnpei is very different from Guam. 
107

Response: We agree that the habitat requirements of the Pohnpei Micronesian 

kingfisher may differ from the habitat requirements of the sihek. However, we 

believe that including information on the habitat requirements of Pohnpei 

kingfisher provides information about the potential needs of the sihek and may 

help facilitate conservation planning for sihek. Therefore, we have kept all of the 

discussion regarding Pohnpei kingfisher habitat needs. However, we have added 

additional language to qualify that the Pohnpei kingfisher and sihek may have 

different habitat requirements. 

Comment: One commenter suggested that additional research on the life history 

of the sihek is not needed. 

Response: We disagree that enough is known about the life history to make it 

unnecessary to do additional research on its life history. We believe that very 

little is known about the life history of the sihek and that additional research 

would greatly aid efforts to recover the species. For example, the research being 

done on the Pohnpei Micronesian kingfisher is being used to improve the captive 

breeding program for the sihek. 

Issue 2: Brown Treesnake Control

Comment: One commenter suggested that brown treesnake control efforts be 

placed higher in the step-down outline to emphasize their importance. 

Response: The step-down outline does not rank the importance of specific 

recovery tasks. The step-down outline simply categorizes the recovery tasks and 

lists them to show how they relate to one another. The recovery tasks are ranked 

using a three-tiered priority ranking system in the Implementation Schedule. 

Currently, brown treesnake control is one of the highest priority tasks in the 

recovery plan. 

Comment: One commenter suggested we develop a plan for ridding the island of 

Guam of brown treesnakes. 

Response: In 1996, as an effort separate from, and in addition to, recovery 
108

planning for the sihek, a brown treesnake control plan was developed with the 

purpose of controlling snakes on Guam and preventing their spread to other 

islands. This plan was developed with input from the Departments of Interior, 

Defense, and Agriculture; Government of Guam; and other parties. Currently, it 

is being revised based on input from an advisory committee. 

Comment: One commenter suggests that the island of Guam be sprayed with a 

snake-specific spray to rid the island of brown treesnakes. 

Response: We are not aware of a registered spray that specifically controls 

brown treesnakes, nor are we aware of efforts to develop such a spray. 

Comment: One commenter suggested that aerial drops of acetaminophen be 

conducted several years before reintroduction of the sihek because sihek may 

consume broadcast baits. 

Response: We agree that sihek consumption of aerial drop baits with 

acetaminophen is a concern and have added language to Recovery Task # 4.1.1, p. 

61, to that effect. 

Comment: One commenter suggested that the majority of funding be used for 

operational control and to maximize effectiveness of existing brown treesnake 

control techniques. Developing additional snake control techniques should be 

conducted last. 

Response: We agree that on-the-ground brown treesnake control (Recovery 

Task # 4.1.1) and improving existing snake control techniques (Recovery Task # 

4.1.4.2) are a higher priority than developing additional techniques (Recovery 

Task # 4.1.5). We have prioritized them accordingly in the Implementation 

Schedule. 

Comment: One commenter stated that including the estimated cost of predator 

control efforts is inappropriate until effective control techniques have been 

developed and implemented. 
109

Response: Under the Endangered Species Act, we are required to include 

estimated costs of recovery actions needed to recover the sihek. Based on 

currently available information, we estimated the cost to control brown treesnakes 

for recovery of the sihek using existing technology. These are only estimated 

costs and may change as new technology is developed and existing techniques are 

improved. 

Comment: One commenter state that the plan concludes that predators other than 

the brown treesnake are not expected to be a major threat to recovery yet the plan 

states that $900,000 is needed to address this issue. This is not consistent. 

Response: The recovery plan includes monitoring the potential impacts of rats 

and other predators on sihek as recovery tasks. We believe that these tasks are 

necessary because no predators studies were ever done on sihek prior to its 

extinction in the wild. The available information does not indicate that they will 

necessarily impact sihek recovery, however, when sihek are reintroduced to Guam 

and their populations are small, it may be possible that these predators may 

threaten the success of the program. This is especially true if rat populations 

increase after brown treesnakes are controlled. 

Issue 3: Captive Management 

Comment: One commenter stated that the Guam Micronesian Kingfisher is one 

of the most thoroughly managed captive populations and it seems unlikely that 

any additional resources can be applied to the list of actions outlined in the plan. 

Response: The recovery plan is intended to list the management actions that may 

be necessary to recover the species. As resources are limited, we believe that the 

allocation of these resources will need to be determined to best fulfill the needs of 

the species. In the Implementation Schedule, we prioritized each recovery task 

using a three-tiered system to help focus resources to the higher priority tasks. 

For those tasks with similar priority rankings, the parties involved in 

implementing these tasks will need to determine how best allocate funds. 

Comment: One commenter suggested that the irregular breeding of sihek 
110

appears to be due to density-related stress. They suggested that most of the 

sihek be moved to Guam or to other cages to reduce density of sihek under 

current conditions. 

Response: Sihek are housed in separate cages, except during breeding. In 

addition all breeding pairs are housed in separate cages away from other sihek. 

Therefore, we have no reason to believe that poor reproductive success is due to 

density-related stress. We do, however, agree that moving additional sihek to 

Guam would be beneficial, if captive propagation efforts there are found to be 

successful. 

Issue 4: Reintroduction 

Comment: One commenter stated that sihek should only be reintroduced when 

captive breeding facilities can ensure both a sustainable captive population and 

excess birds for release.

Response: We agree that releasing sihek into the wild before a viable long-term 

captive population is established is not an appropriate course of action at this 

time. However, if efforts to increase the captive population are not successful it 

may be necessary to evaluate other courses of action to help recover the species. 

At that time, we will seek the input of experts outside the Service on an 

appropriate course of action. However, because we have no reason to believe that 

a long-term viable population of sihek cannot be established, alternative courses 

of action are not included in the recovery plan. 

Comment: One commenter asked how large the captive population needs to be 

before reintroductions can occur. 

Response: This will need to be determined by the Guam Micronesian Kingfisher 

SSP which manages the captive population (see Recovery Task # 2.1). The 

number needed will be based on founder representation, the effective size of the 

population, and the annual population growth rate. 

Comment: One commenter stated that the plan contains no discussion on how 
111

sihek will be introduced to Guam. 

Response: Recovery tasks 3.1-3.6 describe the reintroduction planning process 

that will occur prior to a reintroduction of sihek. Because the planning process is 

not complete, a detailed discussion of how sihek will be introduced is not 

available at this time. The reintroduction plan (see Recovery Task # 3.7) will 

provide details on how sihek should be reintroduced into the wild when it is 

completed. 

Comment: One commenter suggested that the plan overlooks whether there is 

adequate food for sihek on Guam and asked if there have been any efforts to 

ascertain whether adequate food is available and are there any plans to re-stock 

Guam’s lizard populations. 

Response: Currently, there have been no formal efforts to evaluate whether there 

is adequate food for sihek on Guam and there are no plans to re-stock lizard 

populations. The availability of food will be evaluated prior to the reintroduction 

as part of the reintroduction planning process (see Recovery Task # 3.2.4) and the 

appropriate management measures will be implemented. 

Comment: One commenter asked whether we believe that snake numbers are 

low enough to start reintroducing sihek to Guam. 

Response: We do not believe that brown treesnakes are controlled at sufficient 

levels to allow for reintroduction. The captive population is also not large enough 

for a release on Guam. Both of these goals will need to be attained prior to a 

reintroduction on Guam. 

Comment: One commenter asked whether we were considering introducing 

sihek to Rota. 

Response: The recovery plan includes a task to evaluate other islands in the 

Mariana archipelago as potential release sites. While Rota’s potential as a release 

site could be evaluated under this task, we have no specific plans to introduce 

sihek to Rota at this time. 
112

Comment: One commenter suggested that sihek be released in other areas than 

Guam because the current level of brown treesnake control is not adequate and it 

does not appear that adequate control will even be possible. In addition, they 

suggested a healthy wild population on another island would be preferred over a 

stagnant captive population or a doomed release on Guam. 

Response: We have added additional discussion of this option in the recovery 

plan. Because we have no evidence at this time that sihek were ever found on any 

of the other islands in the Mariana archipelago, we believe Guam is ultimately the 

most appropriate location for reestablishing a wild population of sihek if brown 

treesnakes can be adequately controlled. We also believe it is premature to 

conclude that adequate snake control on Guam will not be possible. However, 

pending availability of suitable snake-free habitat on Guam, releasing genetically 

well-represented sihek on another island in the Mariana archipelago could be 

considered as a backup for the captive population and as a method for introducing 

captive-reared sihek to free-living conditions in a relatively safe context. Any 

potential sites for such an introduction would be carefully evaluated for their 

relative risks and benefits in comparison with retaining individuals in captivity or 

releasing them on Guam. 

Comment: One commenter suggested that effective snake control techniques 

should be developed and implemented before considering the release of 

kingfishers into the wild. 

Response: We agree that brown treesnakes should be effectively controlled prior 

to reestablishing sihek to Guam. Snake control at reintroduction sites (Recovery 

Task # 4.1.1) and improving existing control techniques (Recovery Task # 

4.1.4.2) are both high priority recovery tasks. The Recovery Strategy (p. 38) also 

states that effective brown treesnake control is needed prior to reintroduction of 

sihek. 
113

Issue 5: Habitat Protection and Management 

Comment: One commenter asked why the plan suggests that Government of 

Guam conservation lands be given to the Service for management. 

Response: The recovery plan does not suggest that the Government of Guam 

conservation lands be given to the Service for management. The recovery plan 

does suggest that additional management be conducted on these lands (see 

Recovery task # 4.8.2) but does not suggest this management be conducted by the 

Service or that the Service should control these lands. 

Comment: One commenter suggested that there probably is not enough suitable 

habitat on Guam to reach the recovery goals outlined in the plan. 

Response: Little is known about the habitat requirements of sihek on Guam (see 

Habitat Requirements, p. 12, for additional information). However, based on 

available information we believe that there may be adequate habitat available on 

Guam to reach the recovery goals of this species. However, we also believe that 

management of this habitat may be needed to improve its quality (Recovery Task 

# 4.9). 

Comment: One commenter suggested that introduced deer and pigs are not a 

threat to the recovery of the sihek because the forests on Guam have not changed 

over the last couple of decades and an ungulate eradication and habitat 

improvement program is not necessary. In contrast, another commenter suggested 

that browsing by high numbers of introduced ungulates has severely degraded 

native forests on Guam and habitat loss and degradation is a major concern for 

recovery of the sihek on Guam. 

Response: We agree that feral ungulates have been negatively impacting the 

native forests on Guam and that this will impact the recovery of the sihek. 

However, we believe that extent of this impact needs to be further evaluated to 

determine how best to manage for the recovery of the sihek. Although some 

research has been completed, we believe that the quality of existing sihek habitat 

should be assessed (Recovery Task # 4.9.1) and that the management of this 
114

habitat would benefit from a management plan (Recovery Task # 4.9.2). 

Issue 6: Competition and Harassment by Black Drongos

Comment: Several commenters suggested that black drongos are not a threat to 

the sihek and that evaluating their impact on sihek is not necessary. 

Response: We agree that the available information does not indicate that black 

drongos are a major threat to the recovery of the sihek. However, Maben (1982) 

did report harassment of sihek by black drongos in her study. This harassment 

could be problematic when sihek are first reintroduced to Guam and the sihek 

population is still small. Therefore, we believe it is necessary to monitor black 

drongo impacts on sihek and determine if drongo control efforts are needed 

(Recovery Task # 4.5). 

Issue 7: Southern Guam Population of Sihek 

Comment: One commenter suggested that the establishment of a sihek 

population in southern Guam is probably not possible and would be a waste of 

time and money under current circumstances. 

Response: We agree that establishing a sihek population in southern Guam is 

probably not an appropriate initial course of action, as much of the effort to 

control predators has been implemented in northern Guam. However, we believe 

that reestablishing a second population of sihek on Guam is vital to the recovery 

of the species. Southern Guam is an appropriate location for establishing this 

second population and as efforts to recover the species continue, it will be 

appropriate to begin efforts to establish sihek there. 

Issue 8: Public Outreach 

Comment: One commenter suggested that many of the outreach tasks are a 

waste of money and that the Guam public understands the brown treesnake and 

recovery situation. 
115

Response: We agree that much of the public on Guam is aware of the brown 

treesnake and recovery situation. However, this level of awareness was in large 

part due to previous public outreach efforts by local and Federal agencies. In 

order to maintain and increase this level of awareness, we believe additional 

outreach is needed as recovery efforts continue and progress. Public support and 

interest is vital to the success of the recovery program. 

Issue 9: Funding 

Comment: One commenter stated that the plan requires a sizable amount of 

funding to be implemented and it is unlikely these funds will be available. 

Without these funds the kingfisher will likely be functionally extinct. The 

commenter then suggested that the Service consider alternate uses of funding, 

such as reducing the spread of brown treesnakes to additional islands, that will 

benefit multiple species in the region. 

Response: We agree that implementing the plan will require a sizable amount of 

funding and that other species in the region could benefit if the available funding 

for sihek recovery was used elsewhere. However, we are required under the 

Endangered Species Act to conserve all threatened and endangered species 

despite their status and their likelihood of recovery. Therefore, we cannot give up 

our efforts to recover the species. We can, however, place a higher priority on 

recovery tasks that benefit sihek and other listed species in the Mariana Islands. 

The final recovery plan does include a large number of high priority recovery 

tasks, like brown treesnake control, that would benefit other listed species on 

Guam and in the Mariana Islands. 

Comment: One commenter stated that the plan is needlessly expensive and many 

of the tasks can be paid for by other federal entities like the Air Force and Navy. 

Response: We agree that implementing all of the recovery tasks contained within 

the recovery plan will be expensive. However, section 4(f)(1)(B) of the Act 

requires the recovery plan to include a description of such site-specific 

management actions as may be necessary to achieve the plan’s goal for the 

conservation and survival of the species; and estimates of time and the cost to 
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carry out those measures needed to achieve intermediate steps toward this goal. 

We have strived to include a description of all the management actions that may 

be necessary to recover the sihek based on the best available information and we 

have prioritized these tasks (see Implementation Schedule) to focus funding on 

higher priority tasks. As recovery tasks are completed and the species begins to 

recover, some of the lower priority tasks may become unnecessary. 

Comment: One commenter asked what happens when such a large estimated 

cost for recovery of a species is presented. Does it affect whether any progress is 

made on recovery efforts for that species? 

Response: Obtaining the total funding required to implement the recovery plan 

may be difficult and some of the more expensive tasks may take additional time to 

implement if all of the funding is not available. For the sihek, the most expensive 

recovery task is brown treesnake control. Unfortunately, with current technology, 

control of large areas is very labor-intensive and costly. However, brown 

treesnake control is also a high priority recovery task for the endangered Mariana 

crow, Guam rail, and Mariana fruit bat. Therefore, the costs estimates provided in 

this plan also cover tasks that would benefit other listed species. Because this 

recovery task benefits multiple species, it receives a higher priority for funding 

and in fact has already received a significant amount of funding. 

Issue 10: General Recovery Plan Format and Content Issues 

Comment: One commenter asked why the Service is writing a new recovery 

plan when nothing has changed since the 1990 recovery plan. 

Response: Prior to revising the recovery plan, we evaluated the 1990 plan to 

determine if it was still appropriate for the conservation needs of the sihek. We 

determined that the primary focus of the 1990 plan, brown treesnake control and 

sihek captive propagation, had not changed but the recovery efforts needed for the 

species, especially captive propagation, had become more focused. We also 

found that many of the recovery tasks outlined in the 1990 recovery plan for the 

sihek were completed (see Conservation Efforts, p. 25, for a description of tasks 

completed). Based on this evaluation we determined that the recovery effort for 
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the sihek would benefit from a revised recovery plan that was dedicated to this 

species. 

Comment: One commenter asked what was meant by the statement “Only 

federal agencies are mandated to take part in the effort,” in the implementation 

section. 

Response: Section 7(1)(a) of the Act states that all Federal agencies shall utilize 

their authorities in furtherance of the purposes of the Act by carrying out 

programs for the conservation of threatened and endangered species. State and 

local agencies are not required, under the Act, to carry out these programs. 

Comment: One commenter suggested that the implementation schedule includes 

numerous activities (e.g., research on rat predation, registering rodenticides, black 

drongo control, management of the Guam National Wildlife Refuge and Guam’s 

conservation areas, instituting core curriculum, etc.) that are not specific to the 

recovery effort and are inappropriate for a recovery plan. These activities distract 

from the plan and appear to be a massive research, public relations, and 

employment effort rather than a rigorous scientific-based and plausible recovery 

effort for the sihek. 

Response: We are required to provide a description of all management actions in 

the recovery plan that may be necessary to recover the sihek. Recovery of the 

species will require a wide range of actions from multiple parties. We have 

strived to be as comprehensive as possible in including recovery tasks that we 

believe are necessary to recover the species. We reevaluated the recovery tasks 

and removed several that were in the draft revised plan because we believe they 

may not be necessary for recovery. However, the majority of the recovery tasks 

included in the draft revised plan were also included in the final revised plan.