MANAGEMENT PLAN 

 OF THE 

PACIFIC AND CENTRAL FLYWAYS 

 FOR THE 

ROCKY MOUNTAIN POPULATION OF 

GREATER SANDHILL CRANES

Prepared for the: 

Pacific Flyway Council 

Central Flyway Council 

Secretaria de Medio Ambiente Recursos Naturales y Pesca 

U.S. Fish and Wildlife Service 

 

March 2007 
This management plan is one of a series of cooperatively developed plans for managing various species of 

migratory birds of the Pacific and Central Flyways. Inquiries about this plan may be directed to member 

states of the Pacific and Central Flyway Councils or to the Pacific Flyway Representative, U.S. Fish and 

Wildlife Service/MBMO, 911 N.E. 11th Avenue, Portland, OR 97232-4181, or to the Central Flyway 

Representative, U.S. Fish and Wildlife Service/MBMO, 755 Parfet Street, Suite 496B, Lakewood, 

Colorado 80215. 

Suggested Citation: Subcommittee on Rocky Mountain Greater Sandhill Cranes. 2007. Management 

plan of the Pacific and Central Flyways for the Rocky Mountain population of greater sandhill cranes. 

[Joint] Subcommittees, Rocky Mountain Population Greater Sandhill Cranes, Pacific Flyway Study 

Committee, Central Flyway Webless Migratory Game Bird Tech. Committee [c/o USFWS, MBMO], 

Portland, OR. 97pp. 

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TABLE OF CONTENTS

Page

 I. INTRODUCTION ..................................................................................................................... 1 

 II. NATURAL HISTORY.............................................................................................................. 2 

Physical Characteristics ......................................................................................................... 2 

 Food Habits ............................................................................................................................ 3 

 Reproduction ........................................................................................................................... 4 

 Population Dynamics .............................................................................................................. 6 

 Habitat Requirements.............................................................................................................. 8 

 

Breeding ......................................................................................................................... 8 

Migration........................................................................................................................ 8 

Winter............................................................................................................................. 9 

III. OBJECTIVES ............................................................................................................................ 12 

IV. STATUS..................................................................................................................................... 15 

 Distribution ................................................................................................................................ 15 

 Summer Range ....................................................................................................................... 15 

 Fall Pre-migration Staging Areas............................................................................................. 16 

 Migration Staging and Stopover Areas................................................................................... 16 

 Wintering Areas ...................................................................................................................... 24 

 Number and Population Counts ................................................................................................ 27 

 Habitat ........................................................................................................................................ 29 

 Breeding Areas........................................................................................................................ 29 

 Fall Pre-migration Staging Areas............................................................................................ 30 

 Migration Stopover Areas....................................................................................................... 30 

 Wintering Areas ...................................................................................................................... 30 

 Management and Research (Current Programs)........................................................................ 31 

 V. PROBLEMS............................................................................................................................... 42 
v 

VI. RECOMMENDED MANAGEMENT PROCEDURES.......................................................... 47 

 Habitat ........................................................................................................................................ 47 

 Habitat Conservation.............................................................................................................. 47 

 Inventory of Habitat ............................................................................................................... 54 

 Uses of Cranes............................................................................................................................ 54 

 Interpretive Programs............................................................................................................. 54 

 Hunting (harvest allocation and guidelines).......................................................................... 55 

 Crop Damage Control ..................................................................................................................... 62 

 Hunting Seasons..................................................................................................................... 62 

 Supplemental Feed Crop and Direct Feeding Programs ....................................................... 62 

 Hazing and Harassment ......................................................................................................... 63 

 Habitat Manipulation ............................................................................................................. 63 

 Extension Services ................................................................................................................. 63 

 Lethal Control ........................................................................................................................ 63 

 Population Surveys .................................................................................................................... 64 

 

 Annual Recruitment Survey................................................................................................... 64 

 Fall Population Survey........................................................................................................... 64 

 Funding................................................................................................................................... 65 

 Research .................................................................................................................................... 67 

 Refinement of Adult and Juvenile Survival Estimates ......................................................... 67 

 Spring Food Supplies and Wetland Availability in the SLV .......................................... ..... 67 

 Techniques for Controlling Crop Damage ........................................................................... 68 

 

VII. ANNUAL REVIEW OF PLAN AND REPORTING .............................................................. 68 

VIII. REFERENCES CITED.............................................................................................................. 69 

 IX. ACRONYMS USED ................................................................................................................. 76 

 
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Appendix A -- RMP Sandhill Crane Harvest Summary, 1981-2005 ...................................................... 77 

Appendix B -- Summary of Experimental Spring Surveys from 1984 -96 in SLV, CO......................... 80 

Appendix C -- Whooping Crane Introduction Experiment Summary.................................................... .. 81 

Appendix D -- Rationale for Modifying the Harvest Allocation Formula ........................................ ......... 82 

Appendix E – Summary of July 2006 Revisions ............................................................................... 84 

LIST OF FIGURES AND TABLES

Figure 1 -- Distribution of RMP Greater Sandhill Cranes........................................................ ............... 11 

Figure 2 -- September Survey Locations for RMP Greater Sandhill Cranes........................................... 23 

Figure 3 -- Migration Chronology of RMP Greater Sandhill Cranes............................................... ....... 25 

Table 1 -- RMP Pre-migration Staging Areas and Associated September Estimates.............................. 18 

Table 2 -- Peak Winter Counts of all Subspecies in the Rio Grande Valley, NM................................... 26 

Table 3 -- Recruitment of RMP Greater Sandhill Cranes in the San Luis Valley, CO ........................... 29 

Table 4 -- Annual RMP Greater Sandhill Crane Base Allocation and harvest........................................ 61 
1 

I. INTRODUCTION

Five populations of greater sandhill cranes (Grus canadensis tabida) have been identified in North America. 

These include the Eastern, Rocky Mountain, Lower Colorado River Valley, and Central Valley populations 

(Braun et al. 1975, Lewis 1977), and more recently, the Gulf Coast subpopulation of Mid-continent sandhill 

cranes (Tacha et al. 1984). Recent research in Texas (Ballard et al. 1997) indicates the Gulf Coast 

subpopulation may contain up to 36,000 greaters. That would make the Gulf Coast subpopulation largest, 

followed by the Eastern, Rocky Mountain, Central Valley, and the Lower Colorado River Valley. The 

Rocky Mountain Population (RMP) numbered more than 20,000 in September 2005. Currently, hunting is 

allowed only on the Rocky Mountain and Gulf Coast populations. 

The numbers and distribution of RMP cranes, while reduced from historic levels, expanded markedly from 

400-600 birds in the mid-1940s (Walkinshaw 1949) to 10,000-15,000 birds by 1971 (Drewien and Bizeau 

1974). Its current breeding range extends from central and western Montana south through central and 

eastern Idaho, western and central Wyoming, northern and central Utah, and northwestern Colorado (Fig. 1). 

Recent records confirm breeding in extreme southwestern Alberta, which probably involve RMP pioneers 

following the Rocky Mountain Front northward from Montana (Semenchuk in Drewien et al. 2001). The 

major spring and fall migration staging area is the San Luis Valley (SLV), Colorado, where virtually the 

entire population spends 3-4 months annually (Drewien and Bizeau 1974, Kauffeld 1982). Several 

important overnight stopovers are used by RMP cranes during spring and fall migration including Harts 

Basin and the Grand Valley, Colorado, and the Green River near Jensen to Ouray National Wildlife Refuge 

in Utah (Drewien and Bizeau 1974, Peterson and Drewien 1997) and Cochiti and Jemez reservoirs, New 

Mexico (Stahlecker 1992). The principal wintering area is the Middle Rio Grande Valley (MRGV), New 

Mexico. Smaller numbers winter in northeastern and southwestern New Mexico, southeastern Arizona, and 

the northern highlands of Mexico (Drewien and Bizeau 1974, Perkins and Brown 1981, Drewien et al. 

1996). On winter areas, RMP cranes mix with the Mid-continent population (MCP), and cannot be managed 

separately from, Canadian (G. c. rowani) and the more abundant lesser (G. c. canadensis) sandhill cranes 
2 

(Lewis 1977, Drewien and Bizeau 1974, Drewien et al. 1996). Based on harvest data collected in Arizona 

and New Mexico, the proportion of Canadian cranes in the harvest has been about 6% and 8% respectively. 

Harvest in areas outside of the MRGV is mainly comprised of lesser sandhill cranes. 

Attempts were made to introduce whooping cranes in the Rocky Mountain region. The first attempts used 

RMP greater sandhill cranes as foster parents. (Appendix C). 

This plan is a revision of the July 1997 RMP crane plan. Its purpose is to establish guidelines for 

managing RMP sandhill cranes. The plan addresses habitats (breeding range, fall staging areas, migration 

routes, fall and spring stopover areas, and winter areas), status, uses, current management, problems 

associated with the population, and crane hunting guidelines. 

II. NATURAL HISTORY

Physical Characteristics

Sandhill cranes are among the oldest existing species of birds (2.5 million years) (Tacha et al. 1992, 

Tacha et al. 1994). Sandhill cranes have heavy bodies and long necks and legs (Walkinshaw 1949, Tacha 

et al. 1992). Height extends to 1.2 m, wingspan to 2 m (Tacha and Lewis 1979), and weight may reach 

6.85 kg (Schmitt and Hale 1997). The bill is elongate and strong. The feet have four toes with sharp 

hooked claws, while the hallux is small and elevated. Sexes are monochromatic gray and generally 

indistinguishable even with cloacal examination (Tacha and Lewis 1979). Juveniles have a feathered 

crown, brown nape feathers (Tacha and Vohs 1984) and buff-colored secondary wing coverts (Drewien et 

al. 1995). Adults have red, pappilos skin on the crown and gray nape feathers (Walkinshaw 1949, Tacha 

et al. 1992). The greater sandhill crane (greaters) is the largest subspecies. Female greaters weigh an 

average 4,928 g (10.9 lb) and males average 5,554 g (12.2 lb). Wing chord measurements for greaters 

average 514 mm for females and 538 mm for males. Posterior culmen measurements average 97.7 mm 

for females and 103.6 mm for males. The tarsus measurement averages 228 mm for females and 239 mm 

for males (Schmitt and Hale 1997). Morphological data collected in Wyoming female greaters averaged 
3 

4,845 g, wing chord 524 mm, tarsus 231 mm, and posterior culmen 99 mm. Greater males averaged 

5,430 g, wing chord 545 mm, tarsus 239 mm, and posterior culmen 105 mm (Lockman et al. 1987). 

Food Habits

Sandhill cranes are opportunistic foragers, which allows them to adapt to changes in food availability 

(Mullins and Bizeau 1978, Reinecke and Krapu 1986). The specific diet depends on food availability in 

different seasons and/or locations (Tacha et al. 1992). Sandhill cranes exploit foods by probing 

subsurfaces with bills and by gleaning seeds and other foods on the land surface or in shallow marshes 

(Walkinshaw 1949, Tacha et al. 1992). Cranes probe at a depth greater than 15 cm to obtain nut-grass 

tubers (Guthery 1975). 

Food items eaten by marsh-nesting cranes include roots, browsed vegetation, snails (Helisoma spp.), 

crayfish (Cambarus spp.), small mammals, birds, frogs (Hyla crucifer, Rana pipiens), snakes, toads (Bufo

spp.) and various insects (Walkinshaw 1973). Cranes will attempt to take any potential food item of the 

proper size, including waterfowl eggs, ducklings (Armbruster 1987), and lemmings (Reed 1988). Young 

cranes (colts) feed almost exclusively on animal food during the preflight period (Lewis 1977). 

During migrations, cultivated grains are major food items (Lewis 1977, Kauffeld 1982, Tacha et al. 

1994). Cranes often feed in grain fields in the spring before nest sites thaw and again in late summer after 

the young fledge (Armbruster 1987). Important grains include barley in Idaho and Wyoming (Drewien 

1973, Lockman et al. 1987) and wheat in Colorado (Bieniasz 1979). Cultivated grains provide the 

necessary fat stores required during migrations and are accessible with minimum energy expenditures 

(Tacha et al. 1987). At staging areas macroinvertebrates (e.g., earthworms, snails, beetles) provide 

essential proteins and calcium not obtained from other sources and are the foods in shortest supply 

(Reinecke and Krapu 1986). 
4 

During winter, waste corn is the primary food of cranes in the MRGV and southwestern New Mexico. 

Other important foods eaten by cranes include chufa tubers, sorghum, alfalfa, grasshoppers, and isopods 

(Walker and Schemnitz 1987). 

Reproduction

Sandhill cranes are perennially monogamous with pair bonds maintained outside the breeding season 

(Walkinshaw 1949, Tacha et al. 1992, Tacha et al. 1994). Greaters have successfully nested in their third 

year (Lewis 1977). However, the most productive RMP greaters were > 7-8 years old (Drewien et al. 

2001). Pair bonds may form and dissolve before successful reproduction occurs (Nesbitt and Wenner 

1987). Following successful reproduction, mate changes are rare unless a mate dies (Tacha 1988, Nesbitt 

1989). RMP cranes arrive at Grays Lake, Idaho during late March or early April when the valley is still 

snow covered. In mid-April as weather moderates and snow levels decline, pairs disperse to breeding 

territories (Drewien 1973). 

After arrival, most breeding pairs establish territories 2-4 weeks before nest building and egg laying starts 

(Drewien 1973). Pairs become aggressive toward their young of the previous year and proclaim their 

territory with loud, synchronized unison calls (Walkinshaw 1973). Pairs return to the same territory 

annually and both members assist in territorial defense. Pairs maintain mutually exclusive territories, and 

maximum aggressive behavior occurs during the prenesting period as adjacent pairs reestablish 

boundaries and drive off trespassing non-territorial cranes (Drewien 1973). The male is the most active 

in territory defense and females are less likely to retain the territory after loss of mates (Nesbitt and Tacha 

1997). 

Most daily requirements are found within territories, including nest, feed, roost sites, escape cover, and 

water. These components can be supplied by large marsh complexes (Drewien 1973); smaller, scattered 

marshes (Walkinshaw 1973; Armbruster 1987); bogs in northern boreal forests (Taylor 1976); 

intermittent streams in sagebrush parklands (Bieniasz 1979); and mountain meadows, beaver (Castor 
5 

canadensis) ponds, and subirrigated wet meadows along riparian zones (Drewien and Bizeau 1974). 

Families use territories partially or entirely during prenesting, nesting, brood, and post-brood periods 

(Drewien 1973). RMP cranes at Grays Lake, Idaho, have the highest reported nesting density with a 

mean territory of 17 ha (Drewien 1973). Isolation from human activity appears to be an important 

criterion for selection and use of nesting territories by cranes. Sandhill cranes have the propensity to 

desert their nests or territories due to human disturbances (Walkinshaw 1973, Drewien 1973, Boise 1976). 

Nests may be established on dry-land sites with almost no nest material but are more often in water on 

piles of emergent aquatic plants, sticks, grass, mud, and sphagnum (Lewis 1977). Nest size and 

complexity vary by location; those on dry sites are small and contained little material while those in water 

were larger and usually contain considerable nest material (Drewien 1973). At Grays Lake, RMP greaters 

nest from late April through early July (Drewien 1973). 

Clutches contain usually two, occasionally one, or rarely three eggs (Lewis 1977). Average clutch size is 

1.9 but is smaller in more northern-breeding birds (Nesbitt 1989, Tacha et al. 1994). Incubation begins 

after the first egg is laid (Drewien 1973, Lewis 1977). Both sexes incubate; males and females share 

daylight incubation duties about equally, but the female is the primary nest attendant at night (Drewien 

1973, Nesbitt 1989). Nest success varies among years and locations. It averages about 50% but has been 

as high as 78% (Tacha et al. 1992, Tacha et al. 1994, Drewien 1973). After 28-31 days of incubation, 

eggs hatch asynchronously (Drewien 1973, Lewis 1977). Sandhill cranes raise a single brood per year 

but will renest following loss of eggs in northern nesting populations or loss of eggs or young in southern 

populations (Tacha et al. 1994). 

Hatching takes 24 to 36 hours. The precocial colt is dry in a few hours and is walking the next day. After 

the colt or colts hatch, the family moves to open uplands or meadows for feeding. The family returns to 

the marsh each night to roost, and it may return to the nest or the parents may build a platform for 

roosting (Lewis 1977). Both parents feed the young, but females do most post-hatch brooding (Tacha et 
6 

al. 1994). The colts’ diet during the preflight period appears to be almost exclusively animal food, but 

fledged young feed readily on agricultural grains in autumn (Lewis 1977). RMP greaters fledge at 67-75 

days (Drewien 1973). RMP greaters post-fledging brood size averages 1.31 (range 1.21-1.35) at Grays 

Lake, Idaho. Young are usually separated from the parental care at about 10 months of age (Drewien 

1973, Drewien et al. 2001, Tacha et al. 1994). 

Population Dynamics

 The sandhill crane is the most abundant of the world’s cranes (Meine and Archibald 1996). However, 

sandhill cranes have the lowest known recruitment (percent juvenile in fall) of any avian species hunted 

in North America (Drewien et al. 1995). For RMP greaters at Grays Lake, Idaho, nonbreeders comprise 

31-39 percent of the total population annually (Drewien 1973). 

Most sandhill cranes lay two eggs but usually raise only one young. Sibling aggression by the dominant 

colt increases when there is food stress. This enhances the survival of the dominant colt at the expense of 

its brood mate by dominating the food made available by the parents (Drewien 1973). The availability of 

food and water, weather and predation on the breeding grounds, not innate behavior, appear to primarily 

influence brood size (Drewien et al. 1995). 

Annual fall recruitment in RMP greaters is 7.9% (Drewien 2005). The mean brood size is 1.35. About 

20% of RMP recruitment comes from extra young in broods with 2 or rarely 3 young (Drewien et al. 

1995). 

Adult cranes are long lived, but mortality can be high for eggs and young. Crows (Corvus 

brachyrrhynchos) and striped skunks (Mephitis mephitis) are primarily egg predators while ravens 

(Corvus corax), raccoons (Procyon lotor), and coyotes (Canis latrans) prey on eggs and young 

(Armbruster 1987, Littlefield and Thompson 1987, Littlefield and Lindstedt 1992). Golden eagles 
7 

(Aquila chrysaetos) may be a significant mortality factor as attacks have been observed on sandhill cranes 

(Armbruster 1987, Drewien et al. 2001, Mitchusson 2003). 

Estimated annual survival rates for RMP cranes from 1972-1985 was 95% (Drewien et al. 1995). With 

expanded hunting throughout the RMP range, current annual RMP crane adult survival is estimated at 

89%. Most (>70%) mortality is due to human causes. Legal and illegal shooting accounts for 58.3% with 

hunting (53.9%) the single most important mortality factor. Other mortality factors are by unknown 

causes (24.4%), power line and fence collisions or entanglements (10.0%), and other factors (7.3%). 

The proportion of cranes lost to shooting increases with age, whereas non-shooting mortality declines 

with age, suggesting older cranes learn to avoid many forms of non-shooting mortality (Drewien et al. 

2001). 

Avian botulism (Clostridium botulinum) and avian cholera (Pasteurella spp.) are leading causes of nonhunting mortality (Windingstad 1988, Tacha et al. 1994). Avian tuberculosis (Mycobacterium avium), 

aspergillosis ( Aspergillus spp.) and lead poisoning are other causes of mortality (Tacha et al. 1992, Tacha 

et al. 1994). Hail storms and lightning are notable but localized environmental causes of crane mortality 

(Windingstad 1988). 

Since the 1980’s, incidences of avian cholera and avian tuberculosis in cranes have increased in the 

MRGV, and have been associated with increases in winter populations of lesser snow geese (Chen 

caerulescens) and Ross’s geese (Chen rossii) (Snyder et al. 1987, Taylor and Kirby 1990, Drewien et al. 

2001). Outbreaks of avian cholera in cranes at Bosque del Apache NWR (Bosque) have occurred in 9 

winters during 1984-1999 including a peak loss of 110 cranes in 1993-1994 (Drewien et al. 2001). 

Maximum known age of a wild RMP greater sandhill crane is 35.5 years (R. Drewien, per. comm.). 
8 

Habitat Requirements

The single most-important factor regulating sandhill crane populations is habitat availability (Tacha et al. 

1992). Thus, maintenance of essential habitats is the primary need for sandhill cranes (Tacha et al. 1994). 

Sandhill cranes are primarily birds of open freshwater wetlands and shallow marshes, but use a broad 

range of habitat types from bogs, sedge meadows, and fens to open grasslands and cultivated lands (Tacha 

et al. 1992). 

Breeding – RMP sandhill cranes nest in isolated, well-watered river valleys, marshes, and meadows at 

elevations mainly above 1,500 m in the northern and central Rocky Mountain states (Drewien 1973, 

Drewien and Bizeau 1974). Most nests are in wet meadow-shallow marsh zones along the marsh 

edge (Drewien and Bizeau 1974). After hatching, broods tend to feed in moist areas along the 

water’s edge or in adjacent meadows, using deeper water mainly for escape and occasional roosting 

(Drewien 1973). In Colorado, broods moved away from the willow drainage bottoms, upslope to the 

sagebrush ridges and the fringes of the aspen stands (Bieniasz 1978). Nonbreeding adults feed in 

wet meadows and grain fields adjacent to a roosting area. In August, cranes feed in alfalfa fields 

with large numbers of insects present. Use of grain fields increases during fall pre-migration staging 

where nearly all cranes observed are in grain fields (Rowland et al. 1992). Prior to migration, RMP 

greaters gather at staging areas near their summering site. The major attraction at staging areas is the 

availability of grain located in proximity to shallow lakes, marshes, and river bottoms that are used 

as roosting sites, and they feed primarily on barley near adjacent wetlands (Drewien and Bizeau 

1974). 

Migration- Habitats along migration routes tend to be large open palustrine and riparian wetlands 

near agricultural areas (Krapu et al. 1984). Wet meadows and native lowland grassland habitats are 

important as they provide an important source of macroinvertebrates for cranes (Reinecke and Krapu 

1986). At the spring and fall staging sites in the San Luis Valley (SLV), Colorado, roosting locations 
9 

are ponds and sloughs where the birds use water up to 0.3 m deep. Loafing areas are wet meadows 

of baltic rush (Juncus balticus), sedges (Carex spp.), spikerush (Eleocharis spp.), greasewood 

(Sarcobatus vermiculatus) and a variety of grass species. These meadows do not have to be very 

wet to attract cranes; 2 to 4 cm of water is satisfactory. Cranes will sometimes use dry meadows as 

long as a ditch with water or a stream is nearby. Although some feeding activity occurs in meadows, 

they are primarily used for resting, preening, and other social activities. The other major habitat 

used is grain fields during morning and evening. Barley is the primary crop so cranes use it most 

frequently, but will also utilize wheat, field peas, and potato fields. Primary feeding activity in 

potato fields is searching for insects and grubs (Kauffeld 1982). 

Winter - The quality of winter habitat is important because cranes congregate in high densities and 

are dependent on limited resources. Cranes are vulnerable to disturbance and habitat alteration 

caused by changes in water and cropland management (Iverson et al. 1985b). Cranes wintering in 

the MRGV roost in shallow river areas, lake areas, or artificial impoundments on state and federal 

refuges and spend most of the day in irrigated croplands and pastures. The riparian community is 

dominated by cottonwoods (Populus fremonii), Russian olive (Elaeagnus angustifolia), saltcedar 

(Tamarix chinensis), and willow (Salix spp.). State and federal refuges border the river and consist 

of riparian woodlands, cultivated fields, and artificial impoundments where water levels are 

manipulated for waterfowl and shorebirds. Impoundments having water throughout the year support 

plants such as hardstem bulrush (Scirpus acutus), spikerushes (Eleocharis spp.), rushes (Juncus 

spp.), and cattails (Typha spp.). Impoundments that are drawn down in spring produce above and 

below ground wetland food resources such as chufa (Cyperus esculentus), nodding smartweed 

(Polygonum lapathifolium), bearded sprangletop (Leptochloa facicularus), barnyard grass 

(Echinochloa crusgalli), yellow bristlegrass (Seteria glauca), cupgrass (Eriochloa spp.), Johnson 

grass (Sorghum halepense), and fall panicum (Panicum dichotomiflorum) (Taylor and Smith 2003). 

The remainder of the valley consists mostly of irrigated croplands. Cranes use the irrigated 

croplands for feeding and loafing. Common crops include alfalfa, chile, corn, cotton, and sorghum 
10 

(Walker and Schemnitz 1987). In the MRGV, the acreage of corn and small grains has decreased, 

causing cranes to concentrate on refuges and dairy farms where grains are raised. Wetlands are 

scarce because of drainage projects carried out by the Bureau of Reclamation (BoR) (Lewis 1977). 

Some of the RMP sandhill cranes migrate from the MRGV to areas in southwestern New Mexico, 

the Sulfur Springs Valley, AZ and the Northern highlands in Mexico (Drewien and Bizeau 1974). 

However, numbers wintering in southwestern NM are much reduced compared to the 1970’s due to 

the loss of sorghum crops (Drewien et al. 1996, Mitchusson 2003). 

Roosts sites used regularly by wintering birds generally are in shallow water several meters from 

shore. Physical features that characterize roosts are level terrain, shallow water bordered by a 

shoreline either lacking vegetation or only sparsely vegetated and an isolated location that reduces 

the chance of disturbance by humans. The ground slopes gradually into the water and a large area of 

10 to 20 cm deep water is present several meters from the shore, providing standing room for a 

flock. The shallow water between the cranes and the shoreline, level terrain and sparse vegetation 

permit a clear field of vision that provides some protection against predators. Optimal roost sites are 

located within 16 km (10 miles) of feeding areas (Lewis 1976). However, cranes fly approximately 

27 miles from Caballo Lake to cornfields in the Uvas Valley and return to roost on Caballo Lake (R. 

Drewien, per. comm., Mitchusson 2003). 

. 
11 

Figure 1. Distribution of the Rocky Mountain Population of Greater Sandhill Cranes (adapted from 

Drewien et al. 2001). 
12 

III. OBJECTIVES

The primary objective of this plan is to manage the RMP for numbers and distribution that will provide 

maximum direct benefits to the public and for the intrinsic values of the birds themselves. Objectives 

include: 

A. Manage for a stable population index of 17,000-21,000 cranes determined by an average of the 3 most 

recent, reliable September (fall pre-migration) surveys (see Table 1). 

 Interpretation

 A crane population of 19,000 (+ 10%) provides numerous opportunities to view birds, recreational 

hunting, and does not result in intolerable crop damage in most areas. There is currently sufficient 

habitat to support the population objective. An RMP in excess of 21,000 cranes may significantly 

increase the probability of crop damage, disease and overcrowding, particularly in the primary MRGV 

winter area. 

Most RMP cranes stage in specific locations throughout the summer range states during late August to 

early October, but migration chronology can vary between years. The September pre-migration survey 

is the best opportunity to survey the population. The objectives of this plan will be based on the 

September surveys. To minimize the potential effect of a poor count during a single year, population 

management decisions will be based on an average of the 3 most recent, reliable fall surveys. The 

survey team will provide insight into the reliability of the estimate based on survey timing, survey 

coverage and weather conditions. If a count is judged poor, it will be excluded from the average and 

the latest reliable 3-year average will be used for that year. All reliable surveys will be used towards 

the harvest allocation formula. However, if a prior survey is determined to be poor, such as if there 

was large decline in the population index followed the next year with a biologically unfeasible 
13 

population increase; the count estimated prior to the poor survey and current year survey will be 

averaged and used for the crane harvest allocation formula. 

B. Maintain and protect suitable habitats in sufficient quantity and quality to support population 

objectives and spatial distribution, while encouraging population expansion where desirable. 

 Interpretation

 Sufficient breeding, wintering, and migration habitat is required to maintain a stable population. Some 

areas of historic range suitable for nesting pairs are currently not occupied, and some staging and 

wintering areas are overcrowded. Breeding birds pioneering into unoccupied areas should be 

encouraged to expand, and migrating and wintering birds may be encouraged to use alternate areas 

through various management practices (e.g., creation of food plots, new roost sites, or protected areas). 

Cooperative management plan development between state management areas and federal refuges 

could significantly improve crane spatial distributions and habitat management across wide regions. 

Increasing human impacts on crane habitats will likely result in short and long-term habitat loss. As 

habitat is lost along with changing agricultural practices and crops, cranes are restricted to fewer 

areas. Food supply, roost sites and overcrowding are becoming priority concerns for population 

maintenance, especially on winter areas. 

C. Provide for recreational uses of RMP cranes. 

 Interpretation 

 Due to their large size and palatability sandhill cranes have long been hunted for food. Crane 

remains were found in ancient kitchen middens at Wupatki Pueblo, Arizona and in Rio Grande 

pueblos (Walkinshaw 1949). Crane hunting is the primary tool for reducing localized crop damage. 
14 

In most states demand exceeds the availability of permits (Lockman et al. 1987). Crane hunting 

alleviates many potential depredation complaints and garners support for crane management. 

 Interest in watching and photographing sandhill cranes is a popular activity. General wildlife 

watching and other nonconsumptive uses account for the majority of all wildlife associated 

recreation (U.S. Department of the Interior 1996). Crane festivals attract birders from across the 

country and other nations to view and photograph wildlife, and participate in other wildlife-related 

events contributing to the local economies (Mitchusson 2003). 

 

D. Minimize crop depredations by RMP cranes. 

 Interpretation

 Large numbers of sandhill cranes utilize private lands in the Rocky Mountain region. RMP cranes 

forage primarily in agricultural areas causing significant damage to agricultural crops. Some 

landowners tolerate crane use on private lands, while others have been quite vocal and have filed 

complaints with the U.S. Department of Agricultural-Animal Plant Health Inspection Service-Wildlife 

Services (Wildlife Services) and state agencies. Hunting seasons are the most effective means to 

reduce sandhill crane depredations, provide recreational opportunity and improve crane spatial 

distributions. Crane hunting along with hazing and timed crop manipulations on refuges can be used 

to encourage crane use on refuges and reduce agricultural damage (Taylor 1999). 

 While agricultural producers may be satisfied with the depredation control work, a growing number of 

landowners do not support the program. These are generally small landowners who do not derive the 

majority of their income from agricultural production and enjoy the sights and sounds of cranes on 

their property. Balancing depredation control work, particularly when such properties are adjacent to 

one another can be a delicate task for field personnel (Taylor 1999). Increasing urbanization will 

likely exacerbate this conflict. 
15 

IV. STATUS

Distribution

Summer Range 

Historically, RMP cranes nested in suitable habitats throughout the central and northern Rocky Mountains 

and the Great Basin from northeastern Arizona, central Utah and western Colorado north through western 

Wyoming, Idaho, western Montana, and probably Alberta. Reports from explorers and settlers indicate 

cranes were common to abundant throughout this area until late in the nineteenth century (Drewien and 

Bizeau 1974). By the early 1900s, cranes had become uncommon to rare or were extirpated within this 

region. The dramatic decline is attributed to a combination of factors but was principally due to habitat 

alteration, increased human intrusion on breeding areas, and subsistence harvest. The current summer 

distribution is shown in Figure 1. 

Numbers of RMP cranes increased from an estimated 150-200 breeding pairs in the mid-1940s (Walkinshaw 

1949:134) to an estimated spring population of 20,382 in 1985 (Benning et al. 1997). The 2005 fall premigration survey estimated a population of 20,865 (Drewien and Thorpe 2005). Much of their former 

nesting range has been reoccupied, except western Colorado, northeastern Arizona and Alberta. Recent 

records confirm breeding in extreme southwestern Alberta, which probably involve RMP pioneers 

following the Rocky Mountain Front northward from Montana (Semenchuk in Drewien et al. 2001). 

During the 1970s-80s, Grays Lake NWR in southeastern Idaho supported the largest nesting concentration 

(on a per acre basis) with about 250-300 pairs. The population recovery was attributed to protection from 

unregulated hunting, expansion of small grain agriculture, and establishment of refuges and management 

areas throughout most of the RMP Range. 
16 

Observations indicate RMP cranes are returning to the marshes of the Great Salt Lake Basin, river valleys in 

south-central Utah, and suitable habitats in eastern mountain valleys in Utah and western Colorado. Nesting 

pairs have pioneered east of the Continental Divide in Wyoming, Montana, and Colorado. 

We lack reliable estimates of breeding pair numbers over much of the summer range due to the difficulty of 

locating widely dispersed birds. Considering the estimated numbers of RMP cranes (about 20,000), their 

age structure, and recruitment rate, it is reasonable to expect at least 4,700 breeding pairs exist. 

Also, considerable breeding habitat for RMP cranes is located in the Rocky Mountain "Over-thrust Belt," a 

primary gas and oil extraction area where human intrusion has increased greatly in recent years and 

continues to increase at a rapid pace. 

Fall Pre-migration Staging Areas

Staging areas used in fall prior to migration have been identified in Idaho, Wyoming, Utah, Montana, and 

Colorado (Table 1, Fig. 2). Most staging areas are attractive to cranes because of the availability of grain 

crops and other forage. Damage to unharvested small grains is common and damage to unharvested seed 

potatoes is serious in some locations of eastern Idaho. Maintenance of staging areas will require specific 

plans for controlling and alleviating crop damage (see Problems and Recommended Management 

Procedures sections). Normally, crane numbers peak at specific staging areas in September but timing varies 

somewhat by area and year. Not all cranes migrate from their staging locations at the same time. Changing 

land uses and agricultural crops have altered staging areas resulting in some areas being less suitable as crane 

habitat (e.g., Star Valley and Bear River Valley, WY). 

Migration Staging and Stopover Areas

During spring and fall migration, many RMP cranes stop overnight or for several days at locations in 

western Colorado, northern New Mexico and northeastern Utah. Sightings of color-marked cranes indicate 

many consistently use 4 locations in addition to the SLV, Colorado; (1) the Green River Valley between 
17 

Jensen and Ouray NWR, Utah, (spring and fall), (2) Hart’s Basin near Eckert, Colorado (spring) (Peterson 

and Drewien 1997); 3) Grand Valley, Colorado (near Grand Junction); and 4) northern New Mexico 

(Stahlecker 1992). Smaller numbers of migrating cranes stop at other localities, notably sites in the 

Gunnison and White River Valleys, Colorado. 

The SLV is the only major migratory staging area for the RMP. In the SLV, RMP cranes mix with other 

crane subspecies from the MCP. Peak use occurs from late September to early November (ranging from late 

August to mid-December) and from late February to early April (ranging from late January to early May). 

Most cranes concentrate on the western side of the Valley, near the Monte Vista NWR, the Higel and Rio 

Grande State Wildlife Areas, and private lands adjacent to the Rio Grande between the towns of Alamosa 

and Monte Vista (Drewien and Bizeau 1974, Kauffeld 1982, Drewien et al. 1995, 2001). Other areas in the 

valley, primarily the eastern and southern portions of the SLV, including the Alamosa NWR, are used to a 

lesser degree. Crane roosting and foraging is increasing in northern portions of the Valley, which is 

probably due to the increase in the number of shallow water wetlands now available as roosts. Crane use is 

increasing at Russel Lakes State Wildlife Area (SWA). Private wetlands around the towns of Hooper and 

Mosca provide crane habitat. Also there is more crane use north of the Alamosa NWR on the newly 

acquired Baca National Wildlife Refuge and The Nature Conservancy wetlands on the Zapata-Medano 

Ranch. Crane-use days on the Monte Vista NWR between 1976 and 1981 ranged from 281,000-509,600 

and averaged 386,000 when the population was approximately 15,000 (Kauffeld 1982). Crane use days on 

the Alamosa NWR ranged from 8,900-53,100 and averaged 29,800. The majority of crane use on the 2 

refuges occurs in the spring. Small grains are not harvested in the fall but left standing until spring to feed 

migrating cranes and other migratory birds when waste grain is in short supply elsewhere in the valley. 
20 

Table 1. RMP Pre-migration Staging Areas and Associated September Estimates. Survey Area 1992 1995 1996 1997 1998 1999 2000 2001 2002 

Colorado

(1) Yampa Valley  (includes Hayden area and Morgan Bottom) 412 955 463 584 1,200 401 526 641 778 (2) Lower Elk River (combined with Yampa  V. from 1998-2002, possibly in 1996-97) 37 

(3) Delta Co. - Fruitgrower's Res.\Hart's Basin 0 

 Delta Co. – other (4) San Luis Valley 2,769 1,292 792 1,020 73 701 223 25 577 Subtotal 3,181 2,284 1,255 1,604 1,273 1,102 749 666 1,355 

Idaho

(1) American Falls Reservoir 0 14 8 NS 44 74 97 104 66 (2) Ashton-St. Anthony  (area combined in 1995) 898 1,076 1,659 1,844 987 1,516 1,405 1,485 1,876 1(3) Bear Lake Valley  (combined w/Bear River Valley in 2000) 594 116 476 403 416 439 

 Bear River Valley 568 617 668 760 734 1,267 815 790 1

(4) Blackfoot Reservoir 310 2,110 1,388 1,232 1,626 1,188 1,168 698 441 (5) Camas NWR 131 229 212 418 268 192 429 257 331 (6) Camas Prairie  (combined with Carey for 1995 survey) 0 0 0 2 93 25 17 137 0 (7) Carey Lake area  (combined with Silver Creek in '92,'96,'97  and Camas Prairie in '95 surveys. 264 156 87 0 8 0 6 2 

(8) Chesterfield Reservoir 0 196 249 273 218 355 149 170 86 (9) Grays Lake 343 636 606 747 1,156 1,144 1,529 1,734 1,467 1(10) Henrys Lake Flats 0 139 633 539 532 695 436 31 102 

(11) Island Park Reservoir NS 30 0 4 5 2 0 0 13 (12) Kilgore 2 121 0 17 2 0 0 0 0 NS (13) Market Lake WMA 13 NS 2 0 0 0 2 2 2 (14) Marsh Valley NS 182 45 172 244 324 284 192 277 (15) Mud Lake WMA 257 NS 50 50 130 62 105 94 172 (16) Oxford Slough-Swan Lake 0 330 47 316 52 418 94 143 242 (17) Silver Creek  (combined with Carey Lake Area in '92,  '96, '97 surveys, see Carey Lake Area for  estimates) 111 486 115 524 385 327 

(18) Teton Basin 2,989 1,006 2,186 1,360 1,048 1,470 1,831 907 1,504 1Subtotal 

5,801 6,864 8,334 8,132 8,067 8,761 9,337 7,160 7,698 7
21 

 Rich County  (see Bear River V. and Round Valley  after ‘92) 599 418 

(5) Morgan County 31 6 NS NS 18 NS 18 

Survey Area 1992 1995 1996 1997 1998 1999 2000 2001 2002 2003 

Montana

(1) Blackfoot/Ovando Valley  (includes Helmville) 343 422 385 167 561 246 258 272 453 514 (2) Cascade-Ulm 0 NS NS NS 94 NS 146 87 (3) Centennial Valley 35 20 3 NS 33 3 2 8 12 46 (4) Deadman's Basin  (may have been listed under  Mussellshell R. in '99) 80 329 284 164 400 655 48(5) Dillon-Twin Bridges 2,568 971 1,434 1,334 971 1,464 1,058 1,918 1,350 1,68(6) Gallatin Valley  (includes Belgrade) 200 229 258 213 232 35 327 273 340 41(7) Helena Valley 125 111 100 30 89 73 134 146 164 170 (8) Melville  (Otter Cr. and Melville reported  combined in '99) 257 224 NS 420 470 289 134 375 58(9) Musselshell River  (Includes Harlowtown)  (Melville/Otter Cr./Musselshell River  reported together in '97) 440 456 NS 1037 248 297 679 377 59 202 (10) Otter Creek  (Otter Cr. and Melville reported  together in '99, see Melville for estimate) 112 290 377 8 (11) Teton River - Eureka Res. (12) Toston-Townsend 234 229 106 158 183 NS NS NS 297 306 (13) Upper Madison Valley  (includes Ennis, Ennis estimate of  239 added to this estimate for 1992) 244 86 114 31 77 74 71 139 82 120 (14) Warm Springs 287 224 221 156 NS 139 261 116 137 7(15) White Sulphur Springs 309 709 353 405 229 NS NS 360 227 175 (16) Whitehall 142 NS NS 64 43 56 149 152 169 11Subtotal 5,264 3,681 2,974 3,595 3,415 3,141 3,598 4,585 4,843 4,964 

Utah

(1) Cache County 1,067 608 694 702 851 807 637 646 566 70(2) Box Elder County 222 255 225 457 402 576 288 338 362 425 (3) Davis County 16 46 39 148 121 117 44 133 82 87 (4) Weber County 46 57 47 49 96 23 37 15 39 148 
22 

survey A shaded cell indicates that the area was not listed in the report for that year, the name has been changed/discontinued, or the area has been drop

Survey Area 1992 1995 1996 1997 1998 1999 2000 2001 2002 2003  Utah(6) Bear River Valley 484 548 458 254 329 110 218 298 

(7) Round Valley 65 31 16 7 8 9 30 52 (8) Summit County 135 138 121 113 102 24 80 78 108 39  Uintah County  (see Jensen, Pelican Lake, Leland  Bench after ‘98) 632 NS 174 402 139 

(9) Jensen (Uintah Co) 459 933 114 446 747 

(10) Pelican Lake area (Uintah Co) 25 60 0 18 2(10) Leland Bench (Uintah Co) 61 0 10 

 Utah County 62 0 0 NS NS 

Subtotal 2,810 1,528 1,849 2,450 2,185 2,292 2,416 1,522 1,869 2,546 

Wyoming

(1) Baggs 60 NS NS 10 NS 0 0 2 3 4 (2) Bear River Valley 526 197 83 102 73 133 115 324 246 233 (3) Greybull River-Otto 208 0 363 161 411 524 585 207 286 439 (4) Shoshone River-Ralston (see Powell,  Park Co. in 1992) 429 365 476 258 466 1,023 802 268 414 742  Other Bighorn Basin 15 

(5) Big Piney 0 NS NS 0 55 399 0 135 40 174 

(6) Bridger Valley NS 27 42 140 8 57 0 3 33 125 

(7) Farson 388 323 806 895 1,192 889 1,367 890 1,051 813 

(8) Hams Fork 73 NS NS 0 NS 11 0 6 0 4 

(9) Pinedale-Cora 2 NS NS 5 6 17 29 12 2 2 

(10) Seedskadee NWR 0 NS 2 10 12 5 5 6 6 2 

(11) Saratoga 

 (Upper North Platte Valley) 43 NS NS 58 87 28 0 NS 0 193 (12) Jackson Hole 0 NS NS 36 48 41 69 72 121 117 

(13) Star Valley 

 (includes Lincoln Co, Salt River) 477 543 493 254 549 515 519 408 304 316 (14) Hidden Valley 

 (includes Boysen-Riverton area) 9 93 56 311 255 187 223 33 58 39 (15) Ocean Lake 8 123 205 234 176 240 433 229 

(16) Riverview Valley 142 0 20 41 14  Yellowstone Park 25 

 Subtotal 2,248 1,671 2,526 2,255 3,162 4,205 3,890 2,626 3,038 3,446 Totals 19,304 16,028 16,938 18,036 18,102 19,501 19,990 16,559 18,803 19,523 
23 

1 2

3

4

5

6

7

8

9

10

12

13

14 15

16

1

2

3

4

5

6 7

8 9

10

1211

13

14

15

16

17 18

2 1

3

4

5

6

7

8

9

1

2

3

4

5

6

7 8

9

10

11

12

13 14 15

16

1-2

4

Montana 

Idaho 

Wyoming 

Utah 

Colorado 

San Luis Valley

n = > 500 cranes 

n = < 500 cranes 

Fig. 2. September Survey Locations for the Rocky Mountain Population of Greater Sandhill Cranes. See 

Table 1 for location names and numbers (adapted from Drewien and Thorpe 2005). 

10

11

3
24 

Wintering Areas

From northern staging areas, most RMP cranes funnel through the SLV, Colorado, into the Middle Rio 

Grande Valley, New Mexico, southwestern New Mexico, southeastern Arizona, and northern Mexico 

(Fig. 1). Figure 3 shows the chronology of migration. Most RMP cranes terminate migration in Valencia 

and Socorro counties of the MRGV, New Mexico. Smaller numbers winter in southwestern New Mexico 

(Sierra, Grant, Dona Ana, and Luna counties) and the Pecos Valley in eastern New Mexico, including Las 

Vegas NWR, Maxwell NWR, and the Sulphur Springs Valley in Cochise County, Arizona. There appears to 

be an increasing trend of RMP cranes wintering on Las Vegas NWR and Maxwell NWR. About 10% 

continue into Chihuahua and Durango, Mexico, where they mix with the more abundant lesser and some 

Canadian sandhill cranes (Drewien et al. 1996). 

On all winter areas, RMP cranes mix with other subspecies. In the MRGV, Gila River Valley, Las Vegas 

NWR and Maxwell NWR, RMP cranes comprise the majority of winter flocks. The proportion of lesser and 

Canadian sandhill cranes wintering in the MRGV has been increasing in recent years. In other winter 

localities, especially southwestern New Mexico, southeastern Arizona, and Mexico, smaller subspecies 

predominate. In 2004, Arizona counted 31,443 cranes in the Sulfur Springs Valley. Of those, 20-30% are 

estimated to be RMP cranes. The total number of RMP cranes wintering in this area has increased markedly 

in this area within the last 20 years although the percentage of RMP has remained relatively constant. Some 

of this may be due to declining habitat conditions in Mexico and changing agricultural crops in southwestern 

New Mexico. Current estimates of the number of wintering cranes vary between years in the middle Rio 

Grande Valley, New Mexico (Table 2). 

Of the greater sandhill cranes that wintered in New Mexico and Arizona during the 1980s, 6,000-13,000 

wintered on Bosque NWR. Peak winter counts in the MRGV are summarized in Table 2. Use of state 

waterfowl management areas varied from 5,000-19,000 cranes. 
25 

In some years, from 2,000-12,000 cranes winter from Sierra County, New Mexico southwest to the Mexican 

border. In the late 1980s, an average of approximately 2,500 cranes wintered in this region. Areas of 

heaviest use include Caballo Lake, Uvas Valley and the Gila River Valley (Schmitt and Hale 1997). Crane 

use in Luna County has declined substantially due to agricultural changes in crops from grain to cotton and 

chile (Mitchusson 2003). In 1970, nearly 8,000 cranes wintered near Columbus, New Mexico (Drewien and 

Bizeau 1974), where few are found today. Numbers vary widely among years, but they are predominately 

lesser sandhill cranes (76.9%), followed by greater (18.7%) and Canadian (4.3%) sandhill cranes, except in 

the Gila Valley where greaters predominate. Moving southwest from the Rio Grande Valley to the Uvas 

Valley and to Guzman Basin near Deming and Columbus, the percentage of lessers increases from 63.2% to 

88.6%, while greaters decrease from 28.9% to 10.0% and Canadians decrease from 7.8% to 1.3% (Schmitt 

and Hale 1997). Recent crane harvest data from Arizona and southwest New Mexico indicate the percentage 

of Canadians has increased. 

0

10

20

30

40

50

60

70

80

90

100

Aug. 15

Sept. 1

Sept. 15

Oct. 1

Oct. 15

Nov. 1

Nov. 15

Dec. 1

Dec. 15

Jan. 1

Jan. 15

Feb. 1

Feb. 15

Mar. 1

Mar. 15

Apr. 1

Apr. 15

1-May

15-May

Percentage of Annual Peak Crane 

Numbers Present

Gray's Lake, ID Monte Vista NWR, CO

Bosque del Apache NWR, NM

Figure 3. Migration Chronology of RMP Greater Sandhill Cranes From Breeding Grounds to Migration 

Stopover and Winter Ranges and Return (adapted from Drewien and Bizeau 1974). 
26 

Table 2. Peak Winter Sandhill Crane Counts (all subspecies) in the Rio Grande Valley, New Mexico. Counts 

include 3 subspecies from the Rocky Mountain and Mid-Continent Populations.

___________________________________________________________________________________ 

 Bosque del Apache N D J1

Year National Wildlife Refuge Off-Refuge Count Total Mean 

1967 5,100 197 5,297 - 

1968 5,500 661 6,161 - 

1969 6,100 1,238 7,338 - 

1970 9,800 2,171 11,971 - 

1971 10,000 3,920 13,820 - 

1972 10,500 2,476 12,976 - 

1973 12,300 3,548 15,848 - 

1974 8,500 4,951 13,451 - 

1975 7,500 10,472 17,972 - 

1976 9,900 5,549 15,449 - 

1977 14,400 4,998 19,398 - 

1978 11,800 2,747 14,547 - 

1979 12,500 4,883 17,383 - 

1980 13,928 5,409 19,337 - 

1981 12,900 7,702 19,864 - 

1982 12,000 10,864 22,864 - 

1983 14,400 10,930 25,330 - 

1984 10,900 5,529 16,429 *15,056 

1985 11,000 6,029 17,029 *12,751 

1986 2

 4,629 18,430 23,059 *19,168 

1987 2

 8,334 20,282 29,126 19,421 

1988 2

 11,302 12,056 23,358 20,809 

1989 2

 6,196 10,357 16,553 15,383 

1990 2

 13,810 10,660 24,470 19,037 

1991 2,3 12,900 10,280 23,180 17,064 

1992 2,3 11,160 10,300 21,460 18,412 

1993 2,3 10,570 15,200 25,770 23,030 

1994 2,3 15,700 9,200 24,900 21,162 

1995 2,3 15,312 10,200 25,512 19,753 

1996 2,3 13,000 8,250 21,250 18,093 

1997 2,3 10,440 10,740 21,180 17,133 

1998 2,3 12,950 15,400 28,350 24,203 

1999 2,3 11,900 15,240 27,140 21,103 

2000 2,3 12,200 18,690 30,890 21,023 

2001 2,3 11,090 21,065 32,155 23,510 

2002 2,3 13,500 16,565 30,065 23,399 

2003 2,3 12,490 19,560 32,050 22,685 

2004 2,3 13,941 14,813 28,754 22,876 

2005 2,3 12,000 15,250 27,250 23,093 

___________________________________________________________________________________

1

 Average population during November, December, and January. 

2

 Beginning in 1986, Bosque del Apache NWR was included in the Rio Grande transect. Previously, data consisted of ground counts

by personnel of Bosque del Apache NWR. 

3

 1991-96 counts were based on weekly ground surveys during November-February.

* Denotes a year when data from ground count were used to determine the NDJ average. 
27 

Number and Population Counts

Historically, the SLV in March was the best location to census the RMP. Virtually the entire population is in 

the valley between 5-15 March. Beginning in March 1984, the U.S. Fish and Wildlife Service (FWS) 

annually counted cranes in the SLV using a systematic aerial transect survey with a photographic correction 

factor (Benning et al. 1997). Adverse weather conditions, including partial snow cover and high winds, 

occasionally reduced visibility, producing some counts of questionable accuracy. During 13 counts (1984-

96) the estimated number of RMP cranes averaged 17,725 and during 7 years of good survey conditions, 

averaged 19,869 (Appendix B). 

During early years of the March survey, a small number of Mid-Continent lesser sandhill cranes (<5%) 

mixed with the RMP. Ground surveys provided an index of the presence of lesser sandhills, and the RMP 

counts were adjusted accordingly. In recent years, lesser and Canadian sandhill cranes have increased to 22-

33% of the March crane population. Due to our inability to accurately distinguish the mid-sized Canadian 

subspecies through ocular surveys or track measurements, a reliable estimate of the RMP is no longer 

possible in the SLV in March. 

The Subcommittees concurred with the assessment by Drewien and Benning (1996, pers. comm.) that spring 

counts do not provide a reliable population estimate for the RMP. The spring survey was abandoned in 1997 

and has been replaced with a September pre-migration survey in the summer range states. The time period 

in September for a reliable survey is relatively brief and is weather-dependent, and is not confounded by the 

presence of other subspecies. Coordinated surveys must be done within a minimal time frame to avoid 

duplicate counting or missing birds that move. 

Carefully coordinated surveys of the RMP on fall pre-migration staging areas provide a minimum estimate 

of the population at that point in the biological year. Some hunting mortality has already occurred during 

early September seasons. Additional hunting mortality takes place during mid- and late September seasons, 
28 

and during later hunting seasons in winter range states. Limited overwinter mortality is also expected on 

wintering grounds and during spring return migration. 

Population estimates derived from fall pre-migration surveys in 1995-97 ranged from 16,000-18,000, but are 

considered minimal due to organizational problems and protocol associated with initiating a new survey. 

Recent satellite telemetry research confirmed no other known crane population co-mingles with RMP 

cranes during the September pre-migration survey (G. Krapu, per. comm.). Mid-continent cranes are present 

in the SLV during October. Therefore, fall surveys in the pre-migration areas form a solid basis to derive 

population indices for management decisions. 

In a 1969-71 study of RMP cranes nesting at Grays Lake, Idaho, Drewien (1973) found that certain 

information on production could, with caution, be extrapolated to the population elsewhere. Clutches 

averaged 1.9 eggs, and nest success was 78%. Cranes were capable of renesting when clutches were lost 

prior to mid-incubation. Mean brood sizes at hatching and fledging were 1.77 and 1.35, respectively. RMP 

greaters post-fledging brood size averages 1.31 (range 1.21-1.35) (Drewien et al. 1995). 

Recruitment rates at Grays Lake were high, 13-14% during 1961-71. However, population recruitment rates 

recorded in the SLV declined during the late 1980s-mid 1990s (Drewien et al. 1995). The 1982-85 average 

recruitment of young was 8.3% and the 1986-95 average was 5.2%. Drewien's studies indicate decreased 

production was caused by a drought in recent years, during which predation on young increased. An 

apparent increase of predation by coyotes coincided with changes in predator control practices including 

elimination of compound 1080 by the FWS beginning in 1972. 

Below normal recruitment from 1986-1995 had reduced the population from the 1985 level of 20,382. 

Habitat deterioration (long-term drought and poor wetland conditions) and predation are cited as the primary 

factors impacting recruitment (Drewien et al. 1995). Changes in farming practices in the SLV may also be 

impacting food availability to pre-nesting cranes during the spring migration. However, recruitment 
29 

rebounded to 9.4% in 1996, in response to improved wetland conditions on breeding areas. Recruitment 

from 2000-2005 averaged 8.0%. Recruitment from 1972-2005 averaged 7.9% (Table 3). Hunting in the 

northern states occurs prior to the SLV recruitment survey in addition to other mortality factors occurring 

during migration. This may influence observed recruitment, as juveniles have higher mortality rates 

(Drewien et al. 2001). 

Habitat

Breeding Areas

Typical nesting habitat occurs in the river valleys, marshes, and wet meadows of northern Colorado, 

northern and central Utah, western and central Wyoming, southeastern and central Idaho, and central and 

western Montana, particularly in ranching country where human populations are low, but increasing. 

Increases in home development and subdivisions are negatively impacting some habitats in portions of 

eastern ID, western WY, and southwestern MT (Drewien and Thorpe 2005). Suitable, vacant crane habitat 

may be available in western Alberta where the possibility for population expansion may exist. 

Table 3. Recruitment (% juv.)in Rocky Mountain Greater Sandhill Cranes, 

San Luis Valley, CO, 1972-2005 (adapted from Drewien 2005).

0

2

4

6

8

10

12

14

1972197319741975197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005

(Mean = 7.9%)

% Juveniles
30 

Fall Pre-migration Staging Areas

Staging sites associated with production areas serve as gathering locations prior to fall migration. Necessary 

components of staging habitat are grain fields for feeding in close proximity to roosting sites in shallow 

lakes, marshes, or river bottoms (Drewien and Bizeau 1974). 

Increases in home development and subdivisions are negatively impacting some premigration staging 

habitats in portions of eastern ID, western WY, and southwestern MT. The explosion of subdivisions 

adjacent to the Salt River crane and goose habitat in lower Star Valley, WY, has reached the point where 

it is becoming difficult to conduct an aerial survey. Numbers of cranes and Canada geese using this area 

have declined substantially in recent years. Several other premigration staging sites are following this 

trend (Drewien and Thorpe 2005). 

Migration Stopover Areas

The major fall and spring migration stop for the RMP is in the SLV, Colorado. Most roosting areas are on 

the Monte Vista NWR, (up to 15,000), Higel SWA, Rio Grande SWA, the channel of the Rio Grande and 

private marshes and wet meadows along the river from the town of Monte Vista to the Alamosa NWR. In 

fall, most cranes feed in private, harvested small-grain (wheat, barley and triticale) fields; in the spring, many 

cranes feed on refuge grain fields at Monte Vista NWR. 

Wintering Areas

The primary winter range is the Middle Rio Grande Valley, New Mexico. Cranes roost on sandbars in the 

river near grain fields on private lands, and in the river and managed wetlands on federal refuges and state 

waterfowl management areas (WMAs). Historically, the largest number wintered on Bosque NWR. Since 

1997, the state WMAs and private lands have attracted more cranes, on average wintering 50% of the cranes 

in the MRGV. Smaller numbers winter in similar situations and on playas (closed basins) in other areas in 

New Mexico, southeastern Arizona, and in the Northern Interior Highlands of Mexico, primarily in 

Chihuahua, Mexico. Mexico’s significance for wintering RMP cranes has greatly diminished due to wetland 
31 

drainage in the Galeana Valley and changing crops in the Ascencion Valley and elsewhere (R. Drewien, per. 

comm., Drewien et al. 2003). 

Management and Research

Current Programs

Arizona. In 1996, the Arizona Game and Fish Department (AGFD) acquired a major sandhill crane roost 

site in the Sulphur Springs Valley near McNeal (White Water Draw Wildlife Area). In 2004 the Department 

finished a 40-acre moist soil project to provide food for cranes and waterfowl. Those units are flooded in the 

spring and fall. The AGFD also pumps water to maintain a roost near Willcox (Willcox Playa Wildlife 

Area) when the primary roost (Willcox Playa) is dry. AGFD has also enacted a cooperative agreement with 

a power company near the playa to ensure maintenance of another important crane roost site near the plant. 

With this activity substantial increases in roost sites have been made available for cranes. Production of both 

corn and sorghum present the greatest foraging opportunities for wintering cranes in the Sulfur Springs 

Valley. Changes in agricultural crops to alfalfa and altered management practices such as cutting grain crops 

for silage will reduce areas available for foraging. 

The January count for cranes has increased from 4,300 in 1981 to 29,200 in 2006. In January 2004, a record 

count of over 31,000 was recorded. We speculate that efforts to assure consistent roost sites (addition of 

Whitewater Draw Wildlife Area, pumping water into Wilcox Playa) has short-stopped large numbers of 

cranes from Mexico. There is evidence that some cranes wintering in Arizona use Bosque del Apache in 

New Mexico as a stopover. 

 

Arizona has conducted limited permit, recreational hunts on sandhill cranes each November since 1981. 

Permits, which allow each successful applicant to take 2 cranes per season, are allocated by random drawing. 

During the initial 4 years of the hunt, 100 permits were issued. Permits were increased to 150 in 1985, 300 
32 

in 1987, and 365 in 2005. Total harvest ranged from 42 in 1981 to 277 in 2005. Those harvests include 

MCP Cranes. Mean harvest of RMP cranes since the inception of the hunt is 30 cranes with a high of 61 

RMP cranes harvested in 1993. In 2005, Arizona harvested an estimated 50 RMP cranes. 

Colorado. Greater sandhill cranes were designated by the state as endangered on the nesting range and nongame throughout the remainder of the state. An increasing number of nesting pairs in the early 1990s has 

enabled the population to be down listed from endangered to threatened status. However, production has 

remained below the objective of the state recovery plan and must be improved before complete delisting of 

the population. The Colorado Division of Wildlife (CDOW) continues to work with land management 

agencies and private landowners on improving nesting habitat. Intensive surveys in the nesting range are 

conducted periodically. 

Conditions on fall pre-migration staging areas have improved with The Nature Conservancy’s (TNC) 

purchase of a ranch that includes a portion of a major roost for cranes along the Yampa River near Hayden. 

The cranes still forage in wheat and barley grown on private lands near the roosts. Cranes are counted on the 

fall staging areas in conjunction with the coordinated RMP fall population survey. Age ratios are 

determined periodically on the staging areas. 

Managing habitat to support sandhill cranes is an objective of the Monte Vista and Alamosa NWRs in the 

SLV. At Monte Vista, practices include (1) planting small grains such as barley and wheat which remains 

standing through the fall to discourage use and is mowed in February for spring crane and migratory bird use 

and, (2) water management, often including pumping. Irrigating wet meadows and other wetland types to 

provide foraging and loafing sites as well as providing open water for roosting sites, particularly during 

periods of drought and/or in the spring when most other water in the valley is frozen. 

Additionally, the FWS recently established the Baca NWR, in Saguache and Alamosa counties and has an 

approved acquisition boundary of approximately 92,500 acres. This refuge at the base of the Sangre de 
33 

Cristo Mountains and adjoining TNC’s Medano-Zapata wetlands to the south, has a variety of wetland types 

conducive to sandhill crane roosting, foraging, and resting. Managing for a variety of healthy wetland types 

and conditions is a management priority, which will support the RMP (FWS, Conceptual Management Plan: 

Baca NWR, 2005). It is postulated by many biologists and mangers that wetland and upland habitat 

conditions found on the Baca NWR may best represent those used by cranes in the SLV prior to European 

settlement. Additionally with these habitats now under federal ownership there are excellent management 

opportunities to provide roost sites in the northern portion of the SLV, which may allow for cranes to feed 

on waste grain in private fields that are currently underutilized due to the long distance to traditional roost in 

the central portion of the SLV. It has been found in the SLV that most cranes do not travel more than 7 

miles from the roost to foraging sites. Also management on Baca NWR may be able to provide and support 

the conditions conducive to the production of the “natural” foods cranes utilize versus the agricultural crops 

cranes have become dependent upon in other parts of the SLV. Incidental observations have indicated that 

cranes roosting on the Baca NWR may not leave the area to forage in neighboring farm fields, but are 

perhaps, foraging in refuge habitats. The Baca NWR, as a large, continuous piece of land with a mosaic of 

habitat conditions, may serve as an excellent test, and then opportunity, of being able to feed cranes in nonagricultural habitats. 

Spring food for cranes is becoming a critical issue in the SLV. For one, the amount of waste grain on private 

lands is being reduced by the increase in fall tilling and irrigation of harvested grain fields. Farmers 

implement these practices to encourage the growth and then subsequent freezing of waste seeds to get a 

clean field for subsequent spring planting. Secondly the amount of acres in the small grain production has 

dramatically reduced beginning in the late 1990’s by the replacement of alfalfa. It is unknown how cranes 

will or will not forage in alfalfa fields; incidental observations indicate that cranes may forage on insects and 

other invertebrates in alfalfa fields that are being irrigated. The reduction of waste grain availability in 

spring may be intensifying competition among RMP cranes, an increasing segment of lesser and Canadian 

cranes, and waterfowl populations. In March 1997, the Pacific Flyway Council requested the CDOW and 

FWS to address the issue of spring food supplies for the RMP. 
34 

In a response to the decline in food resources for spring migrating cranes, the FWS leased private farm fields 

around areas of high crane use (north and south of the town of Monte Vista). Farmers were paid by the acre 

to not till and irrigate stubble fields so that waste grain would be available through the fall and spring for 

sandhill cranes. Private farmers willingly participated; however, the funding for these efforts was unplanned 

and opportunistic, and therefore not always available especially during limited budgets. Refuge staff 

collected data on the amount of waste grain present before, during and after spring and fall migrations to 

document use of food by cranes and other migratory birds. In general, between 80-95% of the waste grain on 

leased fields in early September was gone by the end of the next year’s spring migration. 

The FWS’ Partners for Fish and Wildlife Program has actively been promoting the development and 

management of shallow water wetlands on private lands throughout the SLV, but in particular areas 

commonly used by cranes, to provide more roost sites. Wildlife biologists and managers, have assumed that 

one of the limiting factors to dispersing high numbers of cranes throughout the SLV, is the lack of roost 

sites, therefore, the development of these roost sites has been encouraged. Since the development of a few 

private wetlands in the north-central part of the valley, there has been an increase in all migratory waterbird 

use and in particular cranes. It is believed that these cranes are able to forage on nearby wetlands and the 

waste grain in private fields that they would not normally use from more traditional roost sites on the Rio 

Grande to the south. 

Conservation for sandhill cranes is strong for the Natural Resources Conservation Service (NRCS) in the 

SLV because of issues involving changes in agricultural practices, loss of wetlands, and the fact that 

cranes utilize private lands extensively. Through U.S. Department of Agriculture (USDA) programs and 

partnership efforts, NRCS is able to provide technical and financial support to private landowners wishing 

to protect, restore, and manage lands for sandhill cranes. Projects on private lands include; restoration 

and enhancement of shallow wetlands as forage and potential roost sites, lands protection, securing 

unharvested small grain crops during drought, and by providing incentives to agricultural producers to 
35 

incorporate leaving more small grain crop residues into their long-term management operations. 

Eliminating conflicting strategies such as promoting fall tilling and irrigating harvested grain fields to 

germinate waste grain would benefit cranes. 

Through 1996, cranes were censused in spring in the SLV by FWS personnel and the results utilized as the 

best estimate of population size for management purposes. These counts were discontinued in 1997. Early 

fall migrating RMP cranes are counted in the SLV during the coordinated fall count in September. The 

young:adult ratio (recruitment) is estimated for the entire population through classification counts in the SLV 

during late October. Mean recruitment from 1972-2004 is 7.9% (Table 3). Some mortality occurs prior to 

this survey due to hunting in the summer states and hazards during migration. 

Idaho. During the mid-1990’s, eastern Idaho farmers became increasingly intolerant of crane damage and on 

numerous occasions requested relief from the Idaho Department of Fish and Game (IDFG). In the Ashton 

area of Fremont County, damage occurs primarily in spring and summer before September 1. The damage is 

generally caused by family groups rather than large flocks. The crop most frequently damaged is potatoes, 

usually seed potatoes. Small grain crops are also damaged at times, but damage is generally minor. Crop 

damage in the remainder of eastern Idaho typically occurs in late summer and early fall, generally early to 

mid-August until mid-September. Family groups and non-breeders in small to large groups cause the 

damage. The crops most frequently damaged are small grains, mainly barley. Damage can range from very 

minor to severe. 

In July, 1996, the IDFG reclassified the sandhill crane from “protected nongame” to “migratory game bird” 

and established the State’s first recreational hunt using a 20-bird harvest allocation and 30 randomly-selected 

permittees. 
36 

Since 1995, the IDFG has gathered data on summer populations and September staging areas to comply with 

management plan requirements. Since 1996 the IDFG has offered sport hunting seasons with annual harvest 

averaging about 200 cranes. 

Crop damage complaints are serviced by both the IDFG and Wildlife Services. A memorandum of 

understanding directs the IDFG to service minor complaints involving less than 100 cranes between 1 May 

and 15 August, and directs Wildlife Services to service all other complaints. 

The FWS manages approximately 200 acres of grain planted as supplemental feed at Bear Lake, Camas, and 

Grays Lake NWRs to help alleviate crop damage on adjacent private properties. Most often, barley is 

planted as supplemental feed. 

Mexico (Chihuahua and Durango). Details of any specific management practices should be solicited from 

Secretaria del Medio Ambiente y Recursos Naturales (SEMARNAT). Minimal information is available on 

harvest rates of RMP cranes in Mexico. Lafón and Soto (1991) estimated a 2.3% harvest rate among all 

sandhill crane subspecies. At Laguna de Babicora the harvest rate may be 3% but, in other areas, harvest is 

insignificant. Drewien et al. (1996) observed more incidents of subsistence hunting than recreational 

hunting during winter crane surveys from 1970-1993. Local residents attempted to take cranes with rifles 

and pistols making them very wary and more difficult to approach than on winter grounds in New Mexico 

and Arizona. Mid-continent lesser subspecies comprise most cranes wintering in Mexico, and the majority 

of the harvest. On average, 88.9% of the cranes counted on 6 study sites in Chihuahua, Mexico, were 

lessers. Drewien et al. (1996) postulate 25% of the cranes classified as greaters were actually Canadians. 

This means about 8% of the cranes on the 6 study sites may have been greaters. Although the primary 

wintering area in Mexico includes the Northern Interior Highland states of Chihuahua, Durango and 

Zacatecas only small numbers of RMP greaters are found south of central Chihuahua; most occur in 

northwestern Chihuahua near the New Mexico border. Currently, the most important winter site for RMP 

cranes is the Ascension Valley, Chihuahua. Formerly the Santa Maria river valley near Galeana, Chihuahua 
37 

was an important winter area for RMP cranes (Drewien et al. 1996). However in the 1990’s the primary 

crane roost site, a large marsh near Galeana, was drained and only a few cranes currently winter in the area. 

Crane distribution has shifted markedly since the 1950s and early 1960s in response to changing agricultural 

practices and wetland degradation caused by deforestation, overgrazing, water diversions, water pollution, 

and other effects of human population growth (Drewien et al. 1996). Most crane wintering habitats in 

Mexico are vulnerable to further, adverse habitat modifications. In the 1990’s, the Mexican federal 

government proposed to drain much of the Babicora Basin to improve agriculture and flood control 

(Drewien et al. 1996). This important wetland area in west-central Chihuahua supports the highest winter 

concentrations of cranes, primarily lesser subspecies, in Mexico (Buller 1982, Drewien et al. 1996)(0 = 

12,614, range 1,470 – 25,680). From 1995-1998, the University of Chihuahua, with funding and support 

from other partners, developed a conservation management plan for Laguna de Babicora (A. Lafón per. 

comm., Drewien et al. 1996). Currently, the drainage proposal has been deferred. Drainage of this wetland 

would eliminate the most important sandhill crane wintering site in Mexico. 

Montana. Pre-migration staging counts are annually conducted by personnel from Montana Fish, 

Wildlife and Parks (MFWP), the FWS, and private volunteers on occasion. Hunting seasons on the RMP 

were initiated in 1992 and currently include 3 hunt units in the Pacific Flyway portion of the state and 1 

hunt unit in the Central Flyway portion of the state. In 2004, the Dillon hunt area was expanded north 

along the Jefferson River to Whitehall. In recent years, there have been approximately twice as many 

crane-hunting applicants as available permits. 

Intermountain West and Prairie Pothole Joint Venture partners have identified flood plains and other 

wetland habitats as priorities for enhancement and conservation. These ongoing conservation efforts will 

continue to benefit RMP crane breeding habitats. 
38 

New Mexico. Populations of sandhill cranes are monitored by the New Mexico Department of Game and 

Fish (NMDGF) during monthly aerial surveys conducted from mid-October through early January. FWS 

personnel on Maxwell NWR and Las Vegas NWR conduct weekly ground counts monitoring cranes. 

MRGV sandhill crane management is guided by a cooperative agreement, A Plan for the Management for 

Waterfowl, Sandhill Cranes, and other Migratory Birds (MRGV Plan), between the NMDGF, FWS, and 

Wildlife Services. The MRGV Plan goal is maintain a mean monthly population of 17,000- 22,000 

sandhill cranes during November- February. This population level ensures viability within food supplies 

and depredation complaints that are not excessive. The objectives are to maintain a refuge distribution of 

60% of the wintering birds at Bosque NWR and 40% on NMDGF WMAs, and minimize problems 

associated with sandhill crane crop depredations. Weekly ground surveys are conducted by the FWS to 

monitor the population and a FWS aerial survey is conducted in December to assess crop depredation 

potential on private lands (Taylor 1999). In 2005, the FWS aerial survey counted 79% of the MRGV 

wintering crane flocks on federal or state refuges and 21% on private lands. The 1999-2001 MRGV 

mean population was 21,879 wintering sandhill cranes. The 2001 average population was 23,510 cranes 

with a peak count of 32,156 (Mitchusson 2003). The 2005 average population in the MRGV was 20,926 

cranes with a peak count of 27,250. The proportion of sandhill cranes wintering on refuges during 1999-

2001 averaged 50% on Bosque NWR and 50% on NMDGF WMAs (FWS, Bosque del Apache, 2002). 

Flock distribution objectives have not been met since 1989 (Taylor 1999, Mitchusson 2003). The 

proportion of sandhill cranes wintering on refuges during 2005-2006 averaged 57% on Bosque NWR and 

43% on NMDGF WMAs. 

An objective of Bosque NWR is to manage habitat for wintering greater sandhill cranes. Management 

activities include growing about 290 acres of corn and more than 750 acres of alfalfa for sandhill cranes and 

waterfowl. An additional 70 acres are being developed to grow cereal crops. Open shallow water marshes 

are maintained for feeding, roosting and loafing. Moist soil impoundments grow chufa providing another 
39 

food source for sandhill cranes. River roost sites have been recreated through salt cedar removal and 

mechanically widening the river channel. 

Management of agricultural crops on NMDGF WMAs was originally directed primarily at waterfowl. 

Recent management actions have increased the emphasis towards sandhill cranes. The Ladd S. Gordon 

Complex composed of 4 WMAs in the MRGV totals approximately 5,900 acres of irrigated agricultural land 

and wetlands. An annual goal of 1.2 million pounds of grain (primarily corn) are produced on the WMAs to 

provide sufficient food reserves to support wintering cranes and light geese. Wetland developments are 

providing additional crane roost sites. 

An experimental hunting season for sandhill cranes in the MRGV was first conducted during October 1986. 

This experimental hunt has been conducted annually and became operational in 1990. Experimental hunting 

seasons for sandhill cranes in southwestern New Mexico were conducted in 1982, 1983, 1984, 1989, and 

1991-1996. Schmitt and Hale (1997) summarized these hunts. The crane season in southwestern New 

Mexico is operational. An experimental sandhill crane season in the Estancia Valley began in 2001 and 

soon will become operational. Scheduling the southwest and Estancia Valley hunts in late October limits the 

RMP crane harvest while offering sport crane hunting and minimizing crane depredation complaints. The 

majority of the harvest is comprised of MCP lessers taking advantage of peak migration periods prior to the 

arrival of RMP cranes. January southwest hunts have a higher percentage of RMP cranes in the harvest but 

are buffered by the lessers that winter in this region and those returning north from Mexico (Mitchusson 

2003). 

Large numbers of sandhill cranes winter on private lands in the MRGV. Some landowners have tolerated 

crane use on private lands, while others, particularly in the Socorro area, have been quite vocal and have 

filed complaints with Wildlife Services. In 1993, complaints reached an all time high prompting 

congressional response and informal hearings. Annual agricultural damage caused by sandhill cranes in 

the MRGV was in excess of $100,000 per year. As a result, Wildlife Services received funding 
40 

specifically to provide more personnel to answer depredation complaints in the MRGV. Wildlife 

Services personnel use pyrotechnics to disperse flocks and assign crane hunters to private lands with 

depredation complaints. MRGV sandhill crane hunting seasons are scheduled to reduce depredation and 

provide recreational opportunity. These methods along with timed crop manipulations on the refuges are 

used to encourage cranes remain on the refuges and reduce agricultural damage (Taylor 1999). The 

average annual confirmed depredation loss in the MRGV since 1993 is approximately $500 (A. May, 

Wildlife Services, per. comm.). The proportion of sandhill cranes using private lands during 1989-2001 

has ranged from 9% to 35% and averaged 23% (USFWS, Bosque del Apache, 2002). The proportion of 

sandhill cranes using private lands during 2005-2006 was 21%. 

In 2003, the NMDGF developed a state sandhill crane management plan to direct agency activities regarding 

sandhill cranes (Mitchusson 2003). Suitable and potential sandhill crane habitat has not been quantified in 

New Mexico but appears to be declining. Geographic Information Systems (GIS) technology and habitat 

suitability models will be used to obtain this information. 

Utah. The Utah Division of Wildlife Resources (UDWR) annually collects data on crane recruitment, 

summer and fall population numbers, and hunter harvest. Control of crop damage is necessary each year in 

all northern counties and in portions of the Uintah Basin, and supplemental food crops are being planted on 

several UDWR-controlled management areas. Damage is greatest in spring when cranes consume 

germinating corn crops, but some damage occurs to unharvested grain crops in fall. Breeding pairs as well 

as non-breeding flocks are responsible for the damage and are present throughout the summer months in 

most northern Utah counties. 

 

Since 1989, the UDWR has held a crane hunt in Cache and/or Rich counties, with the exception of 1992 

when the Utah Wildlife Board suspended the hunting of cranes for 1 year. In subsequent years the hunt 

expanded into Box Elder and Uintah counties, and interest is growing for a hunt in several central Utah 

counties. 
41 

Wyoming. Since 1982, the Wyoming Game and Fish Department (WGFD) have held a hunting season on 

RMP cranes (Lockman et al. 1987). Hunting, supplemental feed crops, and conventional methods of 

controlling crop damage were evaluated from 1979 to 1984. 

Since 1982, the WGFD has documented and mapped spring, summer, and fall crane distribution. All crane 

observations have been logged using the Department’s computerized "Wildlife Observation System." 

Historically, annual data were collected on distribution, staging area densities, fledged chick recruitment, 

habitat use, harvest, hunter effort, and crane distribution during the hunting season. In recent years, data 

collection has been confined to fall premigration staging surveys and harvest surveys. Pre-migration staging 

counts are conducted by personnel from the WGFD, FWS and private volunteers on occasion. Occurrence 

continues to be documented opportunistically throughout the year. 

Marking studies to determine migration and movements were conducted in cooperation with the Idaho 

Wildlife Research Institute, Moscow. The characteristics of seasonal crane habitats and other data have been 

summarized by Lockman et al. (1986) and Rowland et al. (1992). 

The WGFD initiated an experimental crane hunt in Park and Big Horn counties in fall, 1996. Twenty-five 

permits were made available for the new hunt through a redistribution of permits from 4 existing hunt areas. 

The redistribution did not affect Wyoming’s overall harvest allocation. 

Cranes nesting in Yellowstone and Grand Teton National Parks are passively managed in that their habitat is 

preserved. Surveys were initiated in 1984 to determine the status of birds in these areas. Preliminary 

findings were summarized by Drewien et al. (1987, 2001). 

Wyoming has documented that staging cranes shift their distribution in response to hunting (Lockman 

1988). This behavior is apparently learned over a period of 3-4 years once hunting begins in an area. 
42 

Cranes displace outside the hunt area and move to other staging locations. By the time formal pre-migration 

surveys are done in mid to late September, much of this redistribution has already taken place. Therefore, 

surveys conducted at that time may not accurately reflect the distribution of resident birds in summer range 

states. Thus, additional surveys (possibly pre-hunt) may be required. 

There is concern by some with declining fall staging counts in the Bear River Valley and Star Valley. It is 

believed that the major cause for the decline is due to changes in habitat. The main factor being these areas 

are changing from agricultural to urban use. If flocks continue to decline, permit numbers will be reduced or 

the hunt eliminated in these two areas. 

V. PROBLEMS

Problems affecting RMP cranes vary among regions. The various seasonal habitats continue to be impacted 

from a variety of causes, including housing and industrial developments, changing agricultural practices, oil 

and gas exploration and development, drought, flood control projects, and wetland drainage. Competition 

for limited resources on wintering areas by RMP cranes, high snow and Ross’s goose populations, and other 

crane populations have caused agricultural damage in some regions. Shrinking habitats in fall staging and 

wintering areas, particularly wetland roosting areas, increase the risk of disease outbreaks due to 

overcrowding of birds. Avian tuberculosis, cholera, botulism, and lead poisoning have caused crane 

mortality in wintering areas and in the SLV, Colorado (Kauffeld 1987, Snyder et al. 1987, Drewien et al. 

2001). Hazards, such as transmission lines (Brown et al. 1987, Brown and Drewien 1995, Drewien et al. 

2001) and even stock fences, contribute to annual mortality. While predators may influence recruitment in 

some locations, predation is not considered a significant problem for the population. Increases in population 

densities, whether produced by normal recruitment or forced concentrations of birds due to shrinking 

habitats, contribute to increases in damage to private agricultural crops. Some of these problems are 

alleviated by habitat improvement projects on state and federal lands and through carefully-designed and 

regulated sport hunting programs in the United States' portion of the RMP range. 
43 

More specific problems by state follow: 

 Arizona. With the success in providing roost sites, a potential exists for cranes to damage 

newly-planted grain crops and to exhaust limited supplies. Additionally, there is a shift from 

grains, corn, and sorghum towards alfalfa and cotton. Cranes consume alfalfa only when the 

plants are small; cotton is of no value to cranes. Arizona has implemented a cooperative 

agreement with several local farmers to grow corn and leave stubble for cranes. There remains a 

concern that should agricultural practices change, forage availability could become a problem in 

the future. Under current conditions, roosting habitat is secure, but forage supplies may become 

limiting. 

 Botulism is potentially a problem on the Willcox Playa, the major roost area. A minor outbreak 

occurred in 1980. The Department has attempted to mitigate this problem with additional roost 

areas at Crane Lake (within Wilcox Playa itself) and Whitewater Draw. 

 Colorado. Much of the crane nesting habitat on private land is located in areas that are attractive 

to home development. Programs informing private landowners about the needs of nesting cranes 

must be continued. Crane food supplies on premigration staging areas in northwestern Colorado 

are unstable, limited, and subject to crop depredation. 

The lowering of the water table in the SLV has resulted in loss of foraging wetlands, forcing 

cranes to become primarily dependent on grain crops for nutrition. Fall tilling and irrigation of 

harvested small grain fields in the SLV has reduced the supply of grain available in the spring for 

cranes and waterfowl. Additional food sources may be developed to maintain body condition 

and reproductive potential of cranes returning to nesting areas. 

 
44 

 Idaho. With a major segment of the RMP nesting in eastern Idaho and nearly 40% of the 

population staging there in September, grain and potato farmers are becoming increasingly 

intolerant of damage caused by cranes. Some operators claim farming economics are such that 

they can no longer afford to feed cranes. On numerous occasions, they have requested relief 

from the IDFG as well as the Idaho Congressional delegation. Urban development in the Teton 

Basin, Teton County, is consuming habitat traditionally used by RMP cranes; this is reducing the 

area’s capacity to support summering and staging cranes and is increasing the potential for crop 

damage complaints. In addition, crane use of the Grays Lake NWR has declined over the past 

10-15 years because of changes in habitat management. This decline in crane use contributed to 

crop damage problems in the Blackfoot Reservoir area in the 1990’s. 

 

 Mexico. Additional information for this section should be solicited from SEMARNAT. Crop 

damage during the winter period may be a problem. Though potential excessive subsistence and 

recreational harvests of cranes is unlikely, better harvest information is desirable. The loss of 

wetland habitats is likely to continue and increase from a variety of land developments. 

Principle causes of wetland degradation throughout Mexico include water diversions, pollution, 

deforestation, overgrazing, and other effects associated with human population growth (Drewien 

et al. 1996, 2003). The greatest threat could be the proposal by the Mexican government to drain 

much of the Babicora Basin in west-central Chihuahua, the most important crane wintering 

location in Mexico. Babicora Basin’s importance is greatest for the lesser subspecies. However 

loss of this wetland would eliminate potential use by RMP greaters. The Galeana area in 

northwest Chihuahua was formerly an important RMP winter area during the 1970’s-90’s 

(Drewien et al. 1996). The primary roosting wetland was recently drained, resulting in greatly 

reduced crane use of this winter site. 

 

 Montana. Damage to unharvested cereal grain crops can be significant, especially in the vicinity 

of the higher-elevation pre-migration staging areas where harvest is often delayed until 
45 

September. Breeding areas especially in intermountain valleys are experiencing increased 

urbanization and subdivision encroachment. This results in additional power lines and greater 

potential for aerial collisions. 

 New Mexico. Increasing urbanization, changes in agricultural crops and water management 

have negatively impacted sandhill crane habitat. Urban development in portions of the 

MRGV from Los Lunas to San Antonio has eliminated many winter sites and more will be 

lost in the near future. In 2006, an important agricultural winter site near Los Lunas was sold 

and will be converted to housing. This property supported up to 1000 cranes and 7100 geese. 

These birds will be forced to use crowded state or federal refuges. As habitat is lost wintering 

cranes and waterfowl are restricted to fewer areas. Food supply and overcrowding are 

becoming priority concerns for population maintenance. Houses built on the MRGV 

floodplain now prevent the very large spring flows necessary to scour the riverbed and alter 

the river channel to maintain suitable unvegetated roost sites. As lands are converted from 

agricultural uses to urban areas more hazards for sandhill cranes in the form of power lines 

and fences will be created. Currently, urbanization does not pose as large threat to the other 

wintering areas, but there is the potential conflict as agricultural lands and water supplies are 

diverted from agricultural practices to urban uses. 

Use of the San Acacia Diversion Canal has resulted in loss of roost habitat on the Rio Grande, 

which affects winter distribution of cranes. During many years this diversion plus irrigation 

demands de-waters the Rio Grande. Increasing water conflicts between urban, agricultural, 

interstate stream compacts and endangered species management, such as the silvery minnow 

(Hybognathus amarus); especially during drought periods, can adversely impact crane 

habitats. Without the regular high flows to scour river vegetation, roost sites become 

overgrown concentrating birds into fewer open areas. Spring floods occurred in 2005 

improving crane roost sites in the MRGV. 
46 

 Periodically depredations by cranes have been severe in Valencia, Socorro, Sierra, Dona Ana, 

and Luna counties. As habitat is lost and wintering waterfowl and cranes are restricted to fewer 

areas, food supply and overcrowding are becoming priority concerns for population 

maintenance. Changes in crop patterns in most locations has reduced feeding habitat in New 

Mexico (less grain and more alfalfa, cotton and chile). 

 Utah. Urban expansion along the Wasatch Front, Cache and Summit counties continues to 

consume natural and agricultural habitats important to breeding and staging crane populations. 

Depredations on remaining agricultural areas are consequently growing in some areas and 

tolerance for cranes can be problematic. 

Wyoming. RMP cranes stage near several agricultural projects in central and western Wyoming 

during late summer to early fall, where crop damage can be a problem. The damage is often 

compounded by feeding activities of RMP Canada geese that also congregate in the same areas. 

Controlled hunts in September effectively disperse cranes and geese from grain fields. However, 

new damage situations occasionally arise as agricultural practices change and crane distribution 

shifts. 

 Agricultural interests have voiced concern about fall crop damage by RMP cranes in all hunt 

areas and the Bridger Valley. Food resources in pre-migration staging areas are limited and 

therefore crop depredations occur. Expansion of barley production in the Farson-Eden area, the 

last 7 years, has not resulted in an increase in crop damage by cranes and geese. Staging by 

several hundred to a thousand cranes along the Greybull and Shoshone Rivers in Park and Big 

Horn counties is a fairly recent development, which has caused some crop damage complaints in 

that region. During the last decade, the Boysen-Riverton area had the highest number of crop 

depredation complaints. . Except on the Ocean Lake Habitat Unit, the WGFD does not plant 
47 

supplemental feed to attract cranes or geese away from private grain fields. Farm operators 

continue to request additional permits and longer seasons to alleviate crop damage. Damage to 

newly planted row crops in the spring is a more difficult issue, which cannot be addressed by 

controlled hunting seasons. 

Valley floor development throughout Wyoming seriously threatens many of the State’s most 

limited and important wildlife habitats. Ongoing development in the Star Valley has impacted 

preferred crane roost sites. The explosion of subdivisions in the lower Star Valley, has reached 

the point where it is becoming difficult to conduct an aerial survey. Numbers of cranes using 

this area have declined substantially in recent years (Drewien and Thorpe 2005)(see Table 1). 

VI. RECOMMENDED MANAGEMENT PROCEDURES

The following management procedures are recommended. The degree and timing of their implementation 

by the various lead agencies will be influenced by manpower and fiscal and legislative constraints beyond 

the scope of this plan. Whenever possible and appropriate, plans for other species and populations of Pacific 

and Central Flyway birds should also consider the management procedures in this plan. Improved 

coordination between state and federal refuges throughout the region would greatly enhance sandhill crane 

management. 

Habitat

1. Habitat Conservation. Maintain and enhance important crane habitats as follow: 

 Arizona. Work with local landowners to assure that sufficient forage remains available for the large 

wintering population of sandhill cranes in the Sulfur Springs Valley. 

 Lead agencies: AGFD. 
48 

 Priority: high. 

 Schedule: Ongoing. 

 Colorado. In recent years, changing agricultural practices in the SLV have diminished small grain 

availability and increased competition among the RMP, other crane subspecies, and waterfowl during 

the spring migration period. There is concern limited food supplies may impact body condition and 

reproductive potential of RMP cranes returning to their summer range. A baseline study conducted 

during 1997-2001 indicated that waste grain abundance on fields with typical post-harvest practices is 

substantially lower than on fields left in stubble (5.97 kg/ha versus >200 kg/ha), but RMP cranes 

appeared to gain fat reserves during the spring stopover period in the SLV (Gammonley and Laubhan, 

in review). The Councils encourage further investigation of this problem, including the extent to 

which limited food resources may be impacting maintenance and growth of the population. Another 

component of this research may include investigating the feasibility of augmenting food supplies by 

developing natural forage sites through wetland creation and enhancement. Increasing acreages of 

small grain production on refuges would augment diminished food availability on private lands. 

 

Lead agencies: RMP Crane Subcommittees. 

 Participating: FWS, Monte Vista NWR, CDOW, academic institutions, and consultants with 

applicable expertise. 

 Priority: high. 

 Schedule: Continuing. 

Communicate with local NRCS offices regarding their recommended farm practices on 

private grain fields. If appropriate or feasible, recommend that some fields in high crane 

use areas be encouraged to not till and irrigate fields after fall harvest to allow for adequate 

amounts of waste grain on soil surface through fall and early spring migration. 
49 

FWS, CDOW, NRCS, and other natural resource agencies continue to communicate and 

collaborate on habitat management techniques and conservation actions that support 

sandhill crane habitat. These techniques include; providing a mosaic of roost sites 

throughout the SLV to encourage a wider distribution of cranes throughout, and the 

production of foods in wetland and upland habitats to potentially offset current foraging 

dependency on small grains. 

Continue to work with local utility companies to mark power lines to reduce lethal crane 

strikes. Of special concern recently developed shallow-water wetlands developed on 

private lands through the FWS’ Partners Program and other agencies that then provide 

roost sites. 

During range-wide drought when it is probable that waste grain supplies are limited, seek 

funding to lease stubble fields from private farmers to provide for waste grain. 

Lead agencies: FWS, CDOW and NRCS 

Provide about 500 acres of wet hay meadow and grain fields along the Yampa and Elk rivers in Routt 

County to ensure adequate staging and foraging habitats. 

 Lead agencies: FWS and CDOW. 

 Participating: Other state and federal agencies and citizen organizations will be invited to participate. 

 Priority: high. 

 Schedule: In progress. 
50 

Monitor new and/or underutilized habitats in the northern and southern portions of the SLV. 

Lead agencies: FWS and CDOW. 

Participating: Other state and federal agencies and citizen organizations will be invited to participate. 

 Priority: high. 

Schedule: In progress. 

 Idaho. The IDFG, in cooperation with other state and federal agencies, nongovernmental 

organizations, and private parties, will work to annually provide 600-1,000 acres of supplemental feed 

crops in strategic locations to help alleviate crop damage. Funding for this program will come 

primarily from the interest earned by a Lure Crop Endowment established from private contributions. 

The IDFG, in cooperation with other agencies, nongovernmental organizations, and Teton County, 

will work to protect remaining crane habitat, including roosting sites, loafing sites, and feeding areas 

along the Teton River to alleviate depredations and provide adequate staging habitat. 

 Lead Agencies: IDFG and FWS. 

 Participating: Other state and federal agencies, nongovernmental organizations, and private parties. 

 Priority: high. 

 Schedule: Ongoing 

 Mexico (Chihuahua). Specific habitat needs or surveys to ascertain those needs should be identified 

through consultation with SEMARNAT. Four lagunas in the Ascension Valley, Chihuahua are of 

particular importance to wintering RMP cranes and deserves special protection. Wetland drainage in 

the Santa Maria River Valley near Galeana, Chihuahua has virtually eliminated this area’s importance 

as crane habitat. A recent effort was developed by the University of Chihuahua, with funding and 

support from other partners, to improve and operate a conservation management plan for Laguna de 

Babicora (A. Lafón per. comm., Drewien et al. 1996). Laguna de Babicora importance is primarily 
51 

for the lesser subspecies, but is used by limited numbers of RMP greaters. The subcommittees support 

this effort. 

 Lead Agencies: SEMARNAT, University of Chihuahua, FWS and PROFAUNA A.C.. 

 Participating: RMP Crane Subcommittees, nongovernmental organizations, and private parties. 

 Priority: high. 

 Schedule: Ongoing. 

 Montana. Work through the Intermountain and Prairie Pothole Joint Ventures, utilizing a variety of 

wetland protection and enhancement strategies to conserve and improve wetland complexes used by 

breeding cranes on both private and public land. Work with private landowners in the areas of the 

major premigration staging sites and implement strategies designed to reduce depredation problems 

when they occur. A majority of the crane habitat occurs on private land and trends in federal farm 

programs, intensity of agricultural activities, and urban development will in large measure determine 

long-term trends in crane numbers. 

 Lead Agencies: MFWP, FWS Partners for Fish and Wildlife 

 Priority: high. 

 Schedule: Ongoing 

 

New Mexico. Protect crane habitat, including river sandbars, Bosque (riparian wooded areas), and 

well-drained irrigable cropland to perpetuate objective levels of use by cranes in the MRGV. Create 

additional roosting habitat on NMDGF WMAs and Bosque NWR. 

 Encourage water management agencies to allow occasional high flows in the Rio Grande to benefit 

roost sites and keep water in the riverbed instead of the San Acacia Diversion Canal. Siltation of 

Elephant Butte Reservoir in the future could preclude crop production on the Bosque NWR because of 
52 

a rising water table, and could reduce the area's importance to cranes. The latest drought and resulting 

low lake levels has reduced this potential problem. 

 Obtain maximum production of wildlife crops on NMDGF and federal agricultural lands. Investigate 

possible acquisition of additional agricultural lands and irrigation water rights to offset loss of habitat 

to urban expansion. Encourage programs that promote grain production on private lands. Continue to 

coordinate activities between federal and NMDGF properties in the MRGV. 

Identify and quantify the amount and distribution of current suitable and potential sandhill crane 

habitat to protect and/or manage in order to support desired crane population goals. 

Control non-native invasive vegetation to promote native wetland conditions suitable as crane habitat. 

Lead agencies: FWS, NMDFG, NRCS, BoR, Middle Rio Grande Conservancy District and N.M. 

State Forestry. 

 Participating: Other state and federal agencies and citizen organizations will be invited to participate. 

 Priority: high. 

 Schedule: Ongoing 

 Utah. Through acquisitions, easements, or lease agreements, protect 500 acres of farmland along the 

Bear River in Rich County and an additional 500 acres in Cache Valley to provide staging and 

breeding habitat. Lead agencies will be responsible for identifying habitat presently important to 

cranes and locating willing sellers or those willing to enter into cooperative agreements to protect 

these lands. 

 Continue to provide cereal and food crops on state managed-wildlife areas in Cache, Box Elder, 

Weber and Salt Lake counties. Continue to coordinate with Wildlife Services and the agricultural 
53 

community to provide technical advice on dealing with depredation. Develop and improve the 

farming programs at Ouray NWR to provide habitat during spring and fall for migrating cranes and 

waterfowl. Protect key crane habitat in the Jensen area through land acquisition, cooperative 

agreements, and participation in local government planning activities. 

 Lead agencies: FWS, Wildlife Services and UDWR. 

 Participating: Other federal and state agencies and citizen organizations will be invited to participate. 

 Priority: high. 

 Schedule: Ongoing. 

 Wyoming. Protect sufficient habitat on primary fall premigration staging areas, including roosting 

sites, loafing sites, and feeding areas to support 4,000 - 6,000 cranes. These areas include the Salt 

River, lower Bear River, Farson-Eden Agriculture Project; the Wind River Irrigation Project; the 

Shoshoni River in Park County, and the Greybull River in Big Horn County. This should be 

accomplished in cooperation with private landowners, county planning groups, etc. 

 Provide sufficient grain croplands annually on the WGFD’s Ocean Lake Wildlife Habitat 

Management Unit to support 600-1,000 sandhill cranes in the fall premigration staging period (August 

10-October 25). 

 In cooperation with private landowners, FWS and WGFD, develop a long-term strategy to protect and 

enhance wetlands on the lower Bear River and Salt River for crane production and staging, and 

continue to support development of Cokeville Meadows NWR on the lower Bear River. 

 Utilize recreational hunting to regulate crane numbers and to minimize fall depredation to private 

croplands. 
54 

 Lead agencies: FWS and WGFD. 

 Participating: Other federal and state agencies and citizen organizations will be invited to participate. 

 Priority: high. 

 Schedule: Ongoing. 

2. Inventory of Habitat. Encourage to identify, classify, rank, and catalog habitats used by the RMP 

throughout its range to facilitate the protection of important habitat through acquisition, easement, 

cooperative agreements, special-use permits, and mitigation exchanges and developments. 

Classification would include but not be limited to amount and quality of habitat, spatial distribution, 

relative importance, potential for enhancement, land use and ownership, and threats to continued 

suitability of habitat. Rationale should be developed to prioritize protection of specific parcels of 

lands. All interested agencies, groups, and individuals should be encouraged to participate in this 

effort. Currently, there is such an investigation being conducted by T. Perkins and L. H. Fredrickson 

evaluating RMP crane habitat conditions along the Intermountain West. This study’s goal is to 

understand changes in the availability, distribution, and nutrient characteristics of wetland and 

agricultural habitats important to RMP cranes for foraging, loafing and roosting throughout their 

annual cycle. The focus of this study will be on habitats in Idaho, Colorado, New Mexico and 

Mexico’s Northern Highlands. 

 Lead agencies: FWS, SEMARNAT and state wildlife agencies. 

 Priority: high. 

 Schedule: Ongoing. 

Uses of Cranes

1. Interpretive Program. Observing greater sandhill cranes is an important recreation throughout the 

birds' ranges. “Crane festivals” are attended by thousands of people annually at several staging 

locations including Socorro, NM in November, Willcox, AZ in January and Monte Vista, CO in 
55 

March. Promoting increased awareness and understanding of cranes is essential to the well being of 

the RMP and is therefore an integral part of this plan. Individual state wildlife agencies and the FWS 

will cooperatively develop and distribute information on the life history of RMP cranes and important 

management issues. 

 Lead agencies/groups: State wildlife management agencies and FWS. 

 Priority: moderate. 

 Schedule: Ongoing. 

2. Hunting (harvest allocation and guidelines). In addition to the other uses of RMP cranes, it is 

biologically feasible to allow recreational hunting. The population is hunted annually in Arizona, 

Idaho, Mexico, Montana, New Mexico, Utah, and Wyoming (Table 4 and Appendix A). In Mexico, 

subsistence and recreational hunters pursue cranes. Recreational hunting is allowed only in registered 

UMAS (Unidad de Manejo para la Conservacion de Vida Silvestre – Management Unit for 

the Conservation of Wildlife). 

 Fall pre-migration staging areas, fall migration stopover areas, and selected wintering areas provide 

the best opportunities to harvest cranes and are locations where hunting can help alleviate crop 

damage problems. Hunting can direct harvest at specific segments of the local population that damage 

crops. Any state within the range of the RMP may choose to hunt cranes provided the hunts meet the 

conditions of this plan. 

 Recreational hunting of the RMP will be permitted when the fall population index exceeds 15,000. A 

conservative harvest allocation is prescribed when the fall population index is between 15,000 and 

18,000 cranes to allow for population growth. If the fall population index is less than 15,000, hunting 

may be permitted to meet specific management objectives, including alleviation of localized crop 

damage and distribution concerns. The fall population index will be the average of the 3 most recent, 
56 

reliable surveys (Objective A) conducted on September pre-migration staging areas in Colorado, 

Idaho, Montana, Utah, and Wyoming. 

 Because portions of the RMP range overlap with other subspecies, strategies intended to harvest RMP 

cranes will result in the harvest of other subspecies at some locations. States hunting mixed 

populations will estimate the racial composition of the hunted population based on measurements of 

wing chord, tarsus, and posterior nares to bill tip of harvested cranes (Schmitt and Hale 1997) or other 

appropriate methods. Other subspecies harvested will not be included in the RMP allocation described 

in this plan. States may monitor the racial composition of the harvest once every 3 years in 

operational hunt areas, and use that data for estimating the racial composition in the subsequent 2 

years. States that consider all harvested cranes in a hunt area as RMP greaters are not required to 

monitor racial composition. 

 The allowable annual harvest of RMP cranes will be calculated and allocated among hunting states 

based on the following procedure: 

 a. The total allowable harvest for the entire population will be based on the formula: 

 H = C x P x R x L x f 

 where: 

 H = total allowable harvest; 

 C = the average of the 3 most recent, reliable fall population indices. The fall 

population index will be the fall pre-migration staging survey (Colorado, 

Idaho, Montana, Utah, and Wyoming); 

 P = the average proportion of fledged chicks in the fall population in the SLV 

during the most recent 3 years for which data are available (see Appendix 

A); 
57 

 R = estimated recruitment of fledged chicks to breeding age (current estimate is 

0.5); 

 L = retrieval rate of 0.80 (allowance for an estimated 20% crippling loss based 

on hunter interviews); and 

 f = (C/16,000)3

 (a variable factor used to adjust the total harvest to 

 achieve a desired effect on the entire population -- see Appendix D) 

 This formula will be reviewed every 2 years by the Subcommittees and revised as needed. It 

may require periodic adjustments based on practical application and accumulated data. The 

Subcommittees may seek alternate methods to determine the base allocation. 

 b. The allowable harvest will be allocated among states based on approximate, relative abundance 

by seasonal range as follows: 

 1) Summer range states - 55%, to be divided as follows: 

 % of Summer Allocation % of Base Allocation 

 Alberta (potential) 0% 

 Colorado 5% 2.7% 

 Idaho 40% 22.0% 

 Montana 26% 14.3% 

 Utah 12% 6.6% 

 Wyoming 17% 9.4% 

 Any allocation not used by a state will be made available to summer range states. 
58 

 2) Winter range and migration stopover states - 45%, to be divided as follows: 

 % of Winter Allocation % of Base Allocation 

 Arizona 13% 5.8% 

 Colorado (SLV) 13% 5.8% 

 New Mexico 62% 28% 

 Mexico 6% 2.7% 

 Utah 6% 2.7% 

Any allocation not used by a state will be made available to winter range and migration 

stopover states. 

 

 3) This allocation will be reviewed every 5 years by the Subcommittee and revised as 

needed. 

 The Subcommittees evaluated the crane harvest allocation in March 2006, using 5 

consecutive years (2001-2005) of fall pre-migration data. 

 Wyoming has documented that staging cranes shift their distribution in response to 

hunting (Lockman 1988). This behavior is apparently learned over a period of 3-4 years 

once hunting begins in an area. Cranes displace outside the hunt area and move to other 

staging locations. By the time pre-migration surveys are done in mid- to late September, 

much of this redistribution has already taken place. Therefore, surveys conducted at that 

time may not accurately reflect the distribution of resident birds in summer range states. 

Thus, additional surveys (possibly pre-hunt) may be required to adjust harvest allocations. 

The Subcommittees will investigate other methods to derive an unbiased assessment of 

crane distribution for harvest allocation. 
59 

 c. Prior to the Subcommittee's approval of a state's first hunt for an area, the requesting state must 

provide, where applicable, at least 3 consecutive years of data (usually, the most recent 3 years) 

on RMP numbers in the proposed hunt area, The state must demonstrate a commitment to 

continued monitoring of pre-migration, staging and winter areas. 

 d. The following information for hunting seasons must be collected and reported to the 

Subcommittees at the March meeting following each hunt: 

 1) Number of cranes harvested; 

2) Racial composition of the harvest (Schmitt and Hale 1997) unless all harvest is considered 

RMP; 

 3) Age composition of the harvest; 

4) Crippling-loss rates (number of cranes lost/[number of cranes lost + retrieved]). 

Crippling loss will be defined as cranes knocked down, but not retrieved.

 5) Number of hunters participating; 

 6) Number of hunter days; 

 7) Hunter success rate; and 

 8) An assessment of the effectiveness of the hunting season. 

 

 e. Hunting will be permitted in the states of Arizona, Colorado, Idaho, Montana, New Mexico, 

Utah, and Wyoming. State hunting seasons must: 

1) Be between September 1 and January 31; 

 2) Have a daily bag limit not to exceed 3 cranes; 

 3) Be permitted only on a limited quota (permit) basis; 

 4) Be consistent with the goals, objectives, and harvest allocations identified in this plan; and 

5) Be approved by both the Central and Pacific Flyway councils. 
60 

 f. A state requesting a new hunting seasons, major changes in an existing season, or changes that 

would affect the harvest allocations identified in this plan, must notify the Subcommittees, 

Pacific Flyway Study Committee, and Central Flyway Webless Migratory Game Bird Technical 

Committee (CFWMGBTC) in writing of its intentions at least 30 days prior to the 

Subcommittee's March meetings. 

 h. At the annual March meeting of the RMP Crane Subcommittees, the total allowable harvest and 

the allocation by state for the coming hunt season will be determined using the formula and 

criteria presented above. The allocation will become a permanent record (Appendix A and 

meeting minutes). 

 Lead agencies: FWS and states. 

 Priority: high. 

 Schedule: Develop proposals and initiate seasons as appropriate 
61 

Table 4. Annual RMP Greater Sandhill Crane Base Allocation and RMP Harvest. 

Year Base AZ ID MT NM UT WY TOTAL

Allot.* 

1981 20 20

1982 9 143 152

1983 35 154 189

1984 33 101 134

1985 40 138 178

1986 23 195 218

1987 60 190 250

1988 40 310 128 478

1989 800 51 483 54 125 713

1990 374 9 79 35 58 181

1991 800 44 47 48 101 240

1992 800 39 42 147 168 396

1993 780 61 45 297 28 115 546

1994 864 27 40 416 34 150 667

1995 547 33 41 270 27 77 448

1996 545 27 20 49 236 32 84 448

1997 632 22 136 62 114 30 82 446

1998 693 37 135 59 180 34 93 538

1999 974 21 190 71 198 54 124 658

2000 1141 37 193 91 257 69 163 810

2001 1175 26 278 87 288 77 142 898

2002 833 42 194 51 160 60 132 639

2003 668 34 146 50 169 57 72 528

2004 656 35 142 51 189 53 124 594

2005 906 50 189 49 236 62 116 702

2006 1321 

* Includes Mexico’s portion of the base allotment. 
62 

Crop Damage Control

The Subcommittees will consider problem situations and recommend options to the appropriate state 

agencies for reducing or eliminating crop damage. Various individuals, nongovernmental organizations, and 

other agencies will be encouraged to suggest solutions. Options include: 

1. Hunting Seasons. Hunting seasons should be conducted in a manner that will either reduce the 

number of cranes to management plan objective levels or harass problem cranes from areas of damage 

to areas where either damage is tolerated, food is specifically provided for cranes, or both. Hunting to 

control specific damage problems will be allowed even when the population index is below 15,000 

birds; these hunts must be designed to relieve a specific problem and where necessary, coordinated 

among the states for effective dispersal. Limited quota permits will be required and issued for use 

only in those specific locations where hunting is desired. All other criteria previously detailed for 

"hunting" must be followed. Closely-regulated, hunting has been used effectively in Wyoming since 

1982 to manage cranes and Canada geese causing crop damage (Lockman et al. 1987). Regulated 

hunting has greatly reduced depredation complaints in New Mexico. The timing of season dates and 

assistance from Wildlife Services personnel placing hunters in areas experiencing crane depredations 

reinforces hazing programs and encourages crane movements onto state and federal refuges 

(Mitchusson 2003). 

2. Supplemental Feed Crop and Direct Feeding Programs. Use of supplemental feed crops (strategically 

located crops planted specifically as crane food) or directly feeding grain to cranes, either in 

conjunction with or without hunting seasons, can effectively reduce crop damage. State and federal 

refuges can have a major role towards contributing increasing grain crops for crane use. These 

programs are effective when used in conjunction with hunting seasons, hazing, harassment, etc. or 

when other methods are infeasible. 
63 

3. Hazing and Harassment. Aircraft, explosive devices, or other deterrents may be used to move birds 

from croplands and adjacent roost sites. 

4. Habitat Manipulation. In certain situations, it may be possible to encourage landowners to change 

farming practices to reduce the attractiveness of crops to cranes, eliminate roosts, or make crop 

plantings available for cranes near roosts. Application of proven methods should be used in order to 

predict and alleviate problems. 

5. Extension Services. State and federal agencies, in cooperation with key stakeholders, may find it 

beneficial to provide field demonstrations of methods available to reduce crop damage by cranes. 

 6. Lethal Control. Hunting is a management alternative that is available to every state in the range of the 

RMP. The available harvest allocation is very limited, even during years of high recruitment, and 

public demand exceeds the availability of permits in all states that hunt cranes. Therefore, the 

Councils believe the harvest allocation should be used to meet the public’s demand for sport hunting. 

Permits for hunts must be distributed to the public through a random process. Non-lethal management 

alternatives are outlined in options 2-5 to help alleviate crop damage problems in states that for 

political or social reasons choose not to implement hunts. Other lethal control must be consistent with 

the following: 1) Depredation control programs are subject to RMP sandhill crane management plan 

objective levels and should include consultations with all affected agencies and stakeholders within 

the RMP sandhill crane range; 2) Public hunting is the preferred method of population control for 

reducing agricultural depredation; 3) When public hunting is not possible and non-lethal control 

options have been exhausted, other lethal control methods should be implemented. Other lethal 

population reduction methods should be determined on a case-by-case basis. 

 
64 

Population Surveys

1. Annual Recruitment Survey. Young:adult ratios are obtained each October in the SLV, Colorado, by 

ground surveys. Since 1972, the survey has been done by R. Drewien, who is reimbursed from Pacific 

Flyway funds. Survey methods are described in Drewien et al. (1995). Additional personnel should 

be trained to conduct this survey. 

 Lead agencies: FWS. 

 Priority: high. 

 Schedule: Annually. 

2. Fall Population Survey. Population surveys are to be done each September when peak numbers of 

cranes are present on pre-migration staging areas in summer range states. These fall surveys replaced 

the spring survey in the SLV to measure population trends. The average of the 3 most recent, reliable

surveys, described in Objective A, will be used in the harvest allocation formula. 

 The September survey will be done from both the air and ground, as appropriate, during a 5-day 

window between 5-25 September each year, as identified by the FWS consultant count coordinator. 

An effort will be made to complete the count during 3 consecutive days within the 5-day window. If 

conditions prevent a state cooperator from meeting this schedule, counts must be completed as soon 

thereafter as conditions permit. The 5-day window will be timed to obtain the maximum count 

possible and generally prior to any substantial crane movement from staging areas. The FWS will 

assign its Flyway Biologist and Division of Migratory Bird Management (DMBM) aircraft to conduct 

the survey over assigned staging areas. Cooperating states will conduct counts on the remaining 

staging areas during the same period. A qualified consultant will be retained by the DMBM, to assist 

the FWS biologist in conducting aerial surveys. The consultant’s costs will be reimbursed from the 

FWS Administrative Fund. 
65 

 The FWS crew will schedule the 5-day survey window by mid-August based on an evaluation of 

habitat conditions, breeding season chronology, climatic patterns, weather forecasts, and crane 

movements. The FWS’s Flyway biologist will contact each state and specify the count period at the 

earliest possible date, but not later than 2 weeks prior to the survey. An effort will be made to select a 

3-day target period within the 5-day window. States are encouraged to make an effort to count RMP 

cranes outside the identified staging areas to locate additional concentrations and to address 

distribution shifts, provided such surveys are also conducted within the 5-day count window. 

 The Flyway biologist will maintain a current list of state contacts for this crane survey. Unless 

indicated otherwise, these contacts shall be the respective Subcommittee members representing the 

cooperating states. State cooperators will forward results of any surveys they conduct to the FWS 

Flyway biologist by 30 September each year. 

 Lead agencies: FWS and all states with breeding cranes. 

 Priority: high. 

 Schedule: Annually. FWS will report to the Subcommittees by 1 December each year. 

 Staging areas to be surveyed annually are listed below. Areas designated for coverage by the FWS aerrial 

survey crew are underlined. Surveys in the remaining areas are the responsibilities of the states, FWS refuge 

personnel and other cooperators. 

3. Funding. The costs of the FWS portion of the fall pre-migration survey are shared among the FWS and states 

with RMP cranes. The FWS pays for an airplane and one pilot/observer. A consultant is retained by the FWS 

to assist with aerial surveys, ground counts, and data compilation. The consultant’s costs are paid from the 

FWS Administrative Account. 
66 

 States with assigned coverage areas during the fall pre-migration staging counts pay for their own 

personnel and equipment costs to complete the surveys. A consultant is retained by the Pacific 

Flyway Council to conduct the October recruitment survey and data compilation. The consultant’s 

costs are negotiated periodically and paid from the Pacific Flyway Administrative Account. 

Colorado Montana Wyoming 

 

Lower Elk River 

 Blackfoot/Ovando ValleyHelmville

 Baggs 

Yampa Valley (includes Hayden) Cascade-Ulm Bear River Valley

Delta Co. - other Centennial Valley Greybull River/Otto 

(Fruitgrower's Res.\Hart's Basin, Delta Co.) Deadman’s Basin Shoshone River/Ralston 

San Luis Valley Dillon-Twin Bridges Big Piney

 Gallatin Valley- includes Belgrade Bridger Valley 

 Helena Valley Farson

 Melville Hams Fork

Idaho Musselshell River - inc. 

Harlowtown

 Pinedale-Cora

 Otter Creek Seedskadee NWR 

Amer. Falls Res. Teton River-Eureka Res. Saratoga (Upper N. Platte Valley) 

Ashton-St. Anthony Toston-Townsend Jackson Hole 

Bear Lake Valley Upper Madison Valley – inc. Ennis Star Valley (Salt River)

Blackfoot Res. Warm Springs Hidden Valley (Boysen-Riverton)

Camas NWR White Sulphur Springs Ocean Lake 

Camas Prairie Whitehall Riverview Valley 

Carey Lake area 

Chesterfield Res. Utah 

Grays Lake NWR 

Henrys Lake Flats Cache Co. 

Island Park Res. Box Elder Co. 

Kilgore Davis Co. 

Market Lake WMA Weber Co. 

Marsh Valley Bear River Valley (Rich Co.) 

Mud Lake WMA Round Valley (Rich Co.) 

Oxford Slough-Swan Lake Summit Co. 

Silver Creek Jensen (Uintah Co.) 

Teton Basin Pelican Lake area (Uintah Co.) 

 Leland Bench (Uintah Co.) 

 Morgan Co. 

 

 
67 

Research

As appropriate, the Subcommittees will develop research proposals, recommend needed research, and 

review research proposals. In these actions, the Subcommittees will give priority to research conducted on 

the RMP or regional flocks/subpopulations, rather than local projects. If sufficient resources are available, 

the flyway councils, on recommendation of the Subcommittees, may help fund such research. 

1. Refinement of Adult and Juvenile Survival Estimates. Recruitment of fledged colts to breeding age is 

an important component of the formula used to calculate allowable harvest. The current figure, 0.5, is 

an approximation based on limited data. The Council encourages development of a more accurate 

recruitment estimate and better documentation based on an analysis of historic banding and color 

marking data. 

 Lead agency/group: RMP Crane Subcommittees. 

 Participating: FWS, academic institutions, and consultants with applicable expertise. 

 Priority: High. 

 Schedule: Continuing. 

2. Spring Food Supplies and Wetland Availability in the SLV. In recent years, changing agricultural 

practices in the SLV have diminished food availability and increased competition among the RMP, 

other crane subspecies, and waterfowl during the spring migration period. There is concern limited 

food supplies may impact body condition and reproductive potential of RMP cranes returning to their 

summer range. Research indicates this currently is not a problem (Gammonley and Laubhan, in 

review). The Councils encourages further investigation of this problem, including the extent to which 

limited food resources may be impacting maintenance and growth of the population. Another 

component of this research may include investigating the feasibility of augmenting food supplies by 

developing natural forage sites through wetland creation and enhancement. 
68 

 Lead agency/group: RMP Crane Subcommittees. 

 Participating: FWS, Monte Vista NWR, CDOW, academic institutions, and consultants with 

applicable expertise. 

 Priority: High. 

 Schedule: Continuing. 

3. Techniques for Controlling Crop Damage. The Subcommittees encourages development and testing 

of techniques that will reduce or eliminate crop damage by cranes. If sufficient resources are 

available, the Subcommittees may help fund such research. 

 Lead agencies: Wildlife Services. 

 Participating: States having depredation problems. 

 Priority: high. 

 Schedule: Continuing. 

VII. ANNUAL REVIEW OF PLAN AND REPORTING

The Subcommittees will meet annually or as needed to review progress toward achieving the goals and objectives of 

this plan and to recommend revisions to the Pacific Flyway Study Committee and the CFWMGBTC. The 

CFWMGBTC and the Pacific Flyway Study Committee will submit all proposed revisions to this management plan 

to both the Central and Pacific Flyway Councils for approval. As appropriate, the Subcommittees will also report on 

accomplishments and shortcomings of its cooperative management efforts to both councils, those state and federal 

agencies having management responsibilities, and those agencies and organizations either interested or cooperating 

in the management of cranes. 
69 

VIII. REFERENCES CITED

Armbruster, M.J. 1987. Habitat suitability index models: greater sandhill crane. U.S. Fish and Wildlife 

Service Biological Report 82(10.140). 26pp. 

Ballard, B.M., J.E. Thompson, M.T. Merendino, J.D. Ray, J.A. Roberson, T.C. Tacha. 1997. Demographics 

of the Gulf Coast subpopulation of Mid-continent sandhill cranes. Paper presented at the 4th Ann. 

Conf. of The Wildlife Society. Snowmass Village, CO, Sept 21-27, 1997 

Benning, D.S., R.C. Drewien, D.H. Johnson, W.M. Brown, and E.L. Boeker. 1997. Spring population 

estimates of Rocky Mountain greater sandhill cranes in Colorado. Proceedings North American 

Crane Workshop 7:165-172. 

Bieniasz, K.A. 1978. Biology of the greater sandhill crane in Routt County, Colorado. M.A. Thesis, 

Univ. Northern Colorado, Greeley, CO. 72pp. 

Bieniasz, K.A. 1979. The greater sandhill crane in Routt County, Colorado, pp. 197-203 in J.C. Lewis, 

editor. Proceedings 1978 Crane Workshop. Colorado State University Printing Service, Ft. 

Collins, CO. 

Boise, C.M. 1976. Breeding biology of the lesser sandhill crane Grus canadensis canadensis (L.) on the 

Yukon-Kuskokwim Delta, Alaska. M.S. thesis. Univ. Alaska, Fairbanks, AK. 79pp. 

Braun, C.E., R.C. Drewien, C.D. Littlefield, and L.H. Walkinshaw. 1975. Conservation committee on status 

of sandhill cranes. Wilson Bulletin. 87(2):297-302. 

Brown, W.M., and R.C. Drewien. 1995. Evaluation of two powerline markers to reduce crane and 

waterfowl collision mortality. Wildlife Society Bulletin. 23:217-227. 

Brown, W.M., R.C. Drewien, and E.G. Bizeau. 1987. Mortality of cranes and waterfowl from powerline 

collisions in the San Luis Valley, Colorado. Pages 128-136 in J.C. Lewis and J.W. Ziewitz, eds. 

Proceedings 1985 Crane Workshop. The Platte River Whooping Crane Trust and U.S. Fish Wildl. 

Serv., Grand Is., NE. 
70 

Buller, R.J. 1982. Distribution of sandhill cranes wintering in Mexico. Pages 266-272 in J.C. Lewis, ed. 

Proc. 1981 crane workshop. National Audubon Society, Tavernier, FL. 

Drewien, R.C. 1973. Ecology of Rocky Mountain greater sandhill cranes. Ph.D. Thesis. Univ. of Idaho, 

Moscow. 152 pp. 

Drewien, R.C. 2005. October 2005 Recruitment survey of the Rocky Mountain population of greater sandhill 

cranes. Special Report in the files of the Central Flyway Representative. Denver, CO. 2pp. 

Drewien, R.C., and E.G. Bizeau. 1974. Status and distribution of greater sandhill cranes in the Rocky Mountains. 

Journal of Wildlife Management. 38:720-742. 

Drewien, R.C., and E.G. Bizeau. 1978. Cross-fostering whooping cranes to sandhill crane foster parents. 

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72 

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73 

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74 

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75 

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76 

IX. ACRONYMS USED

AGFD Arizona Game and Fish Department 

BoR Bureau of Reclamation 

Bosque Bosque del Apache National Wildlife Refuge, New Mexico 

CDOW Colorado Division of Wildlife 

CFWMGBTC Central Flyway Webless Migratory Game Bird Technical Committee 

FWS U.S. Fish and Wildlife Service, Department of the Interior 

IDFG Idaho Department of Fish and Game 

MCP Mid-continent population 

MFWP Montana Fish, Wildlife, and Parks 

MRGV Middle Rio Grande Valley, New Mexico 

MRGV Plan A Plan for the Management for Waterfowl, Sandhill Cranes and other 

 Migratory Birds 

NMDGF New Mexico Department of Game and Fish 

NWR National Wildlife Refuge 

NRCS Natural Resources Conservation Service 

RMP Rocky Mountain Population of greater sandhill cranes 

SEMARNAT Secretaria de Medio Ambiente y Recursos Naturales 

SLV San Luis Valley, Colorado 

TNC The Nature Conservancy 

UDWR Utah Division of Wildlife Resources 

Wildlife Services U.S. Dept. of Agricultural-Animal Plant Health Inspection Services 

WGFD Wyoming Game and Fish Department 

WMA Waterfowl Management Area 

USDA U.S. Dept. of Agriculture 
77 

APPENDIX A.

RMP SANDHILL CRANE POPULATION ESTIMATES, RECRUITMENT, AND HARVEST SUMMARIES, 1981-2005. * 

SURVEY 

 

ARIZONA 

Year March Total San 

Luis Valley 

September Total 

Pre-migration 

% 

Juvenile 

Fall, San 

Luis 

Valley 

Recruitment 

Rate 

5-Year Mean 

Total Allowable 

Harvest 

Harvest 

Allocation 

Actual 

Harvest 

1981 NC 7.6 20 

1982 NC 8.8 9 

1983 NC 11.6 35 

1984 13,125 8.1 33 

1985 20,429 9.0 9.0 40 

1986 15,382 5.8 8.6 23 

1987 15,121 17,481 5.4 8.0 60 

1988 19,135 3.4 6.3 166 40 

1989 17,303 4.1 5.5 800 96 51 

1990 20,868 6.5 5.0 374 39 9 

1991 16,519 5.3 4.9 800 85 44 

1992 

20,014 

(ground count) 19,297 5.2 4.86 800 82 39 

1993 

17,597 (poor 

conditions) 6.1 5.4 780 76 61 

1994 15,063 3.9 5.36 864 84 27 

1995 11,939-18,557 16,028 6.4 5.34 547 65 33 

1996 10,341-18,458 16,938 9.4 6.20 545 65 27 

 October Total 

San Luis Valley 

September Total 

Pre-migration 

 

3-Year Mean 

1997 13,620-24,056 18,036 9.7 8.5 632 56 22 

1998 18,202 11.2 10.1 693 50 37 

1999 19,501 8.4 9.9 974 64 21 

2000 19,990 6.7 8.8 1,141 75 37 

2001 

 

16,559 5.8 7.0 1,175 77 26 

2002 

 

18,803 5.2 5.9 833 55 42 

2003 

 

19,523 7.1 6.0 668 44 34 

2004 18,510 9.4 7.2 656 43 35 

2005 

 

20,865 10.8 9.1 906 59 50 
78 

APPENDIX A. (continued)

* Appendix A includes the historic data used to calculate allowable harvest, as it was recorded in this plan. Appendix B is a rework of 

the SLV spring survey data by Benning et al. (1997). The discrepancies in spring survey data resulted from their application of 

correction methods. 

 Ranges are minimum and maximum estimates of RMP greaters based on the numbers of cranes in the overlap range for RMP 

greaters and mid-size cranes. 

 

WYOMING UTAH NEW MEXICO 

Year 

Harvest 

Allocation 

Actual 

Harvest 

Harvest 

Allocation 

Actual 

Harvest 

Harvest 

Allocation 

Middle Rio 

Grande Southwest 

1981 

1982 143 

1983 154 

1984 101 

1985 138 

1986 195 

1987 190 

1988 212 128 793 190 120 

1989 128 125 68 54 454 483 0 

1990 70 58 49 35 184 79 0 

1991 150 101 70 48 450 34 13 

1992 154 168 80 0 388 126 21 

1993 120 115 70 28 415 277 20 

1994 152 150 73 34 401 406 10 

1995 100 77 46 27 268 ≅ 198 12 

1996 100 84 50 32 252 236 4 

* Middle Rio Grande Valley (MRGV), Southwest New Mexico (SW), Estancia Valley (EV) 

 *MRGV *SW *EV 

1997 100 82 45 30 198 111 3 

N/A 

1998 110 93 35 34 242 173 7 

N/A

1999 140 124 69 54 305 189 9 

N/A

2000 170 163 80 69 358 248 6 3 

2001 170 142 83 77 386 290 9 0 

2002 132 132 66 60 261 154 13 0 

2003 106 72 53 57 210 169 3 0 

2004 104 124 52 53 206 172 15 2 

2005 144 116 74 62 284 225 10 1 
79 

APPENDIX A. (continued)

 

MONTANA COLORADO IDAHO 

Year 

Harvest 

Allocation 

Actual 

Harvest 

Harvest 

Allocation 

Actual 

Harvest 

Harvest 

Allocation 

Actual 

Harvest 

TOTAL 

HARVEST 

(excluding 

Mexico) 

1981 20 

1982 152 

1983 189 

1984 134 

1985 178 

1986 218 

1987 250 

1988 478 

1989 760 

1990 181 

1991 240 

1992 59 42 

 

382 

1993 

 

45 

 

704 

1994 69 40 667 

1995 44 41 0 0 0 0 388 

1996 54 49 0 0 20 20 417 

1997 66 62 0 0 148 136 446 

1998 65 59 0 0 170 135 538 

1999 78 71 40 40 248 190 698 

2000 110 91 40 20 273 193 830 

2001 110 87 40 0 273 278 898 

2002 81 51 0 0 213 194 643 

2003 64 50 0 0 171 146 528 

2004 63 51 0 0 168 142 594 

2005 88 49 0 0 231 189 702 
80 

APPENDIX B

SUMMARY OF EXPERIMENTAL SPRING SURVEYS CONDUCTED FROM 1984-96 IN THE SAN 

LUIS VALLEY, COLORADO * 

 

Year/Date 

Raw 

Aerial 

Estimate 

Adjusted 

for 

Estimation 

Bias 

(EstimateSE) 

Crew 

Estimation 

Error 

Proportion 

of Lessers 

Adjusted to 

Remove 

Lessers a

(EstimateSE) 

RMP Cranes 

Outside 

Survey Area 

Aerial 

Survey 

Conditions 

 

Population 

Index 

1984/ 14-15 10,962 14,488 + 

918 

-24.3 % 

n=42 b

 6.4 % c

 13,562 + 

859 

 550 

 (NM-500) 

 (CO-50) 

 

Poor 

 

 14,112 

1985/ 13-14 18,393 21,773 +

1,403 

-15.5 % 

n=75 

 6.4 % c 20,382 +

1,314 

 0 Good 20,382 

1986/ 8-9 14,031 

 d d

 n= 8 

 6.4 % c

 13,135 + 

17 

 20 (WY) Poor 13,155 

1987/ 14 13,561 15,661 + 

778 

-13.4 % 

n=21 

6.4 % 

n=5,056 

14,660 + 

729 

 0 Poor 14,660 

1988/ 3-4 17,510 

 d d

 n= 2 

6.5 % 

n=7,617 

16,381 + 

21 

 22 (UT) Poor 16,403 

1989/ 11 17,302 18,389 + 

963 

- 5.9 % 

n=50 

7.5 % 

n=6,795 

17,004 + 

891 

 0 Good 17,004 

1990/ 14 20,851 24,593 +

1,341 

-15.2 % 

n=83 

13.7 % 

n=8,298 

21,221 +

1,157 

 275 (CO) Good 21,496 

1991 9 19,990 18,405 + 

685 

+ 8.6 % 

n=69 

12.8 % 

n=9,406 

16,045 + 

598 

 175 (CO) Good 16,220 

1992/ 14 23,516 e 

 d

 

 d n= 0 

15.0 % 

n=5,998 

19,999 + 

28 

 9 (CO) Poor e 20,008 

1993/ 11 17,576 

 d d n=0 

 6.3 % 

n=5,698 

16,478 + 

18 

 1,260 

 (CO-70) 

(NM-1,190) 

Poor 17,738 

1994/ 6 17,229 16,035 + 

884 

+ 7.4 % 

n=33 

 6.1 % 

n=7,353 

15,063 + 

831 

 203 

 (NM-137) 

 (CO-66) 

Fair 15,266 

1995/ 7 25,276 23,390 +

1,215 

+ 8.1 % 

n=70 

12.6 % 

n=7,448 

20,229 +

1,052 

 0 Good 20,229 

1996/ 11 23,019 26,379 +

1,780 

-14.5 % 

n=47 

13.8 % 

n=9,561 

22,737 +

1,535 

1,010 (CO) Good 23,747 

x (13 yr) 10 18,401 19,902 +

1,107 

- 7.5 % 

n=38 

10.1% f

n=7,323 

17,454 + 

696 

 271 All Years 17,725 

x (7 yr) g 11 21,192 22,155 +

1,231 

- 6.1 % 

n=66 

11.7 % 

n=7918, 

19,660 + 

939 

 243 Good 

Years 

19,869 

a

 Calculated after removing estimation bias. 

b

 Number of flocks in photographic sample. 

c

 Adjusted with 1987 value as no surveys to determine proportion of lessers were conducted in 1984-86 

d

 No adjustment made (sample too small). 

e

 Ground counts on feeding sites (n=13). 

f

 Years 1984 - 86 not included. 

g

 Includes 7 years considered comparable (1985, 1989, 1990, 1991, 1992, 1995, and 1996). 

* Source: Benning, D.S., R.C. Drewien, D.H. Johnson, W.M. Brown, and E.L. Boeker. 1997. Spring population estimates of Rocky Mountain 

greater sandhill cranes in Colorado. Proc. North Am. Crane Workshop. 7:165-172. 
81 

APPENDIX C.

WHOOPING CRANE EXPERIMENTS IN THE ROCKY MOUNTAIN REGION 

In 1975, RMP sandhill cranes known to winter in the MRGV were used experimentally as foster-parents 

in an attempt to establish a second free flying, migratory population of whooping cranes (Drewien and 

Bizeau 1978). From 1975-88, 288 eggs were transferred to sandhill crane nests, 210 hatched and 87 

fledged. The RMP whooping crane population peaked at 35 in 1984-85. Additional efforts to introduce 

captive female whooping cranes or chicks into male territories were unsuccessful. Failure to produce any 

chicks or mated pairs and high mortality resulted in discontinuing the program in 1994 (USFWS 1994). 

In 1997, an experiment was conducted to evaluate the feasibility of imparting learned migration behavior to 

captive-reared whooping cranes by imprinting them on, and leading them with, an ultra-light aircraft and its 

pilot. This technique was later applied to reintroduction efforts within the central and eastern U.S. 

Antecedent to this research, a similar project was done in 1995-96 using surrogate sandhill cranes. Eleven 

sandhills were captive reared in 1995 at a location in southeast Idaho and led 800 miles to Bosque del 

Apache NWR in central New Mexico. Four survived and migrated north in spring. Three of the 4 returned 

to Bosque del Apache NWR in fall, 1996. The research was repeated using 8 sandhills in 1996 to refine the 

technique. 

The whooping crane experiment began in summer, 1997, with 7 captive chicks (USFWS 1997). FWS 

published a final rule in the Federal Register on 21 July, 1997, designating the Rocky Mountain population 

of whooping cranes experimental/nonessential. The research proposal was to lead the cranes with an ultralight aircraft following a migration route from southeast Idaho to Bosque del Apache in late summer/early 

fall, then to see if the birds migrate north independently in the spring. Four whooping cranes and 8 

sandhills were part of the experiment following an ultralight aircraft to Bosque del Apache NWR. Two 

whooping cranes were lost to predators at Bosque NWR and two migrated north in the spring. 

The last RMP whooping crane was seen the winter of 2001-02 in the Casa Colorada WMA, NM area. 

There are no plans to introduce additional whooping cranes into the Rocky Mountain region (U.S. 

Department of Interior, USFWS 2001). 

The presence of whooping cranes required adjustments to the MRGV sandhill crane and light goose 

hunting programs and required hunters pass a bird identification course to participate. These education 

programs were successful, as no RMP whooping cranes were lost to hunting. 
82 

APPENDIX D.

RATIONALE FOR REVISING THE HARVEST ADJUSTMENT FACTOR “f” IN THE FORMULA TO 

CALCULATE ALLOWABLE ANNUAL HARVEST 

The subcommittee discussed whether the population goals and thresholds formerly established for the spring survey 

would be appropriate for fall surveys. The committee recognized fall surveys would not provide complete counts 

because cranes are more dispersed and some ingress and egress can occur during the count. Therefore, fall surveys 

are considered a minimum estimate and more appropriately treated as an index. Accordingly, the committee felt 

revisions of the population goals, thresholds, and harvest criteria were warranted. The population objective range 

was changed from 18,000-22,000 to a fall survey index of 17,000-21,000. The minimum threshold for approving a 

hunting season was changed from 16,000 to 15,000. The harvest adjustment factor in the original allocation 

formula was initially revised as follows: 

 f = a variable factor used to adjust the total harvest to achieve a desired effect on the entire 

 population (C) when: 

 Original Harvest Adjustments Revised Harvest Adjustments

 C < 16,000 -- f = 0.0 C < 15,000 -- f = 0.0 

 C = 16,000-18,000 -- f = 1.5 C = 15,000-16,000 -- f = 1.0 

 C = 18,000-22,000 -- f = 2.0 C = 16,000-18,000 -- f = 1.5 

 C = 22,000-24,000 -- f = 2.4 C = 18,000-20,000 -- f = 2.0 

 C > 24,000 -- f = 3.0 C > 20,000 -- f = 2.4 

This modification would have enabled some harvest at populations under 16,000, maintained 

the same allocation at 16,001 to 18,000, provided a 5 % more restrictive allocation between 

18,001 and 20,000 (C = 19,000 instead of 20,000), and provided at least 20 % more liberal 

allocation above 20,000 (f = 2.4 instead of 2.0 and C = actual population instead of 20,000). 

The original harvest adjustment factor and the above revision are step functions. The step function approach 

produces relatively stable regulations within discrete population ranges. However, drastic changes in allowable 

harvest happen at the break-off points. In addition, higher harvest rates are prescribed at the lower end of a 

population interval, and lower harvest rates at the upper end of the same interval. This is counterintuitive. On the 

other hand, a continuous, exponential harvest rate avoids the instability caused by sharp changes in harvest over 

very short population increments. The first approximation of a continuous “f” was developed by fitting a curve to 

the mid-points of the revised step intervals defined above. The continuous “f” function increased exponentially, 

reflecting the need for higher exploitation rates at higher population levels. The function was: 

 f = [C/15,000]3

 

This function would have enabled the allowable harvest rate to gradually increase from 2.5 % at C=15,000 to 5.9 % 

at C=20,000. Based on 5-year average population parameters ending in 1996, this harvest function would have 

produced a population equilibrium around 17,400. 

Recognizing the uncertainties involved with the new fall surveys and harvest formula, the subcommittee decided to 

define an “f” function which prescribed slightly more conservative harvest rates. A 2nd alternate formula (the one 

ultimately adopted) was developed using 16,000 instead of 15,000 in the denominator of the “f” function (Fig 1). 

Table A. is a summary of potential harvest allocations comparing the original formula with the second (adopted) 

revision based on the following harvest factor: 

 

f = [C/16,000]3
83 

Table A. Comparison of allowable harvests based on the original crane plan formula and the 

revised formula using a continuous, exponential “f” (harvest factor) function. a

 

___________________________________________________________________________________ 

 

 Original Revised Formula with 

 Crane Plan f = Fn(C) = (C/16,000)3

 Formula and C = Actual Count 

C = 

Population Fall H H 

Estimate Pop Allowable Harvest Allowable Harvest 

or Index b Estimate c

 f Harvest Rate f Harvest Rate

15,000 (15,991) 0.00 000 0.00 % 0.82 307 2.01 % 

16,000 (17,058) 1.50 632 3.71 % 1.00 397 2.42 % 

17,000 (18,124) 1.50 632 3.49 % 1.20 506 2.89 % 

18,000 (19,190) 2.00 992 5.17 % 1.42 636 3.41 % 

19,000 (20,256) 2.00 992 4.90 % 1.67 789 3.99 % 

20,000 (21,322) 2.00 992 4.65 % 1.95 969 4.62 % 

21,000 (22,388) 2.00 992 4.43 % 2.26 1,178 5.31 % 

22,000 (23,454) 2.40 1,309 5.58 % 2.60 1,419 6.06 % 

23,000 (24,520) 2.40 1,369 5.58 % 2.97 1,694 6.86 % 

24,000 (25,586) 3.00 1,786 6.98 % 3.38 2,009 7.72 % 

25,000 (26,652) 3.00 1,860 6.98 % 3.81 2,365 8.64 % 

26,000 (27,719) 3.00 1,934 6.98 % 4.29 2,767 9.62 % 

___________________________________________________________________________________ 

a

 All calculations assume the 1996 5-year recruitment average @ 0.0620. 

b

 Spring or fall count used in formula. 

c

 Fall recruitment added to the spring count only. 

 
84 

APPENDIX E.

SUMMARY OF MAJOR JULY 2006 REVISIONS 

Revision Page

Update Central Flyway technical committee name................................................. ii 

References to the Gulf Coast subpopulation were changed to the Texas Coastal 

subpopulation to match literature citations.......................................................... 1 

Include Alberta as confirmed RMP greater sandhill crane breeding range...................... 1 

Include RMP greater sandhill crane natural history................................................ 2-10 

Remove section pertaining to the whooping crane experiment and included as Appendix C.. 2 

Update distribution map................................................................................ 11 

Terminate the San Luis Valley fall population survey and direct efforts to the fall premigration 

survey to estimate the population and determine annual harvest allocation...................... 12 

Define fall premigration survey reliability.......................................................... 12 

Objectives B and C were combined into Objective B.............................................. 13 

Objective C included wildlife watching and other nonconsumptive uses in recreational uses.. 13 

Minimizing crane crop depredations was included as Objective D............................... 14 

Update population counts, locations and problems in the Distribution section................. 15-25 

September premigration estimates in Table 1 were updated and includes current survey 

sites....................................................................................................... 20 

Include map of September premigration survey sites as Figure 2................................. 23 
85 

Update peak MRGV winter counts in Table 2...................................................... 26 

Update Number and Population Counts section..................................................... 27-29 

Insert San Luis Valley annual recruitment estimates as Table 3.................................. 29 

 

Update Habitat section................................................................................. 29-31 

Update state sections under Management and Research.......................................... 31-42 

Update responsible Mexico agency.................................................................. 36 

Update state sections under Problems................................................................ 43-47 

 

Update state sections under Habitat.................................................................. 47-54 

Update Use of Cranes section........................................................................ 54-61 

Changed requirement that states annually monitor racial composition in operational hunt areas 

to once every 3 years..................................................................................... 56 

Remove requirement that states monitor racial composition if 100% of the harvest is 

considered RMP greaters................................................................................ 56 

Eliminated the floating allocation with half going to summer states and half to winter/migration 

states...................................................................................................... 58 

Revised formula for allocating unused state allocations............................................ 57-58 

Review state allocations every 5 years using the recent 5-year pre-migration surveys to 

determine summer state locations....................................................................... 58 

Revised data that must be reported to the Subcommittees......................................... 59 

Standardized definition for crippling loss............................................................ 59 
86 

Eliminate 30-day season and 9-crane season limit.................................................. 59 

Delete reference to whooping crane contingency plan requirements.............................. 60 

Update Crop Damage Control section................................................................ 62-63 

Deleted spring and October surveys in the San Luis Valley and midwinter surveys to monitor 

population................................................................................................ 64 

Updated fall pre-migration survey sites............................................................... 66 

Updated Research section............................................................................... 67-68 

Deleted the whooping crane/ultra-light experiment under Research section and included 

under Appendix C.............................................................................................. 68 

Removed Pacific Flyway subcommittee chairman rotation........................................ 68 

Updated Appendix A. RMP sandhill crane population estimates, recruitment, and harvest 

summaries................................................................................................ 77