Adult birds have red, black and grey feathers marking their head, which are in high contrast to the white on their body. Immature whooping cranes are whitish and mottled with brownish feathers. Their legs, wingtips and bills are black. Since , the Canadian Wildlife Service and the U. Fish and Wildlife Service began captive breeding and reintroduction programs, and as of there are four wild populations totalling cranes, including three reintroduced populations in the eastern U.
During their summer breeding season, whooping cranes inhabit areas with poorly drained soil, with wetlands or shallow ponds separated by narrow ridges where trees such as white and black spruce and tamarack grow.
Large nests are usually built in shallow water. The male and female build the nest by making a pile of vegetation and then compacting it.
In their Texan wintering ground, the birds can be found in tidal flats, shallow bays and estuarine marshes along the coast. Whooping cranes are an omnivorous bird species, eating a variety of animals and plants. On their breeding grounds in Canada they primarily eat snails, crustaceans, aquatic insects, minnows, frogs and snakes.
During migration, birds sometimes feed on waste grains from fields, such as barley, wheat and corn. First, radio-tracked bird use of Nebraska was more frequent in spring than in fall Table 2 in Howe , p. Disproportionate sampling, coupled with a small sample size, would increase bias against observing stopovers on the central Platte.
Second, Austin and Richert describe a weak tendency for family groups stopping over in Nebraska to be found more frequently at locations away from the Platte River.
Of the 12 migratory passes tracked, eight passes were made by family groups Kuyt , so additional bias against observed stopovers on the central Platte was possible. Radio-tracking data have provided much needed insight into habitat use and behavior during migration. These data suggest that cranes move rapidly through stopover areas Kuyt and use a variety of habitats for foraging and resting during stopovers Austin and Richert ; Howe It is apparent that weather events and migration behavior related to weather and climate may determine where a crane might stop during migration as much as the quality of a potential stopover habitat Kuyt Accordingly, it is difficult to assess how important individual stopover areas may be to individual cranes or to the AWP as a whole.
Lingle, University of Nebraska, unpublished material, March 22, used radiotelemetry data from migrating cranes to argue that habitats on the central Platte River are not critical to whooping cranes, inasmuch as birds that stop at the Platte could readily use other habitats if the Platte River were not available and most whooping cranes appeared not to use the central.
Platte River at all. Conclusions of Pitts and Lingle should be taken with caution, however, because they are derived from data on just five whooping cranes that made a total of 12 flights over Nebraska at a time when the size of the AWP was less than half what it is now Figure Furthermore, the probability of any tracked crane stopping at the Platte was biased by the nonrandom grouping of experimental birds by social status a chick with parents vs a nonbreeding bird and by season fall vs spring.
More data on radio-tracked or satellite-tracked birds are clearly needed. Howe , Table 2 , in contrast, describes Nebraska as an important area for whooping cranes in spring. If that is true, assessment of the importance of individual habitat areas must be carried out over sufficient periods to incorporate potential variations in conditions.
The radio-tracking study examined whooping crane habitat use over a relatively short period 4 years and should be expanded temporally to include wider ranges of environmental conditions. Assessment of central Platte River habitats should not be made independently of events in other regions.
Relative importance of a given habitat to the population of a species of concern is typically measured by the degree to which that habitat is preferred by individuals of the population. Habitat suitability indexes therefore depend on habitat use in relation to habitat availability. Assessments of the suitability of specific habitat characteristics for whooping cranes or the degree to which alternative habitats may be available to cranes now using areas of diminished quality begin by addressing issues of scale: within local habitats, within the home range of individuals, within the home range of the population, and within the entire geographic range of the species Johnson Researchers who fail to identify their scale of analysis may miss important relationships.
For whooping cranes, pertinent questions about habitat use in the central Platte River are connected to roosting Johnson ; Austin and Richert , although foraging in nearby wetlands is also important Lingle A number of reports have examined habitat selection for whooping cranes on all four scales. Within habitats, night roosts have a number of physical characteristics believed to be important, including water depth and substrate profile Johnson ; Faanes et al.
Within a. Within the home range of a population, they can select for stopover areas between larger regions, such as the central Table Playas as opposed to the central Platte Richert Finally, within the geographic range of the species, they can select the state of Nebraska as a major location for stopovers in spring but may prefer Kansas and Oklahoma in fall Howe Austin and Richert summarized habitat evaluations at all known migration stopovers in the United States for whooping cranes from to On migration stopovers in Nebraska, whooping cranes typically use riverine habitats to roost at night and feed in upland usually agricultural or wetland habitats during the day.
Those findings represent descriptions of habitat that whooping cranes have actually used but do not represent use of habitats in relation to their availability or to randomly chosen habitats, so interpretation of the data on which they are based is limited.
Foraging sites in wetlands tended to have characteristics similar to those of roost sites described below. Water where whooping cranes foraged was shallower, on the average, than in the wetland as a whole. Physical characteristics within agricultural habitats used by foraging cranes were not evaluated, but these habitats also tended to be open and have short or no vegetation.
Several habitat assessments have focused on roost habitat characteristics. Johnson , p. Roost characteristics for used habitats are different from those for nonused habitats. Faanes et al. Roost locations for whooping cranes were more likely to be surrounded by deeper water than would be expected by chance alone.
Few other studies have examined habitat selection on this geographic scale of selection. Even though substantial data in both quantity and quality are available and reasonable habitat suitability models have been developed, the size of the AWP remains the chief limitation on analysis and interpretation.
Such a small number of birds ensures that some high-quality sites inevitably. For example, Faanes et al. However, the pattern of preference observed might not be the same if the number of whooping cranes using the central Platte were substantially larger. It is difficult to assess how much habitat in the central Platte will be adequate to support a viable delisted population of whooping cranes.
Many reports indicate that the presence of forests is inversely related to the desirability of roosts. Whooping cranes use roosts where the width of unvegetated channel and the nonobstructed view of areas upstream and downstream of the roost are extensive Faanes ; Faanes et al.
Researchers, however, have yet to define specifically what constitutes a nonobstructed view for a whooping crane. Is the presence of a few trees enough to significantly alter use of an otherwise desirable open roost site? More experimentation could be done with habitat modification of forests in the river valley see Chapter 4. Debates about the appropriateness of forests in the Platte River Valley are mired, in part, because only two extremes forest vs open are presented where once an entire gradient of vegetation communities existed.
On a scale expanded to evaluate habitats within a home range, potential additional variables that might distinguish used from nonused habitat for whooping cranes include distance to nearest human development, distance from roost to feeding areas, and variety of habitats used Johnson ; USFWS, unpublished material, June 16, ; Austin and Richert No studies of habitat use by whooping cranes according to availability of those variables have been made; thus, their relative importance has not been quantified.
Foraging whooping cranes use both agricultural and wetland habitats throughout their migration Howe ; Austin and Richert , and this behavior differs from that of sandhill cranes, which strongly prefer agricultural habitats in Nebraska Iverson et al.
Lingle et al. In the specific area of the central Platte, no extensive habitat-use studies have been done for foraging whooping cranes except that several authors characterize whooping crane foraging activities as parallel to sandhill crane preference for foraging in agricultural areas e.
From analysis on the scale of the Platte River Valley, more is known about use of roost habitats by whooping cranes. Within the valley, few whooping. Riverine roost sites are important whooping crane habitats throughout Nebraska Austin and Richert , not just on the central Platte. In Nebraska, and elsewhere in the flyway, wetlands not associated with the river also serve as important roosting habitats for whooping cranes in the AWP Austin and Richert Night roosts used by whooping cranes tend to be isolated from human disturbance and are within 1 mi of foraging sites.
The relative availability of nonriparian habitats is not known. In general, wetlands are important to migrating whooping cranes for both foraging and roosting. In the central Platte, use of riverine habitats by whooping cranes is well documented and appears important to their survival.
Preference studies have not been done on this scale and, although useful, will be limited by the same problem of small population size as noted above. Telemetry studies did not find riverine habitats important to roosting whooping cranes, however, because the few tracked birds primarily used palustrine wetlands Howe Bias occurred in both studies.
Austin and Richert identified the limitations to analysis of habitat-use evaluations for migratory whooping cranes.
Comparisons among sites are difficult because efforts to observe whooping cranes along the entire 4, km migration route are uneven. Some regions are subject to underreporting Howe Still, the high incidence of use of riverine habitat by whooping cranes in Nebraska, compared with other states, is striking. The quality of both palustrine and riverine habitats in Nebraska is high Stahlecker and, accordingly, these wetlands are used extensively by whooping cranes Austin and Richert With the opportunistic and nontraditional patterns of habitat selection exhibited by whooping cranes, it is difficult to predict habitat preferences on the scale of home ranges.
Although nonhabitat variables such as weather events can influence habitat selection greatly Kuyt , the overall pattern of habitat use in Nebraska suggests that the general region of the central Platte including the Rainwater Basin is important to migrating whooping cranes.
On large time scales, as wet and dry periods cycle through the region, the interaction among the sites will probably be important Richert Whooping cranes will need stopover habitat during droughts when wetlands in the Rainwater Basin are dry and during wet years when the Platte River is above flood stage. Maintaining a complex of. Few data relevant to use of habitats by migrating whooping cranes on the largest geographic scale exist. However, telemetry data reported by Howe suggest differences in use of stopover areas between fall and spring migrations.
Whooping cranes appear to spend more time in Nebraska in spring than they do in fall Howe , Table 2, p. In fall, many whooping cranes tend to stop in a Saskatchewan staging area for several weeks before continuing their migration, presumably to acquire fat reserves for migration.
It takes cranes about two daily flights to reach that region in Saskatchewan after leaving their breeding grounds in WBNP Kuyt After leaving Saskatchewan, the birds migrate rapidly and reach Nebraska in days and Texas in days more Kuyt During fall migration from to , several radio-tracked whooping cranes flew over Nebraska without stopping in the state at all Kuyt In spring, however, cranes do not use a staging area Kuyt Longer periods spent in Nebraska in spring may therefore be a function of proximity to ANWR as a starting point.
Collectively examining habitat selection for whooping cranes at all four geographic scales suggests that Nebraska, and the central Platte in particular, provide critical habitat for this species. Climatic variations and development pressures likely over the next 30 years in which whooping cranes will need to recover assuming that current population trends continue will further emphasize the importance of providing stopover habitats for whooping cranes on the central Platte.
Two basic ecological needs of migratory bird species are met by migration stopover or staging habitats: food and a safe resting place. Energy and nutrients are acquired and stored for use during future phases of the annual cycle see Alisauskas and Ankney The reserves can be used to provision future flight, allow birds to persist through periods of food shortage, or help to meet reproductive needs when exogenous food resources are insufficient. Because energy and nutrient reserves are acquired in one stage of the annual cycle and used in another, mortality and natality can be influenced by events that occur in other stages of the annual cycle, producing a cross-seasonal effect Weller and Batt ; Fretwell Birds require safe environs at each habitat they visit.
Protection from natural predators and relative isolation from human activities contribute to the utility of stopover sites. The central Platte River has historically filled both needs for whooping cranes during their migrations. When whooping cranes leave breeding areas at WBNP, they often fly for 2 or more days to reach a staging area in Saskatchewan, where they remain for a few days to a month Kuyt ; weeks is the average period of occupancy in this fall staging area.
Once whooping cranes leave the Saskatchewan staging area, they typically move rapidly to ANWR, stopping for just short periods at individual stopover sites Kuyt Although no direct data exist, the pattern of migration suggests that birds leave their breeding area with varied body conditions such as amount of stored fat , stop in Saskatchewan and feed intensively on grains to build fat reserves, and then continue with migration once sufficient fat is stored.
A similar pattern of fat storage more directly measured occurs in migrating sandhill cranes in fall Krapu and Johnson Presumably, whooping cranes then arrive at ANWR lean, having used substantial amounts of fat reserves during fall migration.
These measures are also indirect and are inferred from similar patterns of migration physiology of sandhill cranes. Sandhill cranes complete long migrations with substantially reduced fat reserves Krapu et al. Chavez-Ramirez used behavioral descriptions and energetic models to conclude that whooping cranes regain fat reserves in winter areas before beginning their spring migration. They migrate back to WBNP relatively quickly, using stopover habitats en route but no staging areas.
According to data from radio-tracked whooping cranes, not all delays at stopover sites were related to weather delays Kuyt , pp. Presumably, energy and nutrient reserves acquired in winter are used to migrate quickly from Texas to Canada.
Once in breeding areas, whooping cranes initiate nesting soon after arrival. Little food is available when whooping cranes arrive at WBNP, because ice and snow cover typically does not disappear until after nests have been initiated.
Stored fat reserves, in addition to their importance for migration, are probably used for egg formation and incubation. Similar patterns occur in waterfowl, in which links between stored reserves and reproduction have been studied better Alisauskas and Ankney As with sandhill cranes, cross-season effects probably are important for whooping cranes. Chavez-Ramirez argued that variations in winter habitat conditions are related to reproductive effort in the following spring and that winter body condition could affect winter survivorship.
If winter habitat conditions influence mortality or reproduction, it may be that migration-habitat conditions affect whooping cranes in a similar way. Stehn has suggested that habitat quality at ANWR may be declining. The amount of fresh water entering ANWR is important ecologically because it influences overall productivity in the estuary, especially for. Declining fresh-water flows have been linked to the declining abundance of blue crabs Stehn Fresh water for the estuarine refuge comes from the Guadalupe River.
Whooping cranes that leave ANWR with insufficient stored fat will either migrate to WBNP, facing the potential for added mortality and reduced productivity Chavez-Ramirez , or increase stopover times on migration to acquire fat reserves.
Responses by individual birds are likely to vary. For example, nonbreeding subadults may be able to stop longer on migration than can breeding adults because they do not need to initiate nests. The potential for cross-seasonal effects means that if deteriorating habitat conditions in ANWR are severe and long-lasting, whooping cranes may not be able to acquire sufficient fat reserves and will have to acquire them in other habitats, such as the central Platte River.
Few data are available for testing the hypothesis that spring migration habitats influence energy reserves, reproduction, or mortality in whooping cranes. Some birds stay longer on spring stopover areas than do others Kuyt ; Howe , and more whooping cranes stop at the Platte River for long periods than did 25 years ago Figure b.
Other species of waterfowl acquire energy and nutrient reserves on spring staging areas before arrival on breeding grounds in the manner suggested for whooping cranes Barzen and Serie Although relevant data are sparse, the hypothesis warrants further investigation. Documented migration patterns may not predict future patterns of movement in that habitat conditions change over time at the numerous stopover and staging areas.
The changes might be related to the crane population, to climatic adjustments, or to changes in altered agricultural practices.
It is possible that spring migration areas could be used in new ways by whooping cranes. This possibility cautions against underestimating the ecological value of stopover habitats to whooping cranes, especially stopover habitats on the central Platte River. Satellite telemetry studies over multiple years would help greatly in testing these ideas as they have done with sandhill cranes Krapu Accurate yearly counts of the birds arriving on the. Although the total mortality is reasonably well known, causes of death are more problematic.
Of adults and subadults that disappeared away from winter areas between April and November mortality on breeding areas is assumed to be low from , the cause of death is known in 13 cases, five of which were due to collisions with power lines Lewis et al.
Because most deaths of adult whooping cranes occur during migration, mortality may be linked to the quality or quantity of stopover habitats.
A significant portion of the whooping crane population stops at the Platte River during migration Figure a,b. If the Platte River were no longer available, whooping cranes would probably shift their use to other habitats in Nebraska.
Would these shifts alter mortality? Migrating whooping cranes use wetlands near the central Platte River in the Rainwater Basin south of the river or in the central Table Playa to the north Richert Those off-stream wetlands apparently serve as good migration habitats for whooping cranes, except in droughts or during waterfowl disease outbreaks to which these wetlands are prone Friend The Platte River ecosystem is not prone to disease outbreaks, because, in contrast with off-stream wetlands, water is flowing rather than stagnant.
The Platte River also does not dry out as frequently as do surrounding wetlands; therefore, the Platte River provides safer conditions than do surrounding wetlands at least in some years Johnson Crowding of waterfowl and cranes and short-term use of unusual habitats may also affect crane mortality.
John French, discussing health, exercises, diet and training of these birds once on the brink of extinction. This week marks a significant milestone in the conservation and recovery of the endangered whooping crane.
On March 11 and 13, the U. Bird migration patterns are changing rapidly worldwide due to climate and land use changes, and in the case of the endangered whooping crane, its age before youth, leading the way. Four whooping crane chicks raised in captivity began their integration into the wild Saturday as part of the continuing effort to increase the wild population of this endangered species. The dedicated U. Geological Survey scientists and caretakers of the ten gangly, adolescent whooping cranes being publicly released today in Louisiana do just this.
Skip to main content. Search Search. Eastern Ecological Science Center. Whooping Crane Restoration. Science Center Objects Overview Related Science Publications Multimedia News Partners At more than five feet tall with brilliant white plumage, black primary feathers, a red cap, and yellow eyes, the highly endangered Whooping Crane Grus americana is one of the most spectacular birds native to North America.
Below are other science projects associated with this project. Filter Total Items: 2. Year Select Year Apply Filter. Date published: March 13, Contacts: Glenn Olsen, Ph. Date published: December 19, Below are publications associated with this project. Filter Total Items: Year Published: Time within reproductive season, but not age or inbreeding coefficient, influences seminal and sperm quality in the whooping crane Grus americana All living whooping cranes Grus americana are descended from 16 or fewer birds that remained alive in the early s, a bottleneck that puts the species at potential risk for inbreeding depression.
Brown, M. View Citation. Year Published: Experience drives innovation of new migration patterns of whooping cranes in response to global change Anthropogenic changes in climate and land use are driving changes in migration patterns of birds worldwide. Teitelbaum, Claire S. Teitelbaum, C. Year Published: Adaptive management for improving species conservation across the captive-wild spectrum Conservation of endangered species increasingly envisages complex strategies that integrate captive and wild management actions.
Canessa, S. Year Published: Female gonadal hormones and reproductive behaviors as key determinants of successful reproductive output of breeding whooping cranes Grus americana Reproductive success of endangered whooping cranes Grus americana maintained ex situ is poor.
Year Published: Visual pigments, oil droplets, lens, and cornea characterization in the whooping crane Grus americana Vision has been investigated in many species of birds, but few studies have considered the visual systems of large birds and the particular implications of large eyes and long-life spans on visual system capabilities.
Porter, Megan L. Year Published: Demography of a reintroduced population: moving toward management models for an endangered species, the whooping crane The reintroduction of threatened and endangered species is now a common method for reestablishing populations. Servanty, Sabrina; Converse, Sarah J. Demography of a reintroduced population: moving toward management models for an endangered species, the whooping crane; ; Article; Journal; Ecological Applications; Servanty, Sabrina; Converse, Sarah Joanne; Bailey, Larissa L.
Year Published: A hierarchical nest survival model integrating incomplete temporally varying covariates Nest success is a critical determinant of the dynamics of avian populations, and nest survival modeling has played a key role in advancing avian ecology and management. Converse, Sarah J. Andrew; Adler, Peter H. A hierarchical nest survival model integrating incomplete temporally varying covariates; ; Article; Journal; Ecology and Evolution; Converse, Sarah J.
Year Published: Social learning of migratory performance Successful bird migration can depend on individual learning, social learning, and innate navigation programs. Year Published: A matter of tradeoffs: reintroduction as a multiple objective decision Decision making in guidance of reintroduction efforts is made challenging by the substantial scientific uncertainty typically involved.
Year Published: Archive eggs: a research and management tool for avian conservation breeding Worldwide, approximately bird species are captive-bred for reintroduction into the wild. Smith, Des H. Year Published: Bayesian analysis of multi-state data with individual covariates for estimating genetic effects on demography Inbreeding depression is frequently a concern of managers interested in restoring endangered species.
Andrew; Urbanek, Richard P. Bayesian analysis of multi-state data with individual covariates for estimating genetic effects on demography; ; Article; Journal; Journal of Ornithology; Converse, Sarah J. Year Published: Evaluating release alternatives for a long-lived bird species under uncertainty about long-term demographic rates The release of animals to reestablish an extirpated population is a decision problem that is often attended by considerable uncertainty about the probability of success.
Moore, Clinton T. Evaluating release alternatives for a long-lived bird species under uncertainty about long-term demographic rates; ; Article; Journal; Journal of Ornithology; Moore, Clinton T. Below are multimedia items associated with this project. Filter Total Items: 7.
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