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COSEWIC Assessment and Update Status Report on the
Whooping Crane
Grus americana
in Canada
ENDANGERED
2000
COSEWIC COMMITTEE ON THE STATUS OF ENDANGERED WILDLIFE IN CANADA
COSEPAC COMITÉ SUR LA SITUATION DES ESPÈCES EN PÉRIL AU CANADA COSEWIC status reports are working documents used in assigning the status of wildlife species
suspected of being at risk. This report may be cited as follows:
Please note: Persons wishing to cite data in the report should refer to the report (and cite the author(s));
persons wishing to cite the COSEWIC status will refer to the assessment (and cite COSEWIC). A
production note will be provided if additional information on the status report history is required.
COSEWIC 2000. COSEWIC assessment and update status report on the Whooping Crane Grus americana
in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 28 pp.
(www.sararegistry.gc.ca/status/status_e.cfm)
Wapple, R.D. 2000. Update COSEWIC status report on the Whooping Crane Grus americana in
Canada, in COSEWIC assessment and update status report on the Whooping Crane Grus americana
in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 1-28 pp.
Previous report:
Gollop, M.A. 1978. COSEWIC status report on the Whooping Crane Grus americana in Canada.
Committee on the Status of Endangered Wildlife in Canada. Ottawa. 23 pp.
For additional copies contact: COSEWIC Secretariat c/o Canadian Wildlife Service Environment Canada Ottawa, ON K1A 0H3 Tel.: (819) 997-4991 / (819) 953-3215 Fax: (819) 994-3684 E-mail: COSEWIC/[email protected] http://www.cosewic.gc.ca Également disponible en français sous le titre Rapport du COSEPAC sur la situation de la Grue blanche (Grus americana) au Canada – Mise à jour. Cover illustration: Whooping Crane — Judie Shore, Richmond Hill, Ontario. Her Majesty the Queen in Right of Canada 2004 Catalogue No. CW69-14/154-2002E-IN ISBN 0-662-32327-0 Recycled paper
COSEWIC
Assessment Summary
Assessment summary – November 2000
Common name
Whooping Crane
Scientific name
Grus americana
Status
Endangered
Reason for designation
This globally endangered species occurs in very small numbers in a very restricted breeding range within
a portion of Wood Buffalo National Park and adjacent area. Human activity and resource development
are potential threats to the population, primarily during migration.
Occurrence
Northwest Territories, Alberta
Status history
Designated Endangered in April 1978. Status re-examined and confirmed in November 2000. Last
assessment based on an update status report.
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COSEWIC
Executive Summary
Whooping Crane
Grus americana
Description
Adult Whooping Cranes have pure white plumage with black primaries with black
and red facial markings. The long legs and large bill are black or grayish-black.
Immature birds have a combination of grayish-white and rusty coloration with no facial
markings.
Distribution
Whooping Cranes formerly bred across much of the central and northern prairies
of North America (a small population also bred in Louisiana) and wintered from New
Jersey to Northern Mexico but vanished from these areas following human settlement
around the beginning of the 20th century. Today the only remaining nesting grounds for
this population lie in an area between the headwaters of the Nyarling, Sass, Klewi and
Little Buffalo Rivers in Wood Buffalo National Park (WBNP). The core breeding area in
WBNP has recently expanded south into the Alberta portion of the park. These birds
migrate 4000+ km from WBNP to winter at and near the Aransas National Wildlife
Refuge (ANWR) along the Texas Gulf Coast.
A second wild flock was established in 1975 in southeastern Idaho from Whooping
Cranes cross-fostered by resident Sandhill Cranes. This flock winters in the middle Rio
Grande Valley of New Mexico. A third non-migratory wild flock was established in 1993
at Kissimmee Prairie, Florida.
Habitat
The nesting grounds in the central portion of WBNP are localized in marshes,
bogs, and shallow lakes that are separated by narrow elevated ridges dominated by an
overstory of black spruce, white spruce, tamarack, and a variety of willows.
Understories consist of dwarf birch, Labrador tea, and bearberry. Nesting areas are
dominated by stands of bulrush, cattail, sedges, musk-grass, and other aquatic plants.
During migration, Whooping Cranes utilize a variety of wetlands and croplands
along their migration corridor for feeding and roosting. Wetlands are more important
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feeding areas for family groups than non-families. Roosting and feeding sites within
one kilometer of each other are preferred.
The wintering habitat at ANWR on the Texas Gulf Coast consists of estuarine
marshes dominated by salt grass, saltwort, smooth cordgrass, glasswort, and sea oxeye, and salt flats dominated by gulf cordgrass. Oak, redbay, and bluestem
characterize upland areas that are managed for cranes and other wildlife.
General Biology
Spring migration commences in late March and is usually complete by the end of
April. The only naturally occurring population of Whooping Cranes breeds in and
around WBNP. Breeding commences at approximately four years of age and occurs
annually thereafter. Nest building commences immediately after arrival and clutch
initiation occurs shortly thereafter. Perennially monogamous pairs lay two eggs per
clutch but rarely fledge more than a single young. The eggs are incubated for
approximately 28 days. Upon hatching, precocial young grow rapidly and begin
sustained flights in mid-August. Young production appears to be associated with
approximately 10-year wet-dry cycles with fewer young produced during dry years. Of
13 breeding pairs studied, mean home range size was 4.1 km2. Departure from the
breeding grounds occurs in mid-September. Fall migration is protracted and often
involves staging for one to five weeks in south-central Saskatchewan. Arrival on ANWR
wintering grounds occurs in late October and mid-November.
Longevity in the wild is estimated to be 22-30 years. Overall mortality for the
WBNP/ANWR population is 9.9% per year. Unguarded eggs and flightless young can
be vulnerable to a variety of terrestrial predators, especially during periods of drought.
Most adult mortality occurs during migration or on the wintering grounds, mainly due to
human-related factors. Non-breeding sub-adults begin fall migration earlier than family
groups. During the period of 1982-84, 68.4% of crane-use days during fall migration
were spent in Saskatchewan. Pairs and family groups establish territories during their
winter tenure at ANWR. During the 1980’s, the average winter territory size was 117 ha
but this has declined recently. Juveniles leave ANWR with their parents in spring and
accompany them on the majority of their northward migration, separating at or near the
breeding grounds. During the period of 1982-84, 43.7% of crane use-days during
spring migration were spent in Saskatchewan.
Whooping Cranes are omnivorous throughout the year. The diet during the
breeding season includes insects, crustaceans, minnows, frogs, snakes, small rodents,
seeds and berries. Staging areas used during migration provide waste grains, as well
as tubers, a variety of insects and small rodents. On the wintering grounds, Blue Crabs
and a variety of clams are the most important food items. Wolfberry and acorns are
consumed in adjacent uplands.
Habitat alteration, hunting, and vulnerability to disturbance on the remaining
breeding grounds were likely major factors in the extirpation of prairie and aspen
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parkland Whooping Crane populations. The current breeding grounds in WBNP are
isolated and relatively undisturbed. On the wintering grounds, Whooping Cranes are
less wary and tolerate human disturbances from barge traffic along the Gulf Intracoastal
Waterway (GIW) and from eco-tourist boats.
Sandhill Cranes likely do not compete with Whooping Cranes for breeding
territories and there is likely little competition with other species for resources in these
areas. On the wintering grounds, however, cranes must share the resources of these
coastal habitats with large numbers of other bird species.
Population Size and Trends
Whooping Cranes were never a common species and their maximum population
probably did not exceed 1,500 individuals. As of 1999-2000, the total population of wild
Whooping Cranes was 260 individuals (187 in the WBNP/ANWR population, two in the
Rocky Mountain population and 87 in the Florida population). Along with the 106
individuals in captivity, the overall population is 382 individuals. The WBNP/ANWR
population has increased by 36.6% over the last ten years (1989-1999) and has an
overall population growth of 3.7% per year.
Limiting Factors and Threats
The breeding range in WBNP is very restricted. Habitat quality, and subsequently,
food resources, is the most important factor regulating Whooping Crane numbers.
Along with perils faced during migration, factors affecting the wintering grounds at
ANWR appear to be more limiting than factors affecting the breeding range at WBNP.
The concentration of Whooping Cranes in the vicinity of ANWR makes them vulnerable
to catastrophic events such as hurricanes or chemical spillage.
Existing Protection
The Canadian and U. S. Whooping Crane Recovery Program calls for the
maintenance of a minimum of 40 breeding pairs in the WBNP/ANWR population and a
minimum of 25 breeding pairs at each of two additional sites. Central Wisconsin has
been recommended as the primary site for the establishment of another migratory flock.
Several sites in Saskatchewan and Manitoba have also been evaluated for future
releases. Whooping Cranes are protected in Canada under the Migratory Bird Treaty,
Migratory Birds Convention Act, National Parks Act, Canada Wildlife Act as well as by
provincial/territorial wildlife acts. This species is also protected in the United States by
the Endangered Species Act.
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COSEWIC MANDATE
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) determines the national status of wild
species, subspecies, varieties, and nationally significant populations that are considered to be at risk in Canada.
Designations are made on all native species for the following taxonomic groups: mammals, birds, reptiles,
amphibians, fish, lepidopterans, molluscs, vascular plants, lichens, and mosses.
COSEWIC MEMBERSHIP
COSEWIC comprises representatives from each provincial and territorial government wildlife agency, four federal
agencies (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal
Biosystematic Partnership), three nonjurisdictional members and the co-chairs of the species specialist groups. The
committee meets to consider status reports on candidate species.
DEFINITIONS
Species
Extinct (X)
Extirpated (XT)
Endangered (E)
Threatened (T)
Special Concern (SC)*
Not at Risk (NAR)**
Data Deficient (DD)***
*
**
*** Any indigenous species, subspecies, variety, or geographically defined population of
wild fauna and flora.
A species that no longer exists.
A species no longer existing in the wild in Canada, but occurring elsewhere.
A species facing imminent extirpation or extinction.
A species likely to become endangered if limiting factors are not reversed.
A species of special concern because of characteristics that make it particularly
sensitive to human activities or natural events.
A species that has been evaluated and found to be not at risk.
A species for which there is insufficient scientific information to support status
designation.
Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.
Formerly described as “Not In Any Category”, or “No Designation Required.”
Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on
which to base a designation) prior to 1994.
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a
recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single,
official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species
and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added
to the list.
Environment
Canada
Environnement
Canada
Canadian Wildlife
Service
Service canadien
de la faune
Canada
The Canadian Wildlife Service, Environment Canada, provides full administrative and financial support to the
COSEWIC Secretariat.
vii
Update
COSEWIC Status Report
on the
Whooping Crane
Grus americana
in Canada
Robert D. Wapple
2000
TABLE OF CONTENTS
SPECIES INFORMATION............................................................................................... 3
Name, Classification and Taxonomy ........................................................................... 3
Description................................................................................................................... 3
DISTRIBUTION ............................................................................................................... 4
North American range.................................................................................................. 4
Canadian range ........................................................................................................... 4
HABITAT ......................................................................................................................... 5
Definition...................................................................................................................... 5
Trends ......................................................................................................................... 8
Protection/Ownership .................................................................................................. 9
GENERAL BIOLOGY .................................................................................................... 10
General...................................................................................................................... 10
Reproduction ............................................................................................................. 10
Survival...................................................................................................................... 10
Physiology ................................................................................................................. 11
Movements ................................................................................................................ 12
Nutrition and Interspecific Interactions....................................................................... 12
Behavior/Adaptability ................................................................................................. 13
POPULATION SIZE AND TRENDS .............................................................................. 15
LIMITING FACTORS AND THREATS .......................................................................... 17
SPECIAL SIGNIFICANCE OF THE SPECIES .............................................................. 18
EVALUATION AND PROPOSED STATUS................................................................... 18
Existing Legal Protection or Other Status .................................................................. 18
Assessment of Status and Author's Recommendation .............................................. 19
TECHNICAL SUMMARY............................................................................................... 20
ACKNOWLEDGEMENTS ............................................................................................. 22
LITERATURE CITED .................................................................................................... 22
THE AUTHOR ............................................................................................................... 25
List of figures
Figure 1. Nesting grounds of Whooping Crane in WBNP............................................... 5
Figure 2. Whooping Crane distribution in North America. .............................................. 6
Figure 3. Whooping Crane migration route through Alberta, Saskatchewan and
Manitoba ......................................................................................................... 7
Figure 4. Composition of WBNP/ANWR Whooping Crane flock in winter .................... 16
List of tables
Table 1. Average linear measurements for wing, culmen and tarsus for adult male
and female Whooping Cranes .......................................................................... 3
List of appendices
Appendix 1. Composition of WBNP/ANWR Whooping Crane flock, 1938-1999 .......... 26
Appendix 2. Composition of the Rocky Mountain Whooping Crane flock, 1975-1998 ..... 27
Appendix 3. Composition of the Florida Whooping Crane flock, 1993-1998 ................ 27
Appendix 4. Population structures of captive Whooping Crane flocks ......................... 28
SPECIES INFORMATION
Name, Classification and Taxonomy
The common name of the Whooping Crane is likely derived from guard call or
unison call vocalizations (Lewis 1995). The Latin name, Grus americana (Linnaeus),
translates as “crane of America” while the French name, Grue blanche d’Amerique,
translates as “white crane of America”. The Whooping Crane is placed in the order
Gruiforme, along with 14 other species worldwide, and belongs to the family Gruidae.
The genus Grus contains nine species that includes both native North America cranes,
the Sandhill Crane and the Whooping Crane. The Whooping Crane has no subspecies.
DNA studies indicate that the Common Crane (Grus grus), a Eurasian species, is its
nearest relative (Love and Deninger 1992).
Description
Adult Whooping Cranes have pure white plumage with black primaries that are
visible only when the wings are outstretched. A red patch covers the crown and black
markings on the forehead extend beneath the eye to form an angular malar stripe.
There is also a dark gray wedge-shaped patch that extends from the back of the crown
over the nape. The long legs and large bill are black or grayish-black. Immature birds
have a combination of grayish-white and rusty coloration with no facial markings. Adult
plumage is acquired during their second year. In flight, cranes fly with legs and neck
fully extended outward. Standing at ≈1.5 m, the male whooping crane is the tallest bird
in North America. Males are slightly larger than females (see Table 1).
Table 1. Average linear measurements for wing, culmen and tarsus for adult male and
female Whooping Cranes (Ridgeway and Friedmann 1941)
Body Part
Male (of 15)
Female (of 7)
Culmen (mm)
Wing (mm)
Tarsus (mm)
601.7
138.5
276.5
597.9
136.7
281.4
Whooping Cranes share their range with several similar looking species. These
include the Snow Goose (Chen caerulescens) and American White Pelican (Pelecanus
erythrorhynchos), both of which have white plumage with black primaries but have short
necks and legs, and very different bill morphology. Egrets and swans also have white
plumage but do not have black primaries. Swans have short black legs that do not
extend noticeably in flight and although egret’s long black legs trail in flight, they fly with
their necks folded on their shoulders.
3
DISTRIBUTION
North American range
The whooping crane once occupied a much wider breeding range that is believed to
have extended in a southeasterly direction from the central and northern prairies of Alberta
and Saskatchewan into southwestern Manitoba, northeastern North and South Dakota,
northwestern Minnesota and Iowa and central Illinois (Allen 1952). In 1939, a small disjunct
population was also found breeding in the marshes north of White Lake, Louisiana.
Today the only remaining nesting grounds for this population lie in Wood Buffalo
National Park (WBNP), which straddles the Northwest Territories border in northeastern
Alberta. Nesting is concentrated in an area lying between the headwaters of the
Nyarling, Sass, Klewi and Little Buffalo Rivers (see Figure 1). Although the park itself is
44,807 km2 and is the largest Canadian national park, the core breeding area, located in
the northeastern corner of the park, is ≈6400 km2 (Brian Johns pers. comm.) The last
documented nesting of a pair of wild Whooping Cranes south of WBNP occurred in
1929 at Luck Lake, Saskatchewan (Hjertaas 1994).
The migratory route extends 4000+ km from the breeding grounds in WBNP to their
wintering grounds in the vicinity of Aransas National Wildlife Refuge (ANWR) along the
Texas Gulf Coast (see Figure 2). The route passes in a southeasterly direction through
northeastern Alberta, south-central Saskatchewan, southwestern Manitoba,
northeastern Montana, western North and South Dakota, central Nebraska and Kansas,
west-central Oklahoma and finally to east-central Texas along the Gulf Coast (Howe
1989, Kuyt 1992). The wintering area for this population is localized in the estuarine
marshes and tidal flats of ANWR and adjacent areas of the central Texas Gulf Coast
(Allen 1952). Spring migration follows the reverse path of the fall trip but it is usually
done in less time, as little as 10-11 days for experienced pairs.
In addition to the WBNP/ANWR flock, a second wild flock was established in 1975
in the Rocky Mountains of southeastern Idaho from Whooping Cranes cross-fostered by
resident Sandhill Cranes. This population winters in the middle Rio Grande Valley of
New Mexico. A third wild flock was established in 1993 at Kissimmee Prairie, Florida.
This non-migratory population descends from captive-reared birds.
Canadian range
The only self-sustaining population of Whooping Cranes breeds in WBNP in
northeastern Alberta and southern Northwest Territories. Their migratory route passes
through northeastern Alberta, south-central Saskatchewan, and southwestern Manitoba
(see Figure 3).
4
Figure 1. Nesting grounds of Whooping Crane in WBNP (Kuyt 1993).
HABITAT
Definition
The nesting grounds of the WBNP/ANWR population are localized in a fragile area
consisting of marshes, bogs, and shallow lakes that vary considerably in size, shape
and depth. Distributed across this poorly drained region of WBNP, these wetlands are
separated by narrow elevated ridges dominated by an overstory of Black spruce (Picea
mariana), white spruce (Picea glauca), tamarack (Larix laricina) and a variety of willows
(Salix spp.). Understories are typically dominated by dwarf birch (Betula glandulosa),
Labrador tea (Ledum groenlandicum) and bearberry (Arctostaphylos uva-ursi). Nesting
areas are dominated by stands of bulrush (Scirpus validus), cattail (Typha spp.), sedges
(Carex spp.), musk-grass (Chara spp.) and other aquatic plants (Allen 1956,
Novakowski 1966, Kuyt 1976b, 1981).
5
WOOD BUFFALO
NATL. PARK
NESTING
WINTER
NESTING
WINTER
WINTER
TROPIC OF CANCER
Former breeding and
wintering areas
Main migration routes
Occurrence beyond
principal range
Figure 2. Whooping Crane distribution in North America (adapted from Allen1952).
6
Figure 3. Whooping Crane migration route. (Meine CD, Archibald G.W. 1996).
The core breeding area in central region of WBNP was approximately 625 km2 in
the mid-1970’s (Gollop 1977), by 1999 it had expanded to include approximately
6400 km2 (Brian Johns pers. comm.). This recent expansion has been to the northwest
and south into the Alberta portion of WBNP (Kuyt 1978, Johns 1998). Despite this
expansion, apparently suitable habitat in other regions of WBNP and in other portions of
the Canadian Sub-Arctic remain unoccupied by Whooping Cranes (Brian Johns, pers.
comm.).
The few remaining birds in the failed Rocky Mountain population summers around
the Grays Lake National Wildlife Refuge, an 8,900 ha high elevation (1,946 m) marsh
7
that borders agricultural fields and other wetlands. The resident Florida population
inhabit a 2,000 km2 area of flat, open saw-palmetto (Serenoa repens) prairie that
contains numerous shallow marshes and lakes. This region is surrounded by a wide
variety of private and publicly owned ranches and wetlands.
During migration, the WPNP/ANWR Whooping Crane population utilizes a variety of
wetlands and croplands along their migration corridor, feeding largely on aquatic organisms
and waste grains. Utilizing different wetland types for roosting during their spring and fall
migration, Whooping Cranes favor temporary and seasonal wetlands in spring, and prefer
semi-permanent and permanent wetlands in fall (Johns et al. 1997). Howe (1989) found
that 70% of feeding sites used by non-family groups were croplands, while 67% of feeding
sites used by families were wetlands. Family groups appear to use more heavily vegetated
wetlands than non-family groups. More densely vegetated wetlands may decrease
predation on young inexperienced birds. Juveniles allocated 25% more time to foraging
than parents, therefore roosting wetlands are likely important feeding sites for young and
may provide a higher protein diet required by juveniles that are not fully grown. Wetlands
constituted 67% of feeding sites for family groups and only 30% for non-families. Although
large wetlands are used by migrating cranes, 41% of roosting wetlands were <0.5 ha, of
which 15% were <0.1 ha. Cranes favoured roosting and feeding sites that were within one
kilometer of each other (Howe 1989, Johns et al. 1997).
The wintering habitat in the vicinity of ANWR on the Texas Gulf Coast consists of
estuarine marshes dominated by salt grass (Distichlis spicata), saltwort (Batis maritima),
smooth cordgrass (Spartina alterniflora), glasswort (Salicornia spp.,) and sea ox-eye
(Borrichia frutescens), and salt flats dominated by gulf cordgrass (Spartina spartinae).
Oak (Quercus virginiana), redbay (Persea borbonia) and bluestem (Andropogon spp.)
characterize upland areas that are managed for cranes and other wildlife (Allen 1952,
Labuda and Butts 1979).
The Rocky Mountain population stages in southern Colorado where they roost in
wetlands and feed in adjacent barley fields (Lewis 1995). These birds winter mainly along
a 50-km portion of the middle Rio Grande Valley in the vicinity of Bosque del Apache
NWR, NM. The Rio Grande and adjacent managed wetlands are used for roosting, while
feeding is concentrated in nearby wetlands and agricultural fields (Lewis 1995).
Trends
Loss of isolated wetland habitat required for breeding is likely a primary reason
why the WBNP/ANWR population of Whooping Cranes does not currently breed south
of WBNP. Repopulation of breeding habitat in these areas is very unlikely because of
high disturbance levels from humans and loss of isolated habitat. Breeding habitat in
WBNP is rather restricted but local pioneering of unclaimed habitat is possible due to
the ample presence of unoccupied suitable habitat within the park and in adjacent
areas. There is a general consensus among experts that the inability for Whooping
Cranes to further expand their breeding grounds may be regulated by conditions on
their wintering grounds at ANWR (USFWS 1994, Lewis 1995, Johns 1998). Since
8
ANWR is situated in an area with heavy boat traffic, much of which is involved in the
transport of petrochemical products, there is potential for this crucial habitat to become
contaminated due to accidental spills. Boat traffic through this area also causes habitat
degradation. Whooping Cranes must also compete with many other bird species that
winter in this region.
Protection/Ownership
The Whooping Crane nesting grounds were protected from competing land use
activities and development in 1922 with the establishment of WBNP, an expansive
(4,288,542 ha) area of Sub-arctic boreal forest and muskeg. This protection was
coincidental and rather fortuitous since the park was established to protect the herds of
wood bison that inhabit the park and another thirty years would pass before it was
discovered that the entire wild population of Whooping Cranes also nested there. This
area is designated as a Zone 1 Special Preservation Area. No access is allowed
between April 15 and October 31, except for park staff and scientists. WBNP was also
designated a World Heritage Site in 1983 by the United Nations Educational, Scientific
and Cultural Organization (UNESCO), which designates it as a place of exceptional
universal value which deserves protection for the benefit of all humanity. The
International Union for the Conservation of Nature (IUCN) designated the Whooping
Crane nesting area in WBNP as a Ramsar site in 1982. Ramsar is an intergovernmental treaty that provides the framework for national action and international co­
operation for the conservation and wise use of wetlands and their resources.
Howe (1989) and Johns et al. (1997) found that most Whooping Crane roost sites
used during migration were on private land, illustrating the importance of co-operation
between private landowners and wildlife managers in protecting feeding and staging
sites for migrating cranes. Some major wetlands along the Whooping Crane’s migration
corridor are also protected, such as Last Mountain Lake National Wildlife Area (also a
Ramsar site) and Luck Lake Heritage Marsh, both of which lie within fall staging areas
in Saskatchewan.
Identification and potential protection for other important Whooping Crane staging
sites in this region via the Important Bird Area (IBA) initiative is currently in progress.
The IBA program in Canada was initiated in 1996, along with parallel programs in the
United States and Mexico. The goal of the program is to identify and protect a
worldwide network of sites necessary to ensure the long-term viability of naturally
occurring bird populations. Sites designated as IBA’s (as of 2001) include WBNP
nesting areas near Fort Smith, NWT and in the Alberta portion of the park, and a
number of sites in Saskatchewan that are known to be used by migrating Whooping
Cranes. These include Eyebrow Lake, Middle Lake, Basin Lake, Blaine Lakes, Last
Mountain Lake (north end), Luck Lake, Midnight Lake, Radisson Lake, Quill Lakes, and
Buffer Lake.
In 1978, the U.S. Fish and Wildlife Service designated critical habitat for
Whooping Cranes at the following nine sites in six U.S. states: Monte Vista NWR, CO;
9
Alamosa NWR, CO; Grays Lake NWR, ID; Cheyenne Bottoms State Waterfowl
Management Area, KA; 88 km along the Platte River, NE; Bosque del Apache NWR,
NM; Salt Plains NWR, OK; and ANWR, TX (USFWS 1994).
GENERAL BIOLOGY
General
The only naturally occurring population of Whooping Cranes breeds in WBNP.
Migration between WBNP breeding grounds and wintering grounds at ANWR extends in
a direct corridor in a southeasterly direction (see Figure 3). Spring migration
commences in late March and is complete by the end of April. It is usually direct and
rapid, taking as little as 10 days for experienced adults (Kuyt 1992). These experienced
birds arrive at the breeding grounds first, often exhibiting site fidelity to nesting territories
held in previous years. Nest building commences immediately after arrival. Clutch
initiation occurs shortly thereafter and is usually complete by mid-May. The eggs are
incubated for 30-35 days (Kuyt 1981). Upon hatching, precocial young grow rapidly and
begin sustained flights in mid-August. Departure from the breeding grounds occurs in
mid-September. Fall migration is often protracted and may take as long as 50 days due
to staging for one to five weeks in south-central Saskatchewan (Kuyt 1992). Arrival on
wintering grounds on the Texas Gulf Coast occurs in late October and mid-November.
Reproduction
Breeding commences at four years of age and may occur annually thereafter.
Some birds fail to nest every year (George Gee, pers. comm.). Perennially
monogamous pairs lay two eggs per clutch but rarely fledge more than a single young.
Both parents share parental duties. Due to the short summer season on the breeding
grounds, only one brood is raised per season. Longevity in the wild is estimated to be
22-30 years (Kuyt and Goossen 1987, Mirande et al. 1993). Whooping Cranes usually
breed in isolated locations, but nests have been recorded as little as 500 m apart in the
highest nesting area densities along the Klewi River and Preble Creek (Brian Johns
pers. comm.). Inexperienced pairs nesting far from running water appear to move their
nest sites closer to running water in successive years (Kuyt 1993). The sex ratio of the
wild population is unknown.
Survival
Overall mortality for the WBNP/ANWR population is 9.9% per year (Brian Johns
pers. comm.). Based on resighting data of marked birds, mortality of wild Whooping
Cranes in their first year of life has been 26.7% and 9.06% during their second year
(Lewis 1995). Female survival to one year of age is half of the rate for males. Survival
rate for both sexes from one year to two years is similar. Older females average slightly
lower survival (78%) than for males (86%). Young production appears to be associated
with approximately 10-year wet-dry cycles with fewer young produced during dry years.
10
Recruitment rate of birds breeding in WBNP has decreased from a mean of 16.1%
during the period of 1938-1966, to 11.5% during 1967-1992. The mean recruitment rate
during this entire period (1938-1992) was 13.9% (Drewien et al. 1995).
There are several major causes of mortality. Unguarded eggs and flightless young
and can be vulnerable to terrestrial predators, especially during periods of drought
which allows easier access to nesting areas. Potential drought-related mortality factors
on the breeding grounds include prolonged food shortages (Kuyt 1976a) and lightningcaused fires (Lewis 1995). Black Bear (Ursus americanus) and Common Raven (Corvus
corax) are known predators of eggs, and Wolf (Canis lupus), Red Fox (Vulpes velox),
and Common Raven are known predators of young cranes (Kuyt et al. 1981, Johns
pers. comm.). Other potential predators on the breeding grounds include Coyote (Canis
latrans), Wolverine (Gulo luscus), and Lynx (Lynx canadensis).
Most adult mortality occurs during migration or on the wintering grounds (Kuyt
1992), mainly because of human-related factors. Collisions with power wires during
periods of low visibility are a major cause of mortality during migration and is a
significant factor affecting long-term recovery of the Whooping Crane (Howe 1989). At
least 21 Whooping Cranes have been killed or seriously injured from such collisions
between 1956-1999 (Lewis 1995, Brian Johns pers. comm.). Although illegal shooting
is less of a problem nowadays, there are four documented cases of birds being illegally
shot at ANWR and a fifth was suspected to have been shot (Lewis et al. 1992), and one
case in Saskatchewan.
Natural predation is also a factor. There is at least one documented case of a
Golden Eagle attacking and killing a Whooping Crane from the Rocky Mountain
population (Windingstad et al. 1981). Another eagle attack was documented in 1997
(Brian Johns pers. comm.). Kuyt (1992) suspected a Golden Eagle of attacking and
injuring an adult crane in Saskatchewan and suggested that perhaps a Great-horned
Owl may have caused the death of a bird at ANWR.
Whooping Cranes are susceptible to a number of diseases, including avian
tuberculosis (Lewis 1995) and avian cholera (Snyder et al. 1987). Coccidia, a parasitic
soil protozoan that can be pathogenic, have been found in droppings collected on crane
wintering grounds (Forrester et al. 1978). Lead poisoning has also been documented
(Snyder et al. 1992) and one adult was known to die of heart disease near its nest in
WBNP (Kuyt 1992).
Physiology
Ellis et al. (1991) describe behavior mechanisms Whooping Cranes use to regulate
body temperature. These include tucking in legs during flight or standing on one leg
during cold weather, adjusting feathers, panting, shivering, and sunbathing. Upon
hatching, the insulative properties of the chick’s plumage appear to allow sufficient
thermoregulation in most conditions (Lewis 1995).
11
The migration of the Whooping Crane, like all other migratory birds, is greatly
affected by weather. Crane departure from ANWR is associated with the eastward
passing of high-pressure systems with accompanying warm southerly winds, high
barometric pressure and excellent visibility. Unfavorable weather, such as strong
crosswinds or precipitation, will limit the progress of migrating cranes until conditions
improve. Increased barometric pressure and associated northerly winds, as well as
good visibility stimulate departure from the breeding grounds (Kuyt 1992).
Movements
Juveniles leave ANWR with their parents and accompany them on the majority of
their northward migration, separating at or near the breeding grounds. During the
period of 1982-84, 43.7% of crane use-days during spring migration were spent in
Saskatchewan (Howe 1989). Juvenile separation from their parents during spring
migration has been documented in Saskatchewan but often does not occur until family
groups reach their nesting grounds in WBNP (Kuyt 1992). Stehn (1984) documented
increased parental aggression towards their young as migration progressed.
Following chick hatching on the breeding grounds, pedestrian movements of family
groups occurs entirely within the breeding territory (Kuyt 1976). After the young are
capable of sustained flight, family groups move about further from the natal territory but
the distance is minimal (Howe 1989). Non-breeding sub-adults leave WBNP earlier
than family groups. The departure of crane groups from the nesting grounds may
stimulate neighboring groups to begin their exodus (Lewis 1995). An 85,000-km2 area
of south-central Saskatchewan provides a fall staging area where Whooping Cranes
may spend from one to five weeks. During the period of 1982-84, 68.4% of crane-use
days during fall migration were spent in Saskatchewan (Howe 1989).
Pairs and family groups establish territories during their winter tenure at ANWR.
During the 1980’s, the average winter territory was 117 ha (Stehn and Johnson 1987).
The average territory size has recently declined due to an increase in the Whooping
Crane population. Sub-adults and unpaired adults form small winter flocks that border
existing territories (Blankinship 1976). The Rocky Mountain population is not territorial
in winter (Lewis 1995).
Nutrition and Interspecific Interactions
Whooping Cranes are omnivorous throughout the year. The diet on the breeding
grounds is poorly documented but is known to include a wide variety of insects and
crustaceans. Berries are consumed in early autumn (Novakowski 1965). Other food
items that are likely important include mollusks, minnows, frogs, snakes, and small
rodents (Allen 1956, Novakowski 1966). Whooping Cranes are also known to stalk
ducklings and a juvenile was observed with a live blackbird in its bill. Observations of
adults feeding on a dead grebe and a flightless young feeding on a dead juvenile
American Bittern suggest carrion may be opportunistically consumed (Cooch et al.
12
1988). Young cranes are fed a diet rich in aquatic invertebrates, most notably dragonfly
nymphs (Bergeson and Bradley in press).
Staging cranes in south-central Saskatchewan feed largely on waste grains
(barley, wheat) as well as tubers, a variety of insects (grasshoppers, crickets), small
rodents (Microtus spp., Peromyscus maniculatus) and snakes (Thamnophis spp.).
Agricultural lands used by migrating cranes between Saskatchewan and ANWR likely
provide a similar diet.
On their Texas wintering grounds, Blankinship (1976) found Blue Crabs
(Callinectes sapidus) and a variety of clams (Tagelus plebius, Ensis minor, Rangia
cuneata, Cyrtopleura costada, Phacoides pectinata, Macoma constrica) to be the most
important food items. Water level is believed to influence which species are most
accessible for capture and consumption. Blue Crabs dominate the diet when tidal flats
are flooded due to heavy rain and during high tides (Nelson et al. 1996). In December
and January tidal flats typically drain due to lower tides. During this time clams are
more predominate in the diet because lower water levels make them more accessible.
Whooping cranes also forage in adjacent uplands to consume wolfberry (Lycium
carolinianum) and acorns (Quercus virginiana), but croplands are rarely visited (Bishop
and Blankinship 1982). Other food items consumed on the wintering grounds include a
variety of shrimp (Callianassa spp., Penaeus spp., Cragnon spp.), crayfish (Cambarus
hedgpethi), snails (Melampus coffeus) and the roots of three-square (Scirpus olneyi)
and cordgrass (Spartina spp.).
Behavior/Adaptability
Whooping Cranes are vulnerable to disturbance on their breeding grounds. This
species’ inability to adapt to increased disturbance in the vicinity of wetlands used for
breeding in the late 1800’s and early 1900’s was likely a major factor in the extirpation
of prairie and aspen parkland populations. The current breeding grounds in WBNP are
isolated and relatively undisturbed.
On the wintering grounds, it is generally felt that Whooping Cranes are less wary
and tolerate human disturbances from barge traffic along the Gulf Intracoastal
Waterway (GIW) and from eco-tourist boats. The heavy barge traffic through this area
is composed largely of petrochemical products. Relatively small chemical spills have
occurred here in the past and there is potential for catastrophic spills in the future
(USFWS 1994). Degradation of wintering habitat from activities associated with the
GIW, such as erosion and waterway maintenance, has caused some habitat losses.
Although hurricanes occur at ANWR, the hurricane season is generally complete by the
time the cranes arrive in November, however, they have devastating potential. A
disastrous hurricane in 1940 caused the deaths of seven of the remaining 13 Whooping
Cranes in the Louisiana flock, which led to the extinction of this population in 1948.
13
The Canadian Wildlife Service and the United States Fish and Wildlife Service
have co-operated in attempts to recover this species. Between 1967 and 1996, 453
Whooping Crane eggs were removed from nests in WBNP for captive rearing, use in
cross-fostering experiments with Sandhill Cranes and in ultralight experiments for
reintroducing flocks. Although both Sandhill and Whooping Cranes lay two eggs per
clutch, it is rare for more than a single young to fledge. Opinions on the effects of egg
removal on Whooping Crane recruitment vary. Mirande et al. (1993) state that the
removal of one of the eggs from the nest does not adversely affect productivity in the
wild breeding population, while Cannon et al. (in press) argue that juvenile recruitment
into the WBNP/ANWR population was significantly greater during years of no egg
collection. The lack of appropriate controls and the number of confounding variables
make these studies difficult to interpret (George Gee pers. comm.).
The Canadian and U. S. recovery program consists of maintaining a minimum of
40 breeding pairs in the WBNP/ANWR population and a minimum of 25 breeding pairs
at each of two additional sites (USFWS 1994, Edwards et al. 1994). The Canadian
Recovery Plan calls for the establishment of one of those additional sites in Canada by
2020 (Edwards et al. 1994). Lyon et al. (1995) evaluated three regions in eastern
Saskatchewan/western Manitoba: Yorkton, Saskatchewan River delta, and Overflowing
River, as potential sites for whooping crane reintroduction. Logistically, the Yorkton
region would be the easiest location for such a reintroduction program; however, it also
has the greatest number of hazards. Sommerfeld and Scarth (1998) evaluated five
marsh complexes in the Interlake Region of Manitoba as potential sites for Whooping
Crane reintroduction. While this area would provide suitable habitat for 25 breeding
pairs, land management and associated disturbance are the most important factors
affecting the success of such as reintroduction in this region. In 1998, the Whooping
Crane Recovery Team (WCRT) made the following recommendations:
1. That a second migratory population be initiated in two phases: Wisconsin to
Florida, and Manitoba to Florida or Louisiana;
2. The feasibility of a reintroduction in Wisconsin should be examined;
3. The first choice for a wintering site is Chassahowitzka, Florida and the second
choice is Marsh Island, Louisiana.
In 1999, the WCRT made the following recommendations:
1. That a second migratory population be reintroduced in the eastern U.S. with
birds summering in Wisconsin and wintering at Chassahowitzka
NWR/St. Martins Marsh Aquatic Preserve, Florida;
2. The first releases should occur in central Wisconsin depending on satisfactory
results from the assessment of contaminant levels that a summering
Whooping Crane population could be exposed to, assessment of aircraft
overflights that could affect a breeding Whooping Crane population,
reintroduction efforts using ultralight aircraft, and a Sandhill Crane trial
migration from central Wisconsin to Florida by ultralight (Brian Johns pers.
comm.).
14
Once the migratory route and amount of dispersal of the new population ensures
that no significant mixing will occur with the WBNP/ANWR population, additional release
sites will be considered. These include other sites in Wisconsin, Seney NWR in
Michigan, the Interlake region of Manitoba, and a wintering population at Marsh Island
Wildlife Refuge in Louisiana (Brian Johns pers. comm.).
There are three captive Whooping Crane flocks managed by the U. S. Fish and
Wildlife Service (USFWS), U. S. Geological Survey, and the Canadian Wildlife Service
(CWS). The first was established in 1966 at Patuxent Wildlife Research Center,
Maryland. A second flock was established at the International Crane Foundation (ICF)
at Baraboo, Wisconsin, and a third flock was established by CWS at the Calgary Zoo in
Calgary. As of 1999, the Patuxent flock had 44 birds, the ICF flock had 31 birds, while
the Calgary Zoo flock had 21 birds (see Appendix 4). Other captive birds include four
adults at the San Antonio Zoological Gardens in Texas and two birds at the Audubon
Institute in Louisiana (Brian Johns pers. comm.).
Whooping Cranes are territorial on both the breeding and wintering grounds. The
male crane usually defends territories. In WBNP, family groups of Whooping Cranes do
not socialize with conspecifics; thus breeding territories are usually well spaced. Kuyt
(1993) found that territory sizes for isolated breeding pairs of cranes varied from
12.0 km2 to 18.9 km2, while pairs using more densely populated regions had territory
sizes that varied from 3.2 km2 to 4.2 km2. Of 13 breeding pairs studied, mean home
range size was 4.1 km2.
Whooping Cranes are known to adapt to varying water levels on the wintering
grounds that affect prey availability (Blankinship 1976). Although they are omnivorous,
the importance of Blue Crab in the winter diet of the Whooping Crane suggests that
factors affecting crab populations may have major consequences for cranes (Johns
1998). No information is available on the effects of drought on the food supply on the
breeding grounds. Low young production during dry years suggests it is likely affected
by wet-dry climatic periodicity.
POPULATION SIZE AND TRENDS
Allen (1952) concluded that Whooping Cranes were never a common species and
that their maximum population probably did not exceed 1,500 individuals. Approximately
90% of the population disappeared between 1870 and 1900 due to the encroachment of
civilization on its breeding grounds south of WBNP. Wintering sites on the east coast of the
United States disappeared around this time due to the greatly increasing human population
and subsequent drainage of marsh habitats (George Gee pers. comm.).
The concentration of Whooping Cranes in the vicinity of ANWR in winter allows
wildlife agencies to very accurately determine population levels and annual trends (see
Figure 4). Breeding grounds censuses are less reliable because of the vastness of
WBNP. The total population of wild Whooping Cranes in the winter of 1999-2000 was
15
276 individuals (187 in the WBNP/ANWR population, two in the Rocky Mountain
population and 87 in the Florida population). Along with the 106 individuals in captivity,
the overall population is 382 individuals (see Appendices 1-4).
200
180
160
No. of wintering birds:
140
120
A d u lt
Young
100
T o ta l
80
60
40
20
1998-99
1995-96
1992-93
1989-90
1986-87
1983-84
1980-81
1977-78
1974-75
1971-72
1968-69
1965-66
1962-63
1959-60
1956-57
1953-54
1950-51
1947-48
1944-45
1941-42
1938-39
0
Year
Figure 4. Composition of WBNP/ANWR Whooping Crane flock in winter (1938-1999).
Since there is no age structure data for the WBNP/ANWR population, it is unknown
exactly how many breeding individuals there are. Kuyt (1981) estimated that 80% of the
adult population of cranes breed in a given year at WBNP, with 60% producing young.
Between 1976 and 1989, 172 of 234 hatchlings (≈73%) reached ANWR on their first trip.
Boyce (1987) demonstrated a 10-year periodicity in Whooping Crane populations. This
may be associated with 10-year wet-dry cycles on the breeding grounds since fewer young
are produced during dry years (Lewis 1995). Although slight decreases in the WBNP/
ANWR population occasionally occur, the WBNP/ANWR population of Whooping Cranes
has been slowly increasing since intensive population monitoring was initiated in 1938 (see
Appendix 1). Beginning in 1977, the core breeding area expanded south into the Alberta
portion of WBNP, representing the first Alberta breeding record in 63 years (Kuyt 1978).
Eight pairs bred in this newly pioneered Alberta region in 1997 (Johns 1998). The
WBNP/ANWR population has increased by 36.6% over the last ten years (1989-1999).
Overall population growth for this population is 3.7% per year (Brian Johns pers. comm.).
16
LIMITING FACTORS AND THREATS
The breeding range in WBNP is very restricted, although apparently suitable habitat in
other areas of the park and in adjacent areas is presently unoccupied by Whooping
Cranes. Lewis (1995) identified habitat quality, and subsequently, food resources, as the
most important factor regulating Whooping Crane numbers. Poor chick production and low
survival appear to be associated with drought conditions on the breeding grounds.
Along with perils faced during migration, factors affecting the wintering grounds at
ANWR appear to be more limiting than factors affecting the breeding range at WBNP.
The concentration of Whooping Cranes in the vicinity of ANWR makes them vulnerable
to catastrophic events such as hurricanes or chemical spillage. One of the major
concerns on these wintering grounds has focussed around the Gulf Intracoastal
Waterway (GIW), which extends from Carrabelle, FL to Brownsville, TX, to protect boats
from wind and high seas. Construction of this waterway in the early 1940’s caused
some loss of wetland habitat. Fifteen per cent of Whooping Crane wintering habitat has
been lost since the early 1940’s due to erosion from boat traffic along the GIW. It is
estimated that 1.6 ha of wintering habitat per year is lost. The Army Corps of Engineers
recently installed concrete slabs along portions of the GIW to reduce erosion (Halpern
1992). This project will be completed during the summer of 2000 (Stehn pers. comm.).
The heavy barge traffic along the GIW is composed largely of petrochemical
products. Relatively small chemical spills have occurred in this region in the past and
there is potential for catastrophic spills in the future. The security of the food base in
this area is also a concern. In 1994, after a winter of low Blue Crab populations, the
number of nesting attempts in WBNP dropped from 43 in 1993 to only 28 (Johns 1998).
Fall staging Whooping Cranes are sometimes found in the company of Sandhill
Cranes during the fall crane hunting season in Saskatchewan. When this occurs, these
sites are closed to hunting until the Whooping Cranes vacate the area. It is also possible
for Whooping Cranes to be mistaken for snow geese during the fall hunting season.
Whooping Cranes do not compete with any other species for breeding territories and
there is likely little competition with other species for resources in these areas. On the
wintering grounds, however, cranes must share the resources of these coastal habitats
with large numbers of pelicans, herons, egrets, waterfowl shorebirds, gulls, and terns.
There is also competition from humans harvesting clams and crabs (Edwards et al. 1994).
There is little human disturbance on the breeding grounds since there is no access
to the breeding area between April and September, except for park staff and scientists.
Subsistence hunting, fishing and trapping still occurs in WBNP by local Aboriginal
groups. These activities are considered an important part of the park’s cultural history
and are not considered to be a threat to nesting Whooping Cranes.
17
SPECIAL SIGNIFICANCE OF THE SPECIES
The only naturally occurring population of whooping cranes breeds in WBNP. It is
a relict population of a once much more widespread species. Concern has been
expressed about the effects of the genetic bottleneck that occurred when the overall
population dipped to 16 birds in 1941. Mirande et al. (1993) found that 87% of gene
diversity was still present in wild Whooping Crane population through 1990 and 95.8%
of diversity existing when the Patuxent captive flock was established still exists.
Glenn (1997) found a greater loss in mtDNA using microsatellites. Only three of
nine haplotypes present in the pre-bottleneck population persists in today’s
WBNP/ANWR population. The least common haplotype before the bottleneck is now
the most common, therefore a genetic shift may have occurred.
A generally cherished and admired species, the whooping crane has been described
as the flagship species of the North American wildlife conservation movement, symbolizing
the critical status that is typical of endangered species worldwide. Whooping Cranes are a
major tourist attraction in staging areas in southern Saskatchewan, and at their wintering
grounds at ANWR. Lewis (1995) reported that an estimated 70,000-80,000 people visit
ANWR each year, mostly in winter. In 1990-91, Whooping Crane tour boats took in
$340,000 (American funds) from approximately 17,000 patrons. Eco-tourism contributes an
estimated $6 million/year (American funds) of gross economic benefits to the local economy
of Rockport, TX. Much of this revenue is derived from the viewing of Whooping Cranes.
EVALUATION AND PROPOSED STATUS
Existing Legal Protection or Other Status
The Migratory Bird Treaty of 1916 between Canada and the United States, and the
Migratory Birds Convention Act in 1917, provided the first government protection for
migratory birds, a category that includes the Whooping Crane. They are also protected
in Canada under the National Parks Act, Canada Wildlife Act as well as by
provincial/territorial wildlife acts. In addition to the Migratory Bird Treaty Act, this
species is also protected in the United States by the Endangered Species Act of 1973.
The Whooping Crane was designated as endangered in 1978 by the Committee on
the Status of Endangered Wildlife in Canada (COSEWIC 1998). An endangered
species is defined as one that is facing imminent danger of extirpation or extinction.
The Nature Conservancy has given this species a G1 ranking, which is defined as very
rare and may be especially vulnerable to extirpation. The Whooping Crane is also
designated as endangered by the Manitoba Department of Natural Resources and
Saskatchewan Environment and Resource Management. The Manitoba Conservation
Data Centre and the Saskatchewan Conservation Data Centre assign the Whooping
Crane an S1 ranking, which is defined as extremely rare and critically imperiled.
18
Assessment of Status and Author's Recommendation
While massive human alterations to the landscape across their pre-1900 breeding
range preclude their re-establishment in these areas, Whooping Cranes should continue
to expand and increase their breeding range within WBNP and possibly into surrounding
regions. Although the attempt to establish a breeding Whooping Crane population in
the Rocky Mountains of Idaho was a failure, other recovery efforts have been
successful thus far. Wild populations of this species are now more numerous than they
have been in nearly a century and although the reintroduced flocks are yet to become
self-sustaining, all three captive flocks are able to maintain themselves and produce
offspring for release in Florida (Brian Johns and Doug Bergeson pers. comm.).
Despite this encouraging news, Whooping Cranes are still vulnerable to imminent
extirpation or extinction. Conditions on the wintering range at ANWR, such as
overcrowding, habitat loss and degradation, disturbance, and competition from other
wildlife species and humans appear to be the most serious threats. Low recruitment,
small clutch size, and delayed sexual maturity limit this species’ ability to rapidly
increase their populations or recover from catastrophic events. Numerous migration
hazards faced during their 4,000-km one-way migration include collisions with manmade obstructions, inclement weather, predation, and illegal hunting. The very
restricted breeding and wintering areas make Whooping Cranes vulnerable to natural
and human-caused catastrophic events. For these reasons, the Whooping Crane
should remain classified as an endangered species.
19
TECHNICAL SUMMARY
Grus americana
Whooping Crane
Grue blanche
Occurrence in Canada: NWT, AB
Extent and Area information
• extent of occurrence (EO)(km²)
•
•
•
specify trend (decline, stable, increasing, unknown)
are there extreme fluctuations in EO (> 1 order of magnitude)?
area of occupancy (AO) (km²)
•
specify trend (decline, stable, increasing, unknown)
•
•
•
are there extreme fluctuations in AO (> 1 order magnitude)?
number of extant locations
specify trend in # locations (decline, stable, increasing,
unknown)
• are there extreme fluctuations in # locations (>1 order of
magnitude)?
• habitat trend: specify declining, stable, increasing or unknown
trend in area, extent or quality of habitat
Population information
• generation time (average age of parents in the population)
(indicate years, months, days, etc.)
• number of mature individuals (capable of reproduction) in the
Canadian population (or, specify a range of plausible values)
•
total population trend: specify declining, stable, increasing or
unknown trend in number of mature individuals
•
if decline, % decline over the last/next 10 years or 3
generations, whichever is greater (or specify if for shorter time
period)
are there extreme fluctuations in number of mature individuals
(> 1 order of magnitude)?
is the total population severely fragmented (most individuals
found within small and relatively isolated (geographically or
otherwise) populations between which there is little exchange,
i.e., < 1 successful migrant / year)?
list each population and the number of mature individuals in
each
•
•
•
•
•
specify trend in number of populations (decline, stable,
increasing, unknown)
are there extreme fluctuations in number of populations
(>1 order of magnitude)?
20
44,807 km² -area of Wood Buffalo
National Park (WBNP)
stable
no
6400 km² core breeding range in Wood
Buffalo National Park
increasing; core breeding range is
expanding into Alberta portion of the
WBNP
no
1
stable
n.a.
stable; breeding habitat abundant in
WBNP & in neighbouring areas in AB.
several years (~10 yrs)
Total # birds: 183 (1988-1999)
Mature birds: 165 (1988-1999)
source: graph on pg 29
Note, effective number < 165
Increasing 36% increase over last 10
years
source: page 29-30
no
Only one breeding population.
Apparently no significant population
subdivision in Canada - thus just one
population with 165 individuals
stable
no
Threats
Species is vulnerable on wintering grounds in Texas – there is overcrowding, competition from other wildlife
species for food, and risk of catastrophic events such as hurricanes and chemical spills. At risk of
catastrophic events also on breeding grounds.
Rescue Effect (immigration from an outside source)
• does species exist elsewhere (in Canada or outside)?
• status of the outside population(s)?
•
•
•
none through natural processes
USA
G1 'Critically Imperilled'
- ABI ranking
Endangered D
- IUCN Red List
Rocky Mountain population in Idaho
4 individuals
Florida population (non migratory)
73 individuals
In captivity
104 individuals
not from natural source
yes, for captive birds
-in WBNP, yes
-resources limited in the wintering
range
none available
is immigration known or possible?
would immigrants be adapted to survive here?
is there sufficient habitat for immigrants here?
Quantitative Analysis
21
ACKNOWLEDGEMENTS
The author wishes to thank Brian Johns (CWS, Saskatoon) and Colleen Hyslop
(COSEWIC) for providing the opportunity to prepare this report. Brian Johns supplied
the required literature and reviewed the manuscript, George Gee and Doug Bergeson
provided editorial comments, Dale Hjertaas (Saskatchewan Environmental Resource
Management) provided assistance with critical Whooping Crane habitats in
Saskatchewan, and Alan Smith (CWS, Saskatoon) provided the Whooping Crane
illustration. Funding provided by the Canadian Wildlife Service, Environment Canada.
LITERATURE CITED
Allen, R.P. 1952. The Whooping Crane. Natl. Audubon Soc. Resour. Rept. 3., New York.
Allen, R.P. 1956. A report on the The Whooping Crane’s northern breeding grounds.
Natl. Audubon Soc. Suppl. Resour. Rept. 3., New York.
Bergeson, D.G. and Bradley, M. In press. Food Items and feeding rates for wild
whooping crane colts in Wood Buffalo National Park. In Proceedings of the 8th
North American Crane Workshop, Albuquerque, NM.
Bishop, M.A. and D.R. Blankinship. 1982. Dynamics of subadult flocks of whooping cranes
at Aransas National Wildlife Refuge, Texas, 1978-1981. Pp. 180-189 in Proc. 1981
intl. crane workship (J.C. Lewis, ed.). National Audubon Society, Tavernier, Fla.
Blankinship, D.R. 1976. Studies of Whooping Cranes on the wintering grounds.
Pp. 197-206 in Proc. Intl. Crane Workshop (J. C. Lewis, ed.). Oklahoma State
Univ. Press, Stillwater.
Boyce, M.S. 1987. Time-series analysis and forecasting of the Aransas-Wood Buggalo
Whooping Crane population. Pp. 1-9 in Proc. 1985 internatl. Crane workshop
(J.C. Lewis and J.W. Ziewitz, eds.). Platte River Whooping Crane Habitat Main.
Trust and U.S. Fish and Wildl. Serv., Grand I., NE.
Cooch, F.G., W. Dolan, J.P. Goossen, G.L. Holroyd, B.W. Johns, E. Kuyt, and
G.H. Townsend. 1988. Canadian Whooping Crane Recovery Plan. Canadian
Wildlife Service.
COSEWIC 1998. Canadian species at tisk, April 1998. Committee on the Status of
Endangered Wildlife in Canada, Ottawa. 21 pp.
Currier, P.J. 1991. Reclamation of crane roosting habitat on the Platte River and
restoration of riverine wetlands. Pp. 403-407 in Proc. 1987 internatl. crane
workshop (J. Harris, ed.). Internatl. Crane Found., Baraboo, WI.
Drewien, R.C., W.M. Brown and W.L. Kendall. 1995. Recruitment in Rocky Mountain
Greater Sandhill Cranes and comparison with other North American crane
populations. J. Wild. Manage. 59: 339-356.
Edwards, R., S. Brechtel, R. Bromley, D. Hjertaas, B. Johns, E. Kuyt, J. Lewis, N. Manners,
R. Stardom and G. Tarry. 1994. National Recovery Plan for the Whooping Crane.
Report No. 6. Ottawa: Recovery of Nationally Endangered Wildlife Committee, 39 pp.
Ellis, D.H., G.W. Archibald, S.R. Swengel, and C.B. Kepler. 1991. Compendium of
crane behavior. Part 1: individual (nonsocial) behavior. Pp. 225-234 in Proc. 1987
internatl. crane workshop (J. Harris, ed.). Internatl. Crane Found., Baraboo, WI.
22
Forrester, D.J., J.W. Carpenter and D.R. Blankinship. 1978. Coccidia of Whooping
Cranes. J. Wildlife Diseases 14: 24-27.
Glenn, T.C. 1997. Genetic Bottlenecks in Long-lived Vertebrates: Mitochondrial and
Microsatellite DNA Variation in American Alligators and Whooping Cranes.
Ph.D. Thesis. University of Maryland at College Park. 303 pp.
Gollop, M.A. 1978. COSEWIC (Committee on the Status of Endangered Wildlife in
Canada) status report on the Whooping Crane Grus americana in Canada. 19 pp.
Halpern, S. 1992. Losing ground. Audubon 94(4): 70-79.
Hjertaas, D.G. 1994. Summer and breeding records of the Whooping Crane in
Saskatchewan. Blue Jay 52(2): 99.
Howe, M.A. 1989. Migration of radio-marked Whooping Cranes from the Aransas-Wood
Buffalo population: patterns of habitat use, behaviour, and survival. Fish Wildl.
Tech. Rept. 21. U.S. Fish Wildl. Serv., Washington, D.C.
Johns, B.W. 1998. Whooping Cranes nesting in Alberta. Blue Jay 56 (1): 31-33.
Johns, B.W., E.J. Woodsworth, and E.A. Driver. 1997. Habitat use by migrant Whooping
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24
THE AUTHOR
Robert Wapple received a Bachelor of Science in biology from the University of
Saskatchewan in 1996. He has had a lifelong interest in nature and environmental
issues and has prepared numerous reports and articles on Saskatchewan fauna.
25
Appendix 1. Composition of WBNP/ANWR Whooping Crane flock, 1938-1999 from winter counts in December each year Year
1938-39
1939-40
1940-41
1941-42
1942-43
1943-44
1944-45
1945-46
1946-47
1947-48
1948-49
1949-50
1950-51
1951-52
1952-53
1953-54
1954-55
1955-56
1956-57
1957-58
1958-59
1959-60
1960-61
1961-62
1962-63
1963-64
1964-65
1965-66
1966-67
1967-68
Adult
14
15
21
14
15
16
15
18
22
25
27
30
26
20
19
21
21
20
22
22
23
31
30
34
32
26
32
36
38
39
Young
4
7
5
2
4
5
3
4
3
6
3
4
5
5
2
3
0
8
2
4
9
2
6
5
0
7
10
8
5
9
Year
1968-69
1969-70
1970-71
1971-72
1972-73
1973-74
1974-75
1975-76
1976-77
1977-78
1978-79
1979-80
1980-81
1981-82
1982-83
1983-84
1984-85
1985-86
1986-87
1987-88
1988-89
1989-90
1990-91
1991-92
1992-93
1993-94
1994-95
1995-96
1996-97
1997-98
1998-99
Subtotal
18
22
26
16
19
21
18
22
25
31
30
34
31
25
21
24
21
28
24
26
32
33
36
39
32
33
42
44
43
48
26
Adult
44
48
51
54
46
47
47
49
57
62
68
70
72
71
67
68
71
81
89
109
119
126
133
124
121
127
125
130
140
152
165
Young
6
8
6
5
5
2
2
8
12
10
7
6
6
2
6
7
15
16
21
25
19
20
13
8
15
16
8
28
19
30
19
Subtotal
50
56
57
59
51
49
49
57
69
72
75
76
78
73
73
75
86
97
110
134
138
146
146
132
136
143
133
158
159
182
183
Appendix 2. Composition of the Rocky Mountain Whooping Crane flock, 1975-1998 Year
1975-76
1976-77
1977-78
1978-79
1979-80
1980-81
1981-82
1982-83
1983-84
1984-85
1985-86
1986-87
1987-88
1988-89
1989-90
1990-91
1991-92
1992-93
1993-94
1994-95
1995-96
1996-97
1997-98
1998-99
Adult
0
3
6
6
8
15
13
10
13
21
27
24
18
14
13
13
12
9
8
4
3
3
3
4
Young
4
3
2
3
7
5
0
4
17
12
4
2
1
0
0
0
0
0
1
0
0
0
3
0
Subtotal
4
6
8
9
15
20
13
17
30
33
31
26
19
14
13
13
12
9
9
4
3
3
6
4
Appendix 3. Composition of the Florida Whooping Crane flock, 1993-1998 Year
1993-94
1994-95
1995-96
1996-97
1997-98
1998-99
Adult
5
9
17
49
58
53
Young
3
6
41
10
7
20
Subtotal
8
15
58
59
65
73
27
Appendix 4. Population structures of captive Whooping Crane flocks at Patuxent Wildlife Research Center (PWRC), International Crane Foundation (ICF), and Calgary
Zoo (beginning in 1993, 20-30 fledged young per year were shipped to Florida) PWRC
Year
1966-67
1967-68
1968-69
1969-70
1970-71
1971-72
1972-73
1973-74
1974-75
1975-76
1976-77
1977-78
1978-79
1979-80
1980-81
1981-82
1982-83
1983-84
1984-85
1985-86
1986-87
1987-88
1988-89
1989-90
1990-91
1991-92
1992-93
1993-94
1994-95
Adult
1
1
5
12
14
14
17
17
17
20
18
19
19
22
22
19
23
27
31
36
35
37
30
32
35
36
37
40
35
Young
0
5
7
5
0
3
0
0
4
0
1
2
3
4
0
7
10
5
7
2
6
9
2
3
5
13
19
16
37
Subtotal
1
6
12
17
14
17
17
17
21
20
19
21
22
26
22
26
35
32
38
38
41
46
32
35
40
49
56
56
72
28
PWRC
Year
1995-96
1996-97
1997-98
1998-99
1999-2000
Adult
39
42
40
44
40
Young
21
18
27
26
1
Subtotal
60
60
67
70
41
ICF
1989-90
1990-91
1991-92
1992-93
1993-94
1994-95
1995-96
1996-97
1997-98
1998-99
1999-2000
14
20
27
25
29
28
28
29
30
30
30
6
11
1
12
6
3
1
4
0
1
1
20
31
28
37
35
31
29
33
30
31
31
Calgary
Zoo
1992-93
1993-94
1994-95
1995-96
1996-97
1997-98
1998-99
1999-2000
4
13
15
18
17
20
20
21
0
3
1
0
0
0
1
0
4
16
16
18
17
20
21
21