Sandhill Crane
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| Sandhill Crane | ||||||||||||||||||||
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 Florida Sandhill Crane,
Grus (canadensis) pratensis. Adult (below) and immature |
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| Grus canadensis (Linnaeus, 1758) |
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and see text |
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Ardea canadensis Linnaeus, 1758 |
The Sandhill Crane (Grus canadensis) is a large crane of North America and extreme northeastern Siberia. It has one of the the longest fossil histories of any extant bird[1]. But although a 10-million-year-old crane fossil from Nebraska is often cited as being of this species[2], this is more likely from a prehistoric relative or the direct ancestor of the Sandhill Crane but may not even belong in the genus Grus, while the oldest unequivocal Sandhill Crane fossil is "just" 2.5 million years old[3]. Still, this is nearly half as old again as the earliest remains of most living species of birds, which are not known from remains older than the Pliocene/Pleistocene boundary some 1.8 million years ago. As these ancient Sandhill Cranes varied as much in size as the present-day birds, even those Pliocene fossils were sometimes described as new species[4]. Grus haydeni on the other hand may or may not have been a prehistoric relative of the living species, or it may actually comprise material of the Sandhill Crane and its ancestor[5].
The common name of this bird references habitat like that at the Platte River, on the edge of Nebraska's Sandhills in the American midwest. This is the most important stopover area for the Lesser Sandhill Crane, Grus (canadensis) canadensis, with up to 450,000 of these birds migrating through annually.
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[edit] Description
Adults are gray overall; during breeding, the plumage is usually much worn and stained, particularly in the migratory populations, and looks nearly ochre. They have a red forehead, white cheeks and a long dark pointed bill. They have long dark legs which trail behind in flight and a long neck that is kept straight in flight. Immature birds have reddish brown upperparts and gray underparts. The sexes look alike. Size varies among the different subspecies. This crane frequently gives a loud trumpeting call that suggests a French-style "r" rolled in the throat.
The only other large grayish-bodied wading bird of North America is the Great Blue Heron. Although this heron is of similar dimensions to the Sandhill Crane and is sometimes mistakenly called a "crane", it is different in plumage details and build, and like other herons it flies with its neck tucked towards the body in a flat "S"-shape.
[edit] Subspecies and evolution
There is considerable variation in size (much of which is clinal) and in migratory habits. A male of G. c. canadensis averages 7.4 lbs (3.34 kg), 39 in (98 cm) in length and has a wingspan of 5.3 ft (1.6 m). A male of G. c. tabida averages 11 lbs (5 kg), 47 in (119 cm) in length and has a wingspan of 7 ft (2.12 m). The southern populations are intermediate, roughly according to Bergmann's Rule.
Three subspecies are resident; pulla of the Gulf Coast of the U.S., pratensis of Florida and Georgia and nesiotes of Cuba[6]. The northern populations exist as fragmented remains in the contiguous U.S. and a large and contiguous population from Canada to Beringia. These migrate to the southwestern United States and Mexico. This crane is a rare vagrant to China, South Korea and Japan and a very rare vagrant to western Europe.
Six subspecies have been recognized in recent times:
- Lesser Sandhill Crane, Grus canadensis canadensis
- Cuban Sandhill Crane, Grus canadensis nesiotes – ESA: Endangered
- Florida Sandhill Crane, Grus canadensis pratensis
- Mississippi Sandhill Crane, Grus canadensis pulla – ESA: Endangered
- Canadian Sandhill Crane, Grus canadensis rowani
- Greater Sandhill Crane, Grus canadensis tabida
The Canadian Sandhill Crane is morphologically not reliably distinct and was never unequivocally accepted as valid subspecies[7]. The other can be somewhat more reliably distinguished in hand by measurements and plumage details, apart from the size differences already mentioned. Unequivocal identification often requires location information, which is often impossible in migrating birds.
George C. Reifel Migratory Bird Sanctuary, Ladner, British Columbia
Analysis of control region mtDNA haplotype data shows 2 major lineages, one including the Lesser Sandhill Crane or Little Brown Crane, the Arctic and the subarctic migratory population. The other lineages can be divided into a migratory and some indistinct clusters which can be matched to the resident subspecies. The Lesser and Greater Sandhill Cranes are quite distinct, their divergence dating roughly to some time during the Late Pliocene or Early Pleistocene, some 2.3–1.2 million years ago (mya). It seems as if glaciation fragmented off a founder population of the Lesser Sandhill Crane, because during each major ice age its present breeding range was frozen year-round. Still, Sandhill Cranes are amply documented from fossil and subfossil remains right to the modern era[8]. Conceivably, they might be considered distinct species already, a monotypic G. canadensis and the Greater Sandhill Crane G. pratensis, which would include the other populations.[6]
It appears as if the scant differences between southern Canadian and western U.S. populations result from genetic drift due to the recent reduction in population and range fragmentation; until the early 20th century the southern migratory birds occupied a much larger and continuous range. Thus, the subspecies rowani may well be abandoned.[6]
The two southern U.S. resident populations are somewhat more distinct, while the Cuban population has been comparatively little studied but appears to have been established on the island for a long time. These and the migratory Greater Sandhill Crane proper form a group of lineages that diverged much more recently from a range in the southern U.S. and maybe northern Mexico, where they would have been resident. The southern migratory population would then represent a later re-expansion which (re-)evolved their migratory habits independent from the northenmost birds, the geographically separated populations expanding rapidly in numbers when more habitat was available as the last ice age ended.[6]
[edit] Distribution and ecology
Their breeding habitat is marshes and bogs in central and northern Canada, Alaska, part of the midwestern and southeastern United States, Siberia and Cuba. They nest in marsh vegetation or on the ground close to water. The female lays two eggs on a mound of vegetation, but it is rare that both chicks hatch and grow to independence[6]. Cranes mate for life; both parents feed the young, called "colts", who are soon able to feed themselves. The Sandhill Crane does not breed until it is two to seven years old, and the average generation time is 12.5 years[6]. It can live up to 25 years in the wild; in captivity it has been known to live more than twice that span. Mated pairs stay together year-round and migrate south as a group with their offspring.
These birds forage while walking in shallow water or in fields, sometimes probing with their bills. They are omnivorous, eating insects, aquatic plants and animals, rodents, seeds and berries. Outside of the nesting season, they forage in large flocks, often in cultivated areas. In many western states and provinces of Canada, Sandhill Cranes are hunted during waterfowl seasons. The meat is reportedly among the better-tasting gamebirds.[citation needed]
The Florida subspecies is often seen in residential yards, and these birds seem little afraid of human approach. These visitors will eat shelled corn and commercially purchased bird seed from the ground and from feeders. They may be seen in yards in north-central Florida virtually year-round, often in pairs that may be accompanied by a juvenile.
[edit] Status and conservation
Though the Sandhill Crane is not considered threatened as a species, the three southernmost subspecies are quite rare. While the migratory birds could at least choose secure breeding habitat, the resident populations could not, and many subpopulations were destroyed by hunting or habitat change. However, initially the Greater Sandhill crane proper suffered most from persecution; by 1940 probably fewer than 1,000 birds remained. They have since increased greatly again, though with nearly 100,000 individuals they are still less plentiful than the Lesser Sandhill Crane, which numbers over 400,000 individuals, making the species the most plentiful crane alive today.[9]
The subspecies pratensis is far less common, with some 5,000 individuals remaining. They are most threatened by habitat destruction and probably depend on human management in the long run. The Mississippi Sandhill Crane has most drastically declined in range; it used to occur along most of the northern Gulf of Mexico coast and its range was at one time nearly parapatric with that of its eastern neighbor (compare the Mottled Duck); today only some 150 remain in an intensively managed population, but this seems at least stable in recent times. Some 300 Cuban Sandhill Cranes remain; this is the least-known of the populations.[9]
The Mississippi Sandhill Crane has become the first bird to have a young hatched where an egg was fertilized by a sperm that was previously thawed out from a cryogenic state. This occurred at the Audubon Institute as part of this subspecies' Recovery Plan.
Sandhill Cranes have been used as foster parents for Whooping Crane eggs and young in reintroduction schemes for that species. This project failed as these foster-raised Whooping Cranes imprinted on their foster parents and later did not recognize other Whooping Cranes as their conspecifics – attempting instead, unsuccessfully, to pair with Sandhill Cranes.
[edit] Gallery
 Breeding pair[verification needed] at Yellowstone National Park |
 Adult with colt |
 At Bosque del Apache |
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 At Bosque del Apache |
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 Sandhill Cranes at Hontoon Island State Park |
 Sandhill Crane at Hillsborough River State Park |
 Florida Sandhill Cranes grazing with young on a golf course in central Florida |
[edit] See also
[edit] Footnotes
- ^ Quantic & Hafen (2003): p.84
- ^ E.g. The Nature Conservancy: Sandhill Crane. Retrieved 2008-JAN-16.
- ^ Volz (2003)
- ^ Miller (1944)
- ^ Miller & Sibley (1942), Brodkorb (1967)
- ^ a b c d e f Rhymer et al. (2001)
- ^ Tacha et al. (1992)
- ^ Brodkorb (1967): pp152-153
- ^ a b Archibald & Meine (1996), Rhymer et al. (2001)
[edit] References
- Archibald, George W. & Meine, Curt (1996): 7. Sandhill Crane. In: del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (eds.): Handbook of Birds of the World (Volume 3: Hoatzin to Auks): 85, plate 5. Lynx Edicions, Barcelona. ISBN 84-87334-20-2
- BirdLife International (2004). Grus canadensis. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes justification for why this species is of least concern
- Brodkorb, Pierce (1967): Catalogue of Fossil Birds: Part 3 (Ralliformes, Ichthyornithiformes, Charadriiformes). Bulletin of the Florida State Museum 11(3): 99-220. PDF or JPEG fulltext
- Meine, Curt D. & Archibald, George W. (eds.) (1996): Sandhill Crane (Grus canadensis)]. In: The cranes: - Status survey and conservation action plan. IUCN, Gland, Switzerland, and Cambridge, U.K.
- Miller, Alden H. & Sibley, Charles Gald (1942): A New Species of Crane from the Pliocene of California. Condor 44(3): 126-127. DjVu fulltext PDF fulltext
- Miller, Loye H. (1944): Some Pliocene birds from Oregon and Idaho. Condor 46(1): 25-32. doi:10.2307/1364248 DjVu fulltext PDF fulltext
- Quantic, Diane Dufva; Hafen, P. Jane (2003): A Great Plains Reader. University of Nebraska Press. ISBN 0803238029
- Rhymer, Judith M.; Fain, Matthew G.; Austin, Jane E.; Johnson, Douglas H. & Krajewski, Carey (2001): Mitochondrial phylogeography, subspecific taxonomy, and conservation genetics of sandhill cranes (Grus canadensis; Aves: Gruidae). Conservation Genetics 2(3): 203–218. doi:10.1023/A:1012203532300 PDF fulltext
- Tacha, T.C.; Nesbitt, S.A.; Vohs, P.A. (1992): Sandhill Crane. In: Poole, A. & Gill, F. (eds.): The Birds of North America 31: 1-24. Academy of Natural Sciences, Philadelphia, PA & American Ornithologists' Union, Washington, D.C. Online version. doi:10.2173/bna.31 (requires subscription) HTML introduction
- Volz, Becky Lauren Volz (2003): The Biogeography of the Sandhill Crane (Grus canadensis). Version of 2003-DEC-31. Retrieved 2008-JAN-16.
[edit] External links
- International Crane Foundation's Sandhill Crane page
- Crane Meadows Nature Center
- National Geographic's Crane Cam on Audubon's Rowe Santuary
- Bird of the Week: Sandhill Crane - Cornell Lab of Ornithology
- Sandhill Crane Species Account - Cornell Lab of Ornithology
- Sandhill Crane Information and Photos - South Dakota Birds and Birding
- Sandhill Crane Grus canadensis USGS Patuxent Bird Identification InfoCenter
- Watching Sandhill Cranes Make the Journey South from National Public Radio
- Sandhill Cranes in Nebraska - NET Television
- Sandhill Cranes - Florida from jzstudios
- National Geographic's webcam at Audubon Society's Rowe Refuge, Platte River, Nebraska (with audio)
- The Nature Conservancy's Species Profile: Sandhill Crane
- National Audubon Society, Rowe Sanctuary, Nebraska
- Othello Sand Hill Crane Festival
- Sandhill Crane videos on the Internet Bird Collection
- Stamps (for Canada, Cuba) with RangeMap
