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<br />PART I. INTRODUCTION
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<br />If one had to choose a species or subspecies currently on the United States' endangered
<br />species list to symbolize the endangered species program, the whooping crane (Grus
<br />americana) would be a prime candidate. This crane's annual travels are newsworthy and its
<br />story dramatic. It is also a symbol of international efforts to save endangered wildlife.
<br />During the last 50 years, many people have become involved in the sometimes frustrating
<br />attempts to save whooping cranes for future generations to enjoy.
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<br />Management actions in the United States and Canada have resulted in a gradual increase in
<br />their number from a low in 1941 when only 1 5 or 16 remained in the flock wintering in
<br />Texas. In December 1993, there were about 261 whooping cranes, including both wild and
<br />captive populations. The Endangered Species Act of 1973 (16 U.S,C., 1531-1543; 87
<br />Stat, 884), which resulted in establishing the Whooping Crane Recovery Team and
<br />developing this Plan, facilitated further actions on behalf of the species. The whooping
<br />crane was listed as threatened with extinction in 1967 (Fed. Rea. Vol. 32, Number 48,
<br />March 11) and as endangered in 1970 (Fed. Rea, Vol. 35, Number 199, October 13).
<br />Critical habitat was designated in 1978 <.EM, Rea. Vol. 43, Number 94, May 15). Recovery
<br />is implemented cooperatively by Canada and the United States (Lewis 1991).
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<br />A. Description
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<br />The whooping crane is in the Family Gruidae, Order Gruiformes, The closest taxonomic
<br />relatives in continental North America are five races of sandhill crane (G, canadensis), the
<br />lesser <.G.~. cana~ensis), Canadian <y. Q. rowani), greater <y. Q. tabida), Florida <y, J;;"
<br />Dratensis), and Mississippi <y. Q, Dulla) (the last also listed as endangered). The common
<br />name "whooping crane" probably originated from the loud, single-note vocalization given
<br />repeatedly by the birds when they are alarmed,
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<br />The whooping crane is the tallest North American bird; males approach 1.5 m when
<br />standing erect, and exceed the greater sandhill crane in height by 12 to 20 em. Males are
<br />generally larger than females, Captive males average 7.3 kg, and females 6,4 kg. Seasonal
<br />weight variation is considerable, with a maximum in December and January and a minimum
<br />in July and August. External measurements from preserved specimens have been
<br />summarized by Walkinshaw (1973: 166). In appearance, whooping cranes are sexually
<br />monomorphic, However, the guard call vocalization is sexually distinct (98.8 percent
<br />accurate, Carlson 1991) and the vocalization and visual components of the unison call are
<br />sexually distinct (Archibald 1975), Vocal analysis is not sufficiently accurate (64.4 percent)
<br />to identify individual birds (Carlson 1991),
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<br />Adult plumage is snowy white except for black primaries, black or grayish alulae, sparse
<br />black bristly feathers on the carmine crown and malar region, and a dark gray-black.
<br />wedge-shaped patch on the nape. The size of the post-occipital patch varies considerably
<br />between individuals. The black primaries and alulae are not visible when the wings are
<br />folded back, and the plumed, decurved tertials ordinarily conceal the short tail. The strong
<br />bill is a dark olive-gray, which becomes lighter during the breeding season. The area at the
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