AVIS-IBIS

Birds of Indian Subcontinent

Distribution and Abundance of Sandhill Cranes in Mexico

Publication Type:Journal Article
Year of Publication:1996
Authors:Drewien, RC, Brown, WM, Benning, DS
Journal:The Journal of Wildlife Management
Volume:60
Issue:2
Date Published:1996
ISBN Number:0022541X
Keywords:Gruidae, Grus, Grus canadensis, Grus grus
Abstract:We summarized sandhill crane (Grus canadensis [cranes]) counts from Mexico recorded during 23 January aerial waterfowl surveys by the U.S. Fish and Wildlife Service (FWS) between 1953 and 1994. Cranes were recorded at 39 areas in 14 states; 97.4% were in the Northern Highlands, 0.4% in the Central Highlands, 1.5% along the Gulf Coast, and 0.7% on the Pacific Coast. Most wintered in the states of Chihuahua (91.7%) and Durango (4.7%). Total counts of >30,000 cranes were recorded in 1979 and 1994; 70,000 were reported in Chihuahua in February 1947. Laguna de Babicora, Chihuahua, was the most important winter area. We also conducted ground and aerial surveys in Chihuahua during most winters 1970-92 and occasionally in Durango and Sonora. We found a mean of 21,649 cranes at 6 study areas in Chihuahua with highest mean counts at Laguna de Babicora (16,012), followed by Ascension (2,405) and Laguna de los Mexicanos (1,469). Our surveys indicated that >50,000 cranes winter in Mexico. At 6 study areas in Chihuahua, all 3 migratory subspecies were present with the lesser subspecies (G. c. canadensis [lessers]) composing 88.9%. The greater (G. c. tabida [greaters]) and Canadian subspecies (G. c. rowani [Canadians]) composed the remainder but could not be differentiated in field surveys; about 25% of cranes classified as greaters may have been Canadians. Annual recruitment and brood size averaged 10.1% and 1.18 in lessers and 6.5% and 1.14 in greaters. Lessers and Canadians wintering in the Interior Highlands belong to the Western Subpopulation of the Midcontinent Population (MCP), while greaters are from the Rocky Mountain Population (RMP). Based on sightings of marked cranes, band recoveries, and field observations, we estimated that about 10% of the RMP wintered in Mexico in Chihuahua and Durango. RMP cranes were more abundant in northern Chihuahua than at sites farther south (P < 0.001). Gulf Coast cranes are probably Canadians and lessers from the MCP, Gulf Coast Subpopulation. Population affiliations of Pacific Coast cranes are uncertain. Laguna de Babicora, the most important crane wintering area in Mexico, is threatened by proposed habitat alterations. Loss of this wetland would adversely affect cranes and other migratory birds, including several endangered species. Conservation plans and action are needed to protect this key winter site.
URL:http://www.jstor.org/stable/3802225
Short Title:The Journal of Wildlife Management
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