Date of this Version
Drewien, Roderick C., Wendy M. Brown, and Elwood G. Bizeau. "Sandhill Crane Surveys in the Northern Interior Highlands of Mexico.", In: Stahlecker D. W., ed. 1992. Proceedings of the Sixth North American Crane Workshop, Oct. 3-5, 1991, Regina, Sask. (Grand Island, NE.: North American Crane Working Group, 1992), 174.
Most sandhill cranes (Grus canadensis) wintering in Mexico are found in the northern Interior Highlands of Chihuahua. We surveyed sandhill cranes in the states of Chihuahua and occasionally Durango, Mexico, in winters 1972-90. The population averaged 23,106 (SD = 10,369) in 11 counts at 5-6 areas in Chihuahua. Laguna de Babicora, the most important wetland for cranes wintering in Mexico, had the largest numbers (X = 16,012), followed by Ascension (x = 2,405) and Laguna de los Mexicanos (x = 1,468). All 3 migratory subspecies were present. The lesser subspecies (G. c. canadensis) comprised 85.7% of the popUlation; the greater (G. c. tabida) and Canadian subspecies (G. c. rowani) comprised the remainder. The Canadian subspecies could not be differentiated from the greater subspecies in field surveys. However, we estimated 20 % of those classified as large cranes may have been the Canadian SUbspecies. The lesser subspecies averaged 9.9 % young, and families had a mean of 1.16 young. The 2 larger subspecies averaged 7.6% young, and families averaged 1.15 young. The proportion of the 2 larger subspecies in winter flocks was higher (p < 0.(01) in northern Chihuahua than at winter sites farther south. Lesser and Canadian sandhill cranes wintering in Chihuahua and Durango belong to the western subpopulation of the mid-continent popUlation which mixes annually with greater sandhill cranes from the Rocky Mountain popUlation. From greater sandhill cranes banded and coIormarked in Rocky Mountain states, we received 11 band recoveries and observed 29 color-marked cranes at 7 areas in Chihuahua and at 1 site in Durango. The future security of some wetlands, especially Laguna de Babicora, is uncertain due to proposed habitat alterations. Major alterations of these wetlands would have serious adverse impact on many species of aquatic migratory birds, including several endangered species using these areas in the Mexican Interior Highlands.