WSP00190 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I a'J~g39 SECTIONTHREE Whooping Crane reported predation of sandhill cranes by coyotes. Bobcats prey on young whooping cranes in Florida and Texas. Contagious diseases such as avian tuberculosis and avian cholera are threats to whooping cranes (Lewis 1991; FWS 1981). Large concentrations of migrating waterfowl and sandhill cranes (i.e., overcrowding due to habitat loss) likely contribute to the spread of both cholera and tuberculosis. Actions which increase the potential for whooping cranes becoming infected with these diseases represent a threat to the species. Avian cholera is a chronic problem in palustrine wetlands of south-central Nebraska's Rainwater Basin area, often causing die-offs oflarge numbers of waterfowl. Avian cholera has been confirmed in sandhill cranes in three separate instances on the Platte River, though no population outbreaks along the Platte River have occurred. It is known that whooping cranes also are susceptible to avian cholera (FWS 1981); in January 1985, avian cholera was confirmed in a whooping crane from the Rocky Mountain population (Doughty 1989). The threat of transmission of avian cholera to the Platte River may be reduced if flows sufficient to provide a high rate of flushing and dilution are maintained (FWS 1981). Avian tuberculosis has been diagnosed in 7 of 18 (39 percent) wild whooping cranes necropsied at the National Wildlife Health Research Center during the period of 1982-1990 (Lewis 1991). One bird from the Aransas-Wood Buffalo population was confirmed to have tuberculosis, and another from that population was a suspect case. Avian tuberculosis likely exists in small numbers of migratory birds and may be transmitted through direct contact with infected birds (FWS I 987a). Oil spills and toxic contaminants are a potential hazard to the wintering area, due to intercoastal navigation. Three spills by nearby navigation traffic occurred in 1995 alone (Lewis 1996) even though no incident directly affecting whooping cranes or their wintering habitats has yet occurred. Other types of cataStrophic events that contribute to the species endangerment are exemplified by at least one discrete event of direct mortality. A severe storm that struck the Louisiana coast in August 1940 led to the eJCtinction of the only known nonmigratory flock of whooping cranes. Events that could have severe and possibly catastrophic affects on the species are drought on the nesting area; contagious disease within the flock; storms such as hurricanes, tornadoes, or blizzards; or contaminant spills in essential habitats vital to the species. This vulnerability to cataStrophic events has prompted the FWS to undertake experimental efforts to establish additional populations. 3.3 BIOLOGY 3.3.1 Life History Whooping cranes have a maximum longevity of22 to 24 years in the wild, but 35 to 40 years in captivity (FWS 1994). The average age offJrst egg production is slightly over 4 years. They mate for life, but will remate following the death of their mate. _ BnIiDer WlllIdI..1f t:IyrIe feIIv.II SI.. oIUll 68FOD9T286OO1r1.doC 6I2J1999(9:52AM)/URSGWcFS/2 3-3