OpportunityTitle: Evaluating status of native grasslands for masked bobwhites and other endemic birds in the Sonoran Desert of  Mexico
Description: Recent years show rapid declines in populations of masked bobwhite&#146;s (Colinus virginianus ridgwayi). Few, if any, birds remain in Buenos Aires National Wildlife Refuge (BANWR), their sole location within the United States, and numbers continue falling in the one known population within Sonora, Mexico. Causes include habitat loss directly from cattle and buffle grass (Cenchus ciliaris), while climate warming increases droughts and therefore reduces forage and nesting cover. The USF&amp;W along with partners in Sonara, Mexico share a number of goals for the recovery of this species. These include locating other release sites in the U.S. to reestablish a second population, reintroducing two or more populations in Mexico, and maintaining and increasing the existing populations in Mexico (USFWS 1995). These targets require knowing if habitat or populations of remaining bobwhites exist, their location, their size, land ownership and other spatial, biological and social considerations. The subtropical grasslands that formerly occurred in the more mesic portions of the Sonoran Desert in southern Arizona and Sonora, Mexico are extremely endangered ecosystems. . Unadapted to grazing by large herbivores, and requiring periodic fires for their maintenance, these grasslands have been almost entirely replaced by desert scrub or thorn scrub communities when not converted to buffle grass pasture. So pervasive have been these replacements that most of the grassland fauna of these former communities including the white-tailed hawk (Buteo albicaudatus), Rufous-winged sparrow (Aimophila carpalis), and Sonoran green toad (Bufo rentiformis) are now rare species. As above, the principal grassland indicator of these grasslands, the masked bobwhite (Colinus virginianus ridgwayi), may be extinct in the wild. Biologists in the USA and Mexico agree that the persistence of these species hinges on knowing where other populations may endure, and the location and amount of remaining habitat.
GrantorContactEmailDescription: grant_harris@fws.gov
GrantorContactText: Dr. Grant Harris &lt;br/&gt;U.S. Fish &amp; Wildlife Service &lt;br/&gt;PO Box 1306 &lt;br/&gt;Albuquerque, NM  87103 &lt;br/&gt;Phone: 505-248-6817 &lt;br/&gt;Fax: 505-248-6874