Recent acquisition of lands that comprise the Northern Jaguar Reserve offer excellent prospects for conserving, managing, and studying populations of birds in a remote region of east-central Sonora, Mexico. This region is thought to be important to both resident and migratory populations of birds because it supports a diversity of environments, is located near the northern edge of vegetation communities with Neotropical affinities, and is one of the largest and least fragmented wildlands in northwestern Mexico. Furthermore, this area is situated along the Rio Yaqui, a vast lowland corridor through rugged mountains that connects northwest Mexico with the borderlands of Arizona and New Mexico and may thereby provide an important pathway for migratory birds. Despite the significance of this region, little information on bird communities is available.
Much of the information on birds that is available in this region was obtained by Bryan Brown while studying bald eagles (Haliaeetus leucocephalus) along the Rios Aros, Bavispe, and Yaqui (Brown and Warren 1985, Brown 1988). Accounts of birds in Brown’s unpublished field notes were summarized and mapped by Russell and Monson (1998). More recently, an expedition led by biologists from the University of Arizona described 80 species of birds along a 185 km stretch of the Rios Aros (below Natora) and Yaqui and in adjacent side canyons during July and August of 2005 (O’Brien et al. 2006). Most recently in April 2007, Peter Warshall, Noel Snyder, and others described bird observations in several portions of the reserve (Warshall 2007). To aid management and conservation efforts on the Northern Jaguar Reserve, I studied bird communities in July and September of 2007. I timed my efforts so I could describe communities of breeding birds, record the first fall migrants, and survey migratory birds during the peak of fall migration.