This research effort was developed and coordinated by Fernando Villaseñor, who just completed his Ph.D. at the University of Montana (2006) and is currently Professor at the Universidad Michoacana de San Nicolás de Hidalgo in Morelia. This research was part of the larger Western North American Migratory Landbird Project, coordinated by the Sonoran Joint Venture, which is an international effort to protect neotropical migratory birds by identifying, conserving, and restoring riparian forests throughout western North America.
Between 2004 and 2006, Fernando and his crew conducted 1,816 standard 10-minute point counts at 87 locations scattered across 14 major vegetation types in Sonora, Mexico (54 non-riparian sites [944 counts], and 33 riparian sites [872 counts]). Eighty percent of 253 species were detected in riparian, and 72% were detected in non-riparian vegetation. More importantly, riparian bird communities were significantly different from those in non-riparian vegetation types, and 22% of the species that comprise the regional avifauna are restricted to riparian habitat in winter, which is more than any other vegetation type.
Fernando and his crew also conducted 433 point counts distributed among three major river systems, with 218 (50.3%) counts conducted within relatively undisturbed and 215 (49.7%) counts conducted within relatively disturbed systems. The mean number of species and individuals per count did not differ significantly between disturbance conditions. In addition, the mean body condition (body mass/wing cord) of ten species that were mist netted did not differ between disturbance conditions, but the ratio of heterophils to lymphocytes (a measure of stress) in the blood of 4 of 5 species was significantly higher, suggesting that the disturbed sites might be less suitable as overwintering habitat.
We are currently working on a proposal to conduct additional habitat distribution studies and training sessions in Mexico with Fernando and Coro Arizmendi.
For more information, contact Fernando Villaseñor:
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