Use of wildlife water developments by birds in Southwest Arizona during migration

Anecdotal evidence suggests that desert water developments attract birds; however, few studies have focused on the role of surface water in habitat selection by migratory birds. Therefore, we studied bird use of wildlife water developments in the Sonoran Desert of southwestern Arizona, USA, using 2 observational approaches (bird surveys in washes with and without water developments and direct observations at water developments) and 1 experimental approach (direct observations at water sources with and without vegetation cover). In spring 2004, we conducted weekly bird surveys at 3 pairs (with and without water developments) of washes. In spring 2005, we designed an experiment to test whether migratory birds more frequently used water developments with than without vegetation cover. During spring, in both 2004 and 2005, we documented use of water by directly observing birds at 13 existing water developments. We found little evidence to support that water developments were important water sources for migratory birds. Migratory bird communities in desert washes near wildlife water developments did not differ in species richness, relative abundance, or density when compared with washes without water developments. This observation suggests that the wildlife water developments that we studied were not an attractant to migratory birds at the landscape scale. At a finer scale, migratory birds rarely (0.1% of all observations) used water developments and experimental water sources. However, resident bird species frequently were recorded (>69,000 observations) drinking and bathing at wildlife water developments. Based on our observations, we conclude that water developments are an important resource for local bird populations in the Sonoran Desert, USA, particularly during periods of drought.