The foraging behavior of a guild of insectivorous birds in three structurally different communities

Abstract

The foraging behavior of six species of insectivorous foliage-gleaning birds was studied in three different communities in Arizona to examine the role of resource partitioning in coexistence. I recorded data during winter and spring, the harshest seasons. Two to four species coexisted in each community. I recorded plant species, plant life-form, foraging height, plant portion, perch size, capture size, capture technique, and foraging rate. Foraging behavior was compared to the plant distribution profile, interspecifically among sympatric guild members within a season, intraspecifically between seasons, and intraspecifically between communities within a season. Species differed most in plant species selected, foraging height, and capture technique, and varied the least in plant portion, perch site, and capture site. All species overlapped in most behaviors, but differed from other guild members in at least two foraging variables. Permanent residents showed the greatest differences. These findings are consistent with niche complementarity and the idea that competition has led to partitioning of the resources. However, other hypotheses cannot be ruled out.