干旱区生态环境知识资源中心

We described habitat features at nesting plots of Southwestern Willow Flycatchers (Empidonax traillii extimus) in two study areas in central Arizona, and identified features that discriminated between nesting and non-nesting plots. Flycatchers showed preferences for nest placement close to breaks in the canopy and where there was more foliage at nest height and below; these preferences have also been described for Willow Flycatchers in other parts of the range. Other preferences we identified seemed unique to this region, reflecting the dominance of non-native saltcedar in nesting areas but also that the remaining native woody vegetation serves as an indicator of nesting habitat. High foliage density above the nest may be important for creating a suitable microclimate in the low desert landscape in which these birds nest.