Characteristics of Foraging Perch-sites Used by Loggerhead Shrikes

Perch-sites are a necessary component of Loggerhead Shrike (Lanius ludovicianus) foraging habitat, yet little is known about the influence of perch characteristics on perch use. We hypothesized that Loggerhead Shrikes would selectively forage from taller, bare perches with less foliar obstruction to potentially increase prey detection rates. Shrikes in our study area foraged from trees ∼10% taller than those available and on dead or partially dead trees more often than expected (P = 0.005). Deciduous trees with a leafy canopy in summer were more likely to be used when bare in winter. Removing all obstacles to prey detection did not increase perch preference. Shrikes perched more often and for more total time on constructed artificial perches surrounded by dead branches (50% of used; 166 sec/territory) than on treatments with leafy branches (14%; 32 sec) or no branches (36%; 50 sec). Our results suggest trees that are more useful are those with a good view of potential prey and which also provide ...