Predator Activity and Nest Success of Willow Flycatchers and Yellow Warblers

摘要: Willow flycatchers (Empidonax traillii) and yellow warblers (Dendroica petechia) are riparian-dependent species that have declined throughout much of their former range in California, USA. These declines been primarily associated with the loss riparian breeding habitat, increases brood parasitism, nest predation. We (1) identified potential predators using inactive warbler nests; (2) determined relationship meadow wetness, size, amount edge to predator activity; (3) association between activity success; (4) how proximity forest isolated trees was related success. used automatic cameras monitor nests baited zebra finch (Taeniopygia guttata) eggs identify predators. track plates (mammalian), point counts (avian), time-constrained searches (reptilian) assess photographed short-tailed weasel (Mustela erminea), Douglas squirrel (Tamiasciurus douglasii), lodgepole chipmunk (Tamias speciosus), deer mouse (Peromyscus maniculatus), unidentified chipmunks spp.) depredating eggs. The covered water negatively squirrels. Meadow size activity. positively squirrels, chipmunks, Steller's jays (Cyanocitta stelleri), brown-headed cowbirds (Molothrus ater). Nest predation major cause failure our study. However, only weasels, Clark's nutcrackers (Nucifraga columbiana), jays, Cooper's hawks (Accipiter cooperii), had indices were success either species. distance willow flycatcher success, whereas both success-nests located closer more likely be parasitized and/or depredated. Our results suggest flooding portions meadows may restrict access forest-edge-associated