Effects of nest-site selection, brood parasitism, and predation on the nesting success of passerines breeding in bottomland hardwood forests in east-central Arkansas

There is a need to understand the nesting ecology of passerines, as several populations are declining throughout North America. Habitat loss, brood parasitism, and predation contribute to these declines. During summers 2010-2012, I monitored 282 nests for 10 passerine species in bottomland hardwood forests in east-central Arkansas. Video camera systems were deployed at 81 nests to observe and quantify prey delivery rates and nest fate. I measured vegetation at nest sites and random-paired sites to determine if vegetation influenced nest-site selection, parasitism, predation, or nest success. Mean percent understory vegetation was important for nest-site selection of passerines. Additionally, 26.2% of nests were parasitized by Brown-headed Cowbirds. Mean prey delivery rates were higher for parasitized and successful nests. Nine species depredated nests and Black Ratsnakes were most prevalent. Increased understory vegetation density likely provided passerines with greater nest concealment; however, this did not reduce the probability of parasitism and predation.