Active nest sites of Olive-sided Flycatchers (Contopus cooperi)

The Olive-sided Flycatcher (Contopus cooperi) is a highly specialized insectivorous bird in boreal forests that has experienced a steep (~70%) decline in recent decades. Arthropod prey and/or prey availability has been linked to nest success and habitat changes affecting local insect communities could make nest sites unsuitable for breeding pairs. In this study, we compared the diversity and abundance (biomass) of insect communities at currently occupied nest sites and unoccupied historical sites. We collected 109,144 insects from nest sites over three summers, from 2013-2015. We found the diversity of the arthropod community was significantly greater at active nest sites in 2014 and 2015, but there was no difference in arthropod biomass.