Cameras show sciurids visiting white-headed woodpecker nests without depredating contents

Abstract

In western North America, rodents in the family Sciuridae are considered woodpecker nest predators and management to reduce sciurid habitat has been suggested. However, there have been few actual observations of woodpecker nest predation. In 2014, we used passive infrared cameras in an attempt to identify nest predators for white-headed woodpeckers Picoides albolarvatus in Washington. We monitored 17 nests for 4,296 observer-hours and were surprised to document 33 cases in which two putative nest predators—chipmunks Tamias spp. and Douglas squirrels Tamiasciurus douglasii—visited but did not depredate nests. Most nests visited by these rodents were successful (71.4%) and no eggs or nestlings were lost to predation (no partial depredations). Future studies using continuous video surveillance at nests would help identify nest predators of white-headed woodpecker and quantify proportions of nests depredated by different species.