Non-parental infanticide in a dense population of the Black-billed Magpie (Pica pica)

Abstract

We report the first case of non-parental infanticide in the Black-billed Magpie Pica pica. Using a video camera installed in the victims' nest, we recorded repeated visits (over 4 days) of an adult (each time one bird) who attacked six nestlings at each visit until they died or were evicted. The nest was one of 58 nests filmed over four breeding seasons. Collected evidence suggests that the perpetrator(s) might have been the female breeder of the neighbouring nest, possibly also her male partner. The parental female aggressively attacked the perpetrator. Post-infanticide expansion of breeding territory by the suspected perpetrator is the hypothetical ultimate explanation of the observed infanticide. Movie clips from inside the nest are shown at: http://www.momo-p.com/showdetail-e.php?movieid=momo110422pp01a, http://www.momo-p.com/showdetail-e.php?movieid=momo110422bm01a, http://www.momo-p.com/showdetail-e.php?movieid=momo110422pp02a, and http://www.momo-p.com/showdetail-e.php?movieid=momo110422pp03a. © 2011 The Author(s).