Below is the abstract from the article containing this video: Non-parental infanticide in a dense population of the Black-billed Magpie (Pica pica) Sang-im Lee, Kyungseon Seo, Wonyoung Lee, Woohjung Kim, Jae Chun Choe and Piotr Jablonski, Journal of Ethology, doi:10.1007/s10164-011-0275-z 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 infan- ticide. Movie clips from inside the nest are shown at: showdetail-e.php?movieid=momo110422pp02a, and For detail, please acccess (The copyright of movie is reserved by each person who registered the movie.)