Differences in the vertical heights at which two crow species use an urban environment

Abstract

Previous studies have shown that the Carrion Crow Corvus corone is more frequently on the ground and at lower heights than the Jungle Crow C. macrorhynchos. However, whether Carrion Crow uses lower heights by choice has not been confirmed. We studied the heights at which the two species were observed in relation to the availability of structures of various heights in the urban environment of Hakodate, Hokkaido. The result showed that Carrion Crow was observed significantly more often at a lower height than Jungle Crow, regardless of the heights of surrounding structures. Two possible explanations of the height choice of Carrion Crow include: 1) it is associated with their habit of foraging on the ground, or 2) a result of interspecific competition between the two species of crows.