Cooperative hunting in the Australian Raven with a large fruit bat as the target prey

Abstract

Avian predation is a major cause of natural mortality in bats. This study presents an observation of a group of Australian Ravens Corvus coronoides swooping upon a fully-grown Black Flying-fox Pteropus alecto and successfully dislodging it from its perch. The ravens were able to bring the bat to ground level by cooperatively sustaining bombardments to prevent the bat from taking flight after it lost its hold of the foliage. This observation is significant considering that current documentation on predation by Australian Ravens and other corvids mostly pertains to insects, arachnids and molluscs. Reports of corvids feeding on larger prey typically relate to scavenging carrion or targeting weakened individuals. An adult Black Flying-fox, with a body mass of 500–950 g and head-body length of 24–28 cm, is a novel food item, especially in this case where the bat had displayed no visible signs of sickness or external injuries that would suggest it was a weaker target than conspecifics in the same colony.