Digging into the life of the spot-billed duck in Japan (see my previous blog entry), I found a true ‘first’ of peculiar behaviour in this species, as published by the researchers Tetsuo Shimada, Kazuyuki Kuwabara, Saori Yamakoshi, Tomomi Shichi in Journal of Ethology 20(2), September 2002. Apparently, ducklings not only have to fear ferocious carp. Kuwabara and his colleagues write that:
“The first observations of infanticide by a precocial avian species, Spot-billed Duck (Anas poecilorhyncha), were recorded on a small pond at Yatsu tidal flat, central Japan, from May to June 2000, where six families of conspecific and one Gadwall A. strepera family, respectively, occupied territories. A female Spot-billed Duck with 11 ducklings attacked ducklings of all the other families killing eight conspecifics and three of the Gadwall.”
High breeding density (15.0 families/ha) may have increased the aggression of the mother duck, according to the authors.