Use of Stones by the Black-breasted Buzzard Hamirostra melanosternon to Gain Access to Egg Contents for Food

SummaryAumann, T. (1990). Use of stones by the Black-breasted Buzzard Hamirostra melanosternon to gain access to egg contents for food. Emu 90, 141–144.A captive Black-breasted Buzzard Hamirostra melanosternon cracked Domestic Chicken Gallus gallus eggs by using its bill to throw 15–65 g rounded stones at them in order to feed on the contents. The throwing method, feeding and post-feeding behaviour are described. Throwing accuracy improved during a series of trials conducted over 26 days. The egg-breaking activity is discussed in terms of tool usage and in terms of learned versus non-learned behaviour.