Siblicide, splayed-toes-flight display, and grappling in the Saker Falcon

We observed two incidents of novel social behavior in the saker falcon (Falco cherrug) in Mongolia. First, we provide an account of a two-week-old saker falcon chick killing its nest mate, the first direct observation of siblicide in the genus Falco. We also report aerial combat between three adult saker falcons including observations of talon grappling, whirling, and Splayed-toes-flight, a previously undescribed social display.