Cooperative hunting of jackdaws by the Lanner Falcon (Falco biarmicus)

Cooperative hunting has been recorded for several subspecies of Lanner Falc on (Falco biarmicus). On average, the success rate for pairs is higher than for single birds. During 1988-90, I collected data on the success of five Lanner Falcon pairs that cooperatively hunted Jackdaws (Corvus monedula) in western Sicily. Fifty-three percent of attacks were aimed at larger groups of Jackdaws. Males made most of the initial attacks (74%) but prey capture s were mainly made by females (87%). Pairs tended not to share prey and use d visual contact to coordinate chases. Most attacks were by partial surpris e (60.8%), followed by nonsurprise (21.6%), and surprise attacks (17.6%). S urprise attacks tended to involve small flocks of Jackdaws, whereas partial surprise tended to involve large flocks.