Rocks Dropped by a Peregrine Falcon (Falco peregrinus) for Eyrie Defense

Tool use in wild non-primate animals is relatively uncommon in the literature (Bentley-Condit and Smith 2010). In birds, tool use is particularly rare, although certain groups of birds are well known users of tools (e.g., Corvidae; Bentley-Condit and Smith 2010). In wild raptors (sensuMcClure et al. 2019), tool use is uncommon and is typically associated with prey exploitation (Bentley-Condit and Smith 2010). Raptors have been recorded using tools for prey or food extraction (Chisholm 1954, Fleming 1955, Van Lawick-Goodall and Van Lawick-Goodall 1966), prey capture (Levey et al. 2004, Bonta et al. 2017), and food preparation (Ellis and Brunson 1993). Although tool use that is not directly associated with prey exploitation is especially uncommon among raptors (Bentley-Condit and Smith 2010), agonism has been noted in the literature and is only known...