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

This article, published in the Journal of Raptor Research, discusses the rare occurrence of tool use by a Peregrine Falcon for nest defense. While tool use is uncommon in non-primate animals, and particularly rare in birds, certain groups of birds are known to use tools. In this case, the Peregrine Falcon dropped rocks as a tool to strike an intruder without making direct physical contact. This is the first documented account of a projectile being dropped by a raptor to make contact with an intruder. [Extracted from the article]