Tree swallows (Tachycineta bicolor) are migratory birds found in North America who feast mostly upon insects like flies. A three year study found that these birds defend their babies in the nest, with males performing more aggression than females, and they defended more strongly against ferrets compared to snakes.

Art by @noraprindle.art

Edited by Isabelle McDonald

Reference:

Winkler, D. W. (1992). Causes and consequences of variation in parental defense behavior by tree swallows. Ornithological Applications, 94(2), 502–520. https://doi.org/10.2307/1369222