Agonistic behavior of Hammond’s Flycatcher (Empidonax hammondii) on Pine Toad (Incilius occidentalis)

Aggression is an important agonistic behavior in animals, with influence on the survival and reproductive success of the species. Flycatchers (Tyrannidae) exhibit highly visible social behaviors, but little has been documented on their agonistic behavior. We recorded an aggressive behavior of Hammond's Flycatcher (Empidonax hammondii) on Pine Toad (Incilius occidentalis) in a pine-oak forest of Omiltemi, Guerrero, Mexico. According to our observation and to what has been reported in the literature for other flycatchers, E. hammondii can present atypical behaviors related to the attack and/or predation of small-sized amphibians.