| Resumo: |
I observed, and documented in detail, Ferruginous Pygmy Owl (Glaucidium brasilianum) predation on a mobbing Fork-tailed Flycatcher (Tyrannus savanna) in south-east Brazil. Events described in this account are supported with original photos. In addition to the predation event, I list 12 mobbing bird species that were alarmed by the presence of this raptor in the study area, including Trochilidae (Eupetomena macroura), Formicariidae (Formicivora rufa), Tyrannidae (Camptostoma obsoletum, Elaenia cristata, E. flavogaster, E. chiriquensis, T. savana, Myiarchus tyrannulus), Turdidae (Turdus leucomelas, T. amaurochalinus, T. rufiventris) and Emberizidae (Coryphospingus cucullatus). The Fork-tailed Flycatcher may represent 35-76.8% of the pygmy-owl body mass (41-80 g), which supports early reports about the predation on relatively large prey by this owl species. Although most authors have suggested that mobbing birds are subject to a low predation risk, this report and others confirmed that these events are not negligible and can be deadly dangerous to the mobbers, and conversely profitable to the raptor.
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