RECORDS OF MOBBING BEHAVIOR IN VENEZUELAN WILD BIRDS

Abstract

Mobbing is a survival strategy in which a small bird a(acks larger and more powerful perceived enemies (e.g., potenAal predators) to drive them away from the vicinity. This paper reports and describes mobbing events performed by Venezuelan wild birds, which were recorded opportunisAcally in different localiAes of the country. A total of 31 species from 15 families were recorded in 131 mobbing events. Individual mobbing was the tacAc most frequently recorded in 83 mobbing events (63%) whereas 36 events (28%) involved the addiAonal assistance of conspecifics, and only 12 (9%) involved non-conspecific allies. Birds tended to mob individually when the enemy was flying but they tended to do so as a group when the enemy was perched. Most of the recorded mobbing events (109 events, 83%) served an anA-predatory funcAon, but mobbing was also performed for food resource protecAon (17 events, 13%), and site defense (five events, 4%). Mobbing behavior was recorded during the breeding season in 16 species with 75 mobbing events (58%) occurring in that period. Eight mobber species were also mobbed. Most mobbing events (98%) were iniAated by the weaker species (bird having smaller body size or mass). Important differences were found in body size and body mass between the mobber and mobbed species. In general, a mobber engaged in mobbing against other birds of similar or larger body size (up to 5.6 Ames larger) or larger body mass (up to 117.5 Ames heavier). In most mobbing events (54%) a mobber a(acked birds that doubled it in size, and in 75% of the events, the mobbed bird was three Ames heavier than the mobber. Only the Roadside Hawk Rupornis magnirostris and the Tropical Kingbird Tyrannus melancholicus were exposed to true danger when they were counter-a(acked, and almost caught, by Common Black Hawks Buteogallus anthracinus. The records collected here contribute to the data on mobbing behavior in wild birds worldwide and noAceably improve the repository of available knowledge in Venezuela and the Neotropical region.