ABSTRACT
O uso de redes de neblina é um método altamente utilizado entre os pesquisadores devido a sua eficiência na captura de aves e morcegos. No entanto, os animais presos ficam vulneráveis à ação de predadores. Durante a realização de três estudos ornitológicos realizados em um fragmento florestal no sudoeste da Amazônia, foram registrados 15 eventos de predação, com taxa de predação de 1,5%. Entre os predadores, 26,7% (n = 4) dos casos foram relacionados com primatas, 13,3% (n = 2) relacionados com formigas de correição, 13,3% (n = 2) relacionados com uma espécie de gavião não identificado e em 46,7% (n = 7) dos casos os predadores não foram identificados. Evitar o acesso de predadores às redes de neblina e diminuir o tempo de monitoramento das redes são algumas das medidas que podem evitar estes eventos.(AU)
The use of mist nets is a highly used method among researchers due to their efficiency in capture birds and bats. However, trapped animals are vulnerable to predator action. During three ornithological studies carried out in a forest fragment from southwest Amazonia, we recorded 15 predation events, with predation rate of 1.5%. Among predators, 26.7% (n = 4) of the cases were related to primates, 13.3% (n = 2) related to army ants, 13.3% (n = 2) related to an unidentified hawk species and in 46.7% (n = 7) of the cases the predators did not identified. Preventing predator access to mist nets and reducing network monitoring time are some of the measures that can prevent these events.(AU)
Subject(s)
Animals , Birds , Behavior, Animal , Food Chain , HaplorhiniABSTRACT
O uso de redes de neblina é um método altamente utilizado entre os pesquisadores devido a sua eficiência na captura de aves e morcegos. No entanto, os animais presos ficam vulneráveis à ação de predadores. Durante a realização de três estudos ornitológicos realizados em um fragmento florestal no sudoeste da Amazônia, foram registrados 15 eventos de predação, com taxa de predação de 1,5%. Entre os predadores, 26,7% (n = 4) dos casos foram relacionados com primatas, 13,3% (n = 2) relacionados com formigas de correição, 13,3% (n = 2) relacionados com uma espécie de gavião não identificado e em 46,7% (n = 7) dos casos os predadores não foram identificados. Evitar o acesso de predadores às redes de neblina e diminuir o tempo de monitoramento das redes são algumas das medidas que podem evitar estes eventos.
The use of mist nets is a highly used method among researchers due to their efficiency in capture birds and bats. However, trapped animals are vulnerable to predator action. During three ornithological studies carried out in a forest fragment from southwest Amazonia, we recorded 15 predation events, with predation rate of 1.5%. Among predators, 26.7% (n = 4) of the cases were related to primates, 13.3% (n = 2) related to army ants, 13.3% (n = 2) related to an unidentified hawk species and in 46.7% (n = 7) of the cases the predators did not identified. Preventing predator access to mist nets and reducing network monitoring time are some of the measures that can prevent these events.
Subject(s)
Animals , Birds , Food Chain , Behavior, Animal , HaplorhiniABSTRACT
Animals eavesdrop on other species to obtain information about their environments. Heterospecific eavesdropping can yield tangible fitness benefits by providing valuable information about food resources and predator presence. The ability to eavesdrop may therefore be under strong selection, although extensive research on alarm-calling in avian mixed-species flocks has found only limited evidence that close association with another species could select for innate signal recognition. Nevertheless, very little is known about the evolution of eavesdropping behaviour and the mechanism of heterospecific signal recognition, particularly in other ecological contexts, such as foraging. To understand whether heterospecific eavesdropping was an innate or learned behaviour in a foraging context, we studied heterospecific signal recognition in ant-following birds of the Neotropics, which eavesdrop on vocalizations of obligate ant-following species to locate and recruit to swarms of the army ant Eciton burchellii, a profitable food resource. We used a playback experiment to compare recruitment of ant-following birds to vocalizations of two obligate species at a mainland site (where both species are present) and a nearby island site (where one species remains whereas the other went extinct approx. 40 years ago). We found that ant-following birds recruited strongly to playbacks of the obligate species present at both island and mainland sites, but the island birds did not recruit to playbacks of the absent obligate species. Our results strongly suggest that (i) ant-following birds learn to recognize heterospecific vocalizations from ecological experience and (ii) island birds no longer recognize the locally extinct obligate species after eight generations of absence from the island. Although learning appears to be the mechanism of heterospecific signal recognition in ant-following birds, more experimental tests are needed to fully understand the evolution of eavesdropping behaviour.