Opportunistic predation of a Common Scale-backed Antbird (Willisornis poecilinotus) by a Goliath bird-eating spider (Theraphosa blondi) in the Eastern Brazilian Amazon

ABSTRACT

We report the opportunistic predation of a female Common Scale-backed Antbird (Willisornis poecilinotus) entangled in a mist-net by a Goliath bird-eating spider (Theraphosa blondi) in the Brazilian Amazon. We suggest that the predation event occurred for the following combination of reasons: the spider is common in the study area; the bird became entangled at dusk, when the spider begins its activity; and the lowest mist-net shelf was suspended close to the ground. To reduce opportunistic predation events we recommend that it is critical to keep intervals between mist-net checks to a maximum of 15 min in Amazon forests. We also emphasize that attention is required when installing mist-nets to avoid nets touching the ground when animals become trapped in them.

RESUMO

Relatamos a predação oportunista de uma fêmea de rendadinho (Willisornis poecilinotus) presa a uma rede-de-neblina por uma aranha-golias comedora de pássaros (Theraphosa blondi) na Amazônia brasileira. Sugerimos que o evento de predação ocorreu pelas seguintes razões: a aranha é comum na área de estudo; a ave ter sido capturada ao entardecer, quando a aranha inicia sua atividade; e a última bolsa da rede-de-neblina estar suspensa muito próxima do chão. Para reduzir eventos de predação oportunista recomendamos que é fundamental manter intervalos entre as checagens das redes-de-neblina de até um máximo de 15 min na Floresta Amazônica. Também enfatizamos que atenção é necessária quando da instalação de redes-de-neblina para evitar que as redes encostem no chão quando animais estiverem presos.

KEYWORDS:

• Amazon forest
• Araneae
• mist-nets
• Thamnophilidae
• trophic interaction

Acknowledgments

The Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio) and the Federal University of Amapá (UNIFAP) provided logistical support. We thank IBAMA for authorization to conduct research in the ANF (IBAMA/SISBIO permit 47859-2). This work was supported by the Brazilian National Counsel of Technological and Scientific Development (“Conselho Nacional de Desenvolvimento Científico e Tecnológico” -CNPq) [grant number MCTI/CNPQ/Universal 14/2014:446926/2014-0]. We thank the UNIFAP Ethics Committee for approving our project under the principles of ethics and animal welfare (UNIFAP-CEUA certificate 006/2016). We thank Érico Emed Kauano and Sueli Gomes Pontes dos Santos for assistance with logistics during this fieldwork. We thank Wellington Monteiro for his assistance in the field. We are deeply indebted to Cremilson Alves Marques for his assistance during the fieldwork. We thank Alexander Lees, Lia Kajiki and Ildemar Ferreira for the bird identification, and Rogerio Bertani for the spider identification.

Disclosure statement

No potential conflict of interest was reported by the authors.