Seleção do local de construção de ninhos por Asthenes luizae e sua influência sobre o risco de predação

• Ano de defesa: 2013
• Autor(a) principal: Lilian Cordeiro Praes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Local de nidificação; Sucesso reprodutivo; Asthenes luizae; Predação; Ecologia
• Link de acesso: http://hdl.handle.net/1843/BUOS-97XHXK

The Cipó Canastero, Asthenes luizae, is an ovenbird endemic to campos rupestres of the Espinhaço Range, in Minas Gerais. Aspects of its reproductive biology have been poor studied. The reproductive success of A. luizae is considered one of the lowest among neotropical birds and predation accounts for 33.3% of the losses from their nests. The location of bird nests plays an important role in reproductive success and is determined by an adaptive response to several factors related to nest survival, including predation as an important component. The present study aimed to evaluate the criteria that lead to the choice of nest sites by Asthenes luizae and how the characteristics of the microenvironment at these sites are able to predict the risk of predation for each nest. During the months of October and November 2011 and 2012 was conducted a field experiment in Serra do Cipó, MG. Were used natural inactive Asthenes luizae nests and artificial nest exposed for a period of 21 consecutive days, each containing a canary egg and an artificial plasticine egg. After determining the fate of each nest, were recorded parameters considered relevant to predation risk. We compared the site characteristics of natural and artificial nests to check the occurrence of patterns that may explain the selection of nesting site for the species. Also were built survival models based on the nests location parameters to determine predation risk. Evidences of predation suggest that birds are important agents in the loss of nests. Asthenes luizae seems to select substrates that provide camouflage for nests in areas with a large number of potential nest sites and with high density and high height of vegetation. The models that best explain the variations in daily survival rates include nest density and height of vegetation and microrelief characteristics. The estimated survival for Asthenes luizae nests is only 10% during the incubation period, featur ing an alarming situation for the conservation of this species.