Habitat use by two specialist birds in high-Andean Polylepis forests

Abstract

Assessment of habitat use for species of conservation concern can lead to important measures for habitat conservation. In high-Andean Polylepis forests (3000–5000 m), two such species are the Giant Conebill ( Oreomanes fraseri) and the Tawny Tit Spinetail ( Leptasthenura yanacensis), two forest specialists confronted with the loss and fragmentation of their habitat. The high degree of habitat specialization with strong confinement to Polylepis forest patches predisposes them to a much lower threshold to habitat fragmentation than more generalist species. In this study, we examined their habitat use. Through the use of principal component analysis and generalized linear models considering the vegetation structure, tree density, ground cover and interior and edge plots, we found micro-habitat use only for O. fraseri. This species was more abundant (foraging and perching) in plots with high presence of mature trees. Also, both species showed strong edge avoidance, regardless of fragment size or vegetation characteristics. Adverse microclimate conditions, such as extreme temperatures during warm or cold periods at edges may be the most probable cause of edge avoidance. The reduction of edge:interior ratio within Polylepis fragments and management measures against mature tree cutting is suggested for the conservation of these two near threatened Andean birds.