Multi-scale habitat use analysis and interspecific Ecology of the Critically Endangered Black-breasted Puffleg Eriocnemis nigrivestis

The Black-breasted Puffleg Eriocnemis nigrivestis is a hummingbird endemic to Ecuador and considered Critically Endangered, given its limited distribution, low population numbers, and ongoing habitat degradation. We investigated habitat use patterns using landscape and microhabitat variables. In addition, we explored a previously postulated competition hypothesis involving the Black-breasted Puffleg and the Gorgeted Sunangel Heliangelus strophianus. Our results suggest that landscape variables may play a role in the habitat selection process; specifically the distance to nearest forest border seems to have a significant effect on our habitat model. We speculate that, as the species is known to perform seasonal movements, the avoidance of forest border might reduce the physiological stress caused by altitudinal migration. At microhabitat level, Black-breasted Puffleg seems not sensitive to forest structure variables. Our findings suggest that ensuring forest tract connectivity, between the altitudinal extremes of the species' range at the north-western flanks of the Pichincha volcano, might be crucial for survival of the species during its annual cycle. However, non-metric multidimensional scaling (NMDS) indicates that Black-breasted Puffleg and the Gorgeted Sunangel do not overlap spatially, but this finding is not conclusive considering our field observations.