Revealing the unknown world of the endangered Lear's macaw using GPS-tracking data: identification of critical habitats for conservation

Fernanda Riera Paschotto, Erica Pacífico, Thiago Filadelfo, Gabriela Rodrigues Favoretto, Júlia Emi de Faria Oshima, Paulo Cardoso, Francisco Voeroes Dénes

Understanding space use and home range is essential for the conservation planning of threatened species as it helps to assess the suitability, extent, and placement of conservation areas that are imperative for species survival and protection. The Endangered Lear’s macaw (Anodorhynchus leari), a highly mobile frugivore, feeding specialist and endemic to Brazil’s Caatinga dry forest, faces ongoing habitat degradation. In this study, we identified critical habitats by examining the spatial distribution of feeding, resting, and roosting sites and investigating home range size and its temporal variation. We GPS-tracked juvenile macaws and estimated fortnightly home ranges with autocorrelated kernel density estimators. We assessed if extrinsic factors, such as tagging site, seasonality, rainfall and vegetation productivity (proxies for food availability) influenced home range size. Our findings reveal considerable variation in home ranges, with an average of 850.15 km² (1.24-8,549.48 km²). Home ranges expanded significantly during the dry season (mean 1,097.06 km²), representing a 2.14-fold increase from the wet season. We also found that site and season primarily drove home range size, while vegetation productivity and rainfall had limited influence. This suggests that macaw movements may respond to complex interactions between rainfall, landscape composition and configuration, and food availability rather than direct resource fluctuations. This is the first study to estimate home ranges for Lear’s macaw, providing critical insights into its spatial ecology. Our findings underscore the importance of preserving key roosting and feeding areas and highlight the need for continuous monitoring to address threats posed by environmental changes and human activity.