Spatial behaviors and seasonal habitat use of the increasingly endangered thick-billed parrot (Rhynchopsitta pachyrhyncha)

Abstract

The thick-billed parrot (Rhynchopsitta pachyrhyncha) inhabits highland pine forests in the Sierra Madre Occidental ranges of northwestern Mexico. Their populations have declined significantly due to habitat loss, illegal hunting and increasing predation. Despite their ecological and cultural importance and increasingly endangered status, the species is highly data deficient. Our study aimed to inform and enhance conservation management strategies for thick-billed parrots with information on their spatial ecology, habitat use, and migratory behaviors. We deployed biotelemetry devices to conduct the first tracking study of wild parrots. Our study revealed that thick-billed parrots are obligate migrators, departing their breeding habitats around October and returning from southern habitats around April. We also identified previously unknown overwintering sites and migratory stopover locations, as well as a new nesting site. The parrots exhibited high spatial variability in range shifting behavior, but all tracked parrots exhibited range shifts during migration, with durations of 3 to 181 days and distances of 173 to 765 km. They traveled in close social groups and migratory routes primarily followed high-elevation forests. Home range analysis indicated smaller breeding site ranges and larger overwintering ranges, possibly reflecting nesting constraints and winter food resource dispersion. Less than 20 % of parrot habitats have formal regulatory protections. Conservation management efforts must focus on increasing protections for nesting areas, overwintering habitats, and migratory stopover sites. As climate change exacerbates regional threats, integrated management plans involving local stakeholders are essential for the parrots' survival and the preservation of their old-growth forest habitats.