Reproductive ecology and conservation of the Lilac-crowned parrot (Amazona finschi) in Jalisco, Mexico

Abstract

The reproductive ecology and reource requirements of the Lilac-crowned Parrot (Amazona finschi) were studies in the tropical dry forest of the Chamela-Cuixmala Biosphere Reserve, western Mexico. Food resource availability was determined by monthly phenology transects in deciduous and semi-deciduous forest. Resource utilisation by parrots was evaluated through observations of diet, habitat use, and crop samples of nestling. Reproductive ecology was determined through studies of breeding behaviour, nest success, reproductive output and nestling growth rates. There was a significant temporal and spatial variability in food resource abundance, with semi-deciduous forest providing greater food resources for parrots during the dry season, while food resource abundance increased in deciduous forest during the rainy season. A critical period of food resource scarcity occurred in May-June at the end of the dry season. Lilac-crowned Parrots were pre-dispersal seed predators, exhibiting high variability in diet and habitat use, which corresponded with fluctuations in food resource availabity. Nesting bejaviour of the Lilac-crowned Parrot was distinct from most psittacines in the high synchrony of nest initiation, low nes tsite difelity, infrequent feeding visits, and short nest attendance. High nest predation resulted in a low 40% nest success, with a reproductive output on 1.0 fledglings per egg-laying female. Third-hatched nestings exhibited slower growth reates than older siblings, though this did not result in mortality. Finally, there was a significant variation between years in the size and growth rates of nestlings, which corresponded with annual fluctuations in food resource abundance. Many of the distinct aspects of Lilac-crowned Parrot reproductive ecology may be related to food resource availability and predation risks. The results demonstrated the potential influence of environmental factors on parrot reproduction, with fragmentation of semi-deciduous forest impacting parrot populations through food limitation during the dry season, and high rates of nest predation.