Temporal Dynamics of Parental Behavior and Nest Use in Ara chloropterus and Ara macao at an Artificial Nest Box in Peru

Cavity limitations and interspecific competition render large macaws valuable models for elucidating the integration of parental care, pair-bond maintenance, and nest defense across reproductive stages. Through continuous video monitoring of a single artificial polyvinyl chloride nest box in the Tambopata National Reserve, Peru, we quantified the complete breeding cycle of a resident green-winged macaw (Ara chloropterus) pair and the visitation behavior of a sympatric scarlet macaw (Ara macao) pair within the same cavity. We constructed daily time budgets for 17 behaviors, categorized into seven functional groups, from motion-triggered video clips; employed multivariate tests; and generalized additive models with beta error distribution to describe the temporal changes across the five reproductive stages. The resident A. chloropterus exhibited a significant reorganization of parental investment, with early courtship behaviors transitioning to peak nest attendance and sentinel vigilance during incubation and early brooding. In later stages, locomotion increased significantly, associated with chick provisioning, whereas the frequency of allopreening remained relatively constant throughout the cycle. The visiting A. macao displayed a brief, behaviorally rich prospecting phase, characterized by nest inspection and locomotion, followed by a sharp decline in minimal activity. These divergent strategies align with owner–intruder asymmetries and floater dynamics, indicating that artificial cavities can support A. chloropterus breeding, while suggesting that additional cavities may redistribute breeding opportunities among competing macaws, a hypothesis necessitating multi-nest and multi-year evaluation.