Abstract:
The population of Yellow-naped Amazons (Amazona auropalliata) declined by an estimated
50% between 1980 and 2000, and the current population is estimated to be between 10,000 and 50,000.
Poaching of young has been a persistent problem, but the species is also threatened by habitat loss and
degradation. Because most aspects of their life history, behavior, and ecology have not been examined in wild
populations, we studied Yellow-naped Amazons with the following objectives: (1) identify the species of trees
used for nesting, (2) determine the size and potential function of breeding territories, (3) determine nesting
success, and (4) examine their duetting behavior. We located nests at 16 sites on the Pacific Slope of Costa
Rica from 1999 to 2008. We searched for nests from January to May. Every nest was visited at least once and
some nests were visited every 2–3 weeks throughout the breeding season. We also collected territory and
duetting data at one site (Ahogados). The breeding season of Yellow-naped Amazons was during the dry
season (January–May). Yellow-naped Amazons nested in 21 species of trees, but 68% of nests were located in
only five species, and cavities in dead coyols (Acrocomia aculeata) were used most often. We found no
association between breeding success and the species of tree in which birds nested. Mean territory size was
25,578 m2, and these small areas generally consisted of several trees surrounding a nest tree. Pairs continued
to duet throughout the breeding season, suggesting that duetting is important for territory defense. The nest
failure rate in our study was 89%, and most nest failures (64%) were due to poaching for the pet trade. We
recommend immediate population management and conservation actions, including increased law enforcement
to reduce nest poaching, protection of key nesting areas, educational programs, and habitat conservation.
