The endangered Yellow-headed Parrot (Amazona oratrix) has experienced a considerable reduction in abundance and distribution. Identifying natural and anthropogenic causes of nest failure is a critical step towards developing conservation actions that increase nest survival. In this study, we examined daily nest survival in relation to temporal, habitat and anthropogenic factors, as well as nest site properties. We monitored nests (n = 124) across 6 study sites in Belize during 2017 and 2018 and independently modeled the effects of predation, abandonment and poaching on daily nest survival rates. Overall, the estimated cumulative nest survival probability was 0.18 (95% CI: 0.12–0.25). Predation was the main cause of nest failure, followed by abandonment and poaching. Our results showed that nest predation and abandonment usually occurred early in the nesting cycle. Day within the nesting season negatively influenced daily survival for abandoned nests and had a quadratic effect on survival for poached nests. Poaching events occurred at a specific date range later in the season, with nests farther from the nearest human settlement having higher daily survival. Findings from this study highlight the additive mortality effect that nest poaching is having on Yellow-headed Parrot populations in Belize and show that managers can anticipate the timing and location of nests most vulnerable to poaching.
Supplementation of nest boxes is a common practice to increase nesting opportunities for cavity nesters, such as psittacids (i.e., parrots), many of whom are species of conservation concern. However, understanding occupancy requirements of most psittacids remains an important challenge for effective conservation actions, including placement of nest boxes in the landscape. This study utilized logistic regression models to investigate factors that influence occupancy of nest boxes by two Amazon parrots in the lowland pine savannas of Belize. We performed combined and separate analyses of nest box occupancy by White-fronted (Amazona albifrons) and Yellow-headed Parrots (Amazona oratrix), in relation to understory cover, localized tree density, frontal visibility from the nest box entrance, tree height, tree canopy cover, nest box entrance orientation, and tree diameter at breast height. Overall, 60% of nest boxes were used by four species of Amazon parrots, with White-fronted and Yellow-headed Parrots accounting for majority of use; 27% and 28%, respectively. Tree height had a strong positive effect on nest box occupancy in the combined species analysis. Speciesspecific analysis revealed that Yellow-headed Parrots occupied nest boxes in taller trees, closer to previously successful nests, while White-fronted Parrots did not show strong preference for any measured characteristics. Our results demonstrate that these two species will utilize artificial nest boxes and specifically highlights the importance of selecting taller trees when installing nest boxes for use by Yellow-headed Parrots. Le positionnement des nichoirs influence l'occupation par les perruches amazones à tête jaune (Amazona oratrix) et amazones à front blanc (Amazona albifrons) dans les savanes de pins du BelizeRÉSUMÉ. L'apport de nichoirs est une pratique courante pour augmenter les opportunités de nidification des espèces cavicoles, comme les psittacidés (tels que les perruches), dont un grand nombre sont menacées. Toutefois, il demeure difficile de comprendre les exigences de la plupart des psittacidés en termes d'occupation des nids afin de mettre en place des mesures de conservation efficaces, notamment en ce qui concerne le positionnement des nichoirs dans le paysage. Cette étude a utilisé des modèles de régression logistiques pour examiner les facteurs qui influencent l'occupation des nichoirs par deux perruches d'Amazonie dans les savanes de pins des plaines du Belize. Nous avons réalisé des analyses combinées et distinctes portant sur l'occupation des nichoirs par les perruches amazones à front blanc (Amazona albifrons) et amazones à tête jaune (Amazona oratrix), par rapport à l'épaisseur de la sous-végétation, la densité locale des arbres, la visibilité frontale de l'entrée du nichoir, la hauteur des arbres, l'orientation de l'entrée du nichoir et au diamètre des arbres à hauteur de poitrine. Globalement, 66 % des nichoirs étaient utilisés par quatre espèces de perruches d'Amazonie, les amazones à front blanc et les amazones à tête jaune rep...
We characterized Caribbean pine (Pinus caribaea var. hondurensis) seedling and juvenile survival in lowland Belizean savannas with respect to environment and fire regimes. Plants in open and densely wooded environments had lower survival after fire. We hypothesize that facilitative or correlative mechanisms might promote positive relationships between shrubs and pine survival. Abstract in Spanish is available with online material.
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