Nest site selection and productivity of a critically endangered parrot, the great green macaw (Ara ambiguus) in an anthropogenic landscape

Nest site selection is the principal way secondary cavity-nesting species mitigate the negative effects of factors such as predation, parasitism and exposure on productivity. High-quality cavities could then be expected to be selected in response to the primary threat to nest success. Understanding how demographic rates are affected by anthropogenic changes to ecosystems is vital if effective conservation management strategies are to be developed and implemented. Large-bodied secondary cavity-nesting birds rely on large cavities in mature trees that are often absent or reduced in anthropogenically disturbed forests. Thus, the availability of high-quality nest sites may be limited for these species, potentially reducing productivity. The aim of this study was to investigate nest-site selection and the effect of nest-site features on productivity in the critically endangered great green macaw (Ara ambiguus) in northern Costa Rica. We show that great green macaws select nest sites according to the characteristics of the cavity and of the tree in which they are located. Moreover, productivity was a function of certain cavity features. We conclude that great green macaws are not reliant on primary forest for nest sites and typically choose cavities in remnant, isolated trees in pasture or young secondary forests.