Reproductive parameters in the critically endangered Blue-throated Macaw: limits to the recovery of a parrot under intensive management.

Igor Berkunsky,Rosana M Aramburu,James D Gilardi,Federico P Kacoliris,Gonzalo Daniele,Carmen P Silva Frias,José A Díaz-Luque,Petra Quillfeldt

doi:10.1371/journal.pone.0099941

Abstract

Rediscovered in the wild twenty years ago, the breeding biology of wild Blue-throated Macaws remains largely unexplored, yet is essential to its effective conservation and recovery. Here, we analyse reproductive parameters in an intensively managed wild population of Blue-throated Macaws, providing the first data on the breeding biology of this critically endangered species. During the six-year study period, 2007–2012, the number of active breeding pairs either remained constant or decreased, depending on the site, and no new breeding pairs were discovered despite extensive searching. We documented nesting attempts in natural cavities in dead palms or live hardwoods, and artificial nest boxes. Egg-laying was concentrated during the end of dry season and the beginning of the wet season, August through December. Hatching failure was the greatest cause of egg losses. Half of the breeding attempts of Blue-throated Macaws produced at least one fledging, on average two, after a 85 days nestling period. An average of 4.3 nestlings per year fledged from all known wild nests combined. Each pair lost roughly 65% of its initial reproductive investment at each nesting attempt. In most successful nesting attempts of individualized pairs, a new nesting attempt was not detected the following year. All monitored breeding pairs showed high nest site fidelity, reusing hardwood-tree cavities and nest boxes. Our findings will aid conservation efforts by refining current actions and prompting new approaches towards the conservation and recovery of the Blue-throated Macaw.

Highlights

Half of the 152 species of Neotropical parrots are threatened or near-threatened with extinction, and most of the remaining species are declining due to exploitation for the pet trade, hunting for food and feathers, and/or habitat destruction [1,2,3]
The Bluethroated Macaw Ara glaucogularis is an Bolivian endemic, and one of the two critically endangered macaw species that still exists in the wild [5,6]
We followed 31 nesting attempts (n = 12 in 2007–2008, n = 2 in 2008–2009, n = 8 in 2009–2010, n = 4 in 2010–2011, and n = 5 in 2011–2012). These nesting attempts occurred in 19 different natural cavities and six wooden nest boxes and one PVC nest box

Summary

Introduction

Half of the 152 species of Neotropical parrots are threatened or near-threatened with extinction, and most of the remaining species are declining due to exploitation for the pet trade, hunting for food and feathers, and/or habitat destruction [1,2,3]. The Bluethroated Macaw Ara glaucogularis is an Bolivian endemic, and one of the two critically endangered macaw species that still exists in the wild (as A. glaucus is possibly extinct and C. spixii can only be found in captivity) [5,6]. In the wild, this macaw is unlikely to number more than 115–125 individuals divided in two subpopulations [7]. Basic reproductive parameters for wild Blue-throated Macaws remain unavailable, yet are fundamental to their conservation and recovery

Methods

Results

Conclusion