Factors Affecting the Life History, Abundance and Distribution of the Yellow-shouldered Amazon Parrot (Amazona Barbadensis) on Bonaire, Netherlands Antilles
Ph.D. thesis, University of Sheffield, UK
Central repository for biodiversity related research and monitoring data from the Dutch Caribbean
Ph.D. thesis, University of Sheffield, UK
The breeding success of obligate secondary cavity nesting birds, including most parrots, can be limited by the availability and quality of nest cavities. Habitat degradation can reduce the number of large cavity-containing trees. This reduction in available cavities can be exacerbated by destructive nest poaching practices, which leave cavities damaged and unusable. Yellow-shouldered Amazons Amazona barbadensis inhabit degraded dry-forest areas on the island of Bonaire (Caribbean Netherlands), and were suspected to be limited by the number of suitable nesting cavities. We compared two approaches to increasing the availability of nesting sites, measuring occupation rates of 10 nest boxes and 10 repaired natural cavities over three years. While none of the nest boxes were used, two of the restored cavities were occupied within five months of repair, and a third in the following year. Only one of the breeding attempts in restored cavities (33%) was successful, compared to the population average of 56%. Sample sizes are small, but restoring natural nest cavities led to a higher rate of uptake than nest boxes and was a considerably quicker and cheaper intervention. However the effectiveness of this intervention depends on the threat of poaching, and there is a risk that restoring poacher-damaged nests may attract breeding pairs away from safer cavities.
Important Bird and Biodiversity Areas (IBA) map of Bonaire (GIS).
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The Important Bird Area (IBA) programme is an initiative of BirdLife International aimed at identifying, monitoring and protecting a network of key sites for the conservation of the world's birds. On the islands, Bonaire, Sint Eustatius (Statia) and Saba, nine IBAs have been designated in recent years. Prior to this study the boundaries of these areas were imprecisely defined and the specific ecological values of these areas were poorly documented and did not provide sufficient footing for further legal protection. In this report we compile available information, add recently collected field data and precisely define boundaries based on ecological and planning criteria so as to furnish the level of documentation sufficient to allow further legal designation and protection by island governments.
In this report we specifically:
On Saba one IBA is identified: Saba coastline IBA (AN 006). The 2,145 ha IBA of Saba lacks any form of legal designation as a protected area. Its value is especially based on breeding seabirds, most importantly the Red-billed Tropicbird and the Audubon’s Shearwater. In addition to legal designation, measures needed to protect the values of this IBA include eradication or control of predators such as cats and rats, and management of the garbage dump to limit the number of these predators. On Saba no gaps in IBA coverage are identified.
On Sint Eustatius two IBAs are identified: Boven (AN 007) and The Quill (AN 008). In contrast to Saba, the two IBAs of St. Eustatius enjoy almost full legal designation as protected park areas. Based on our findings we propose an extension of the 1,106 ha Boven IBA to include Signal Hill for its concentration of nesting Red-billed Tropicbirds. The problems caused by cats and rats are much less acute on Statia than on Saba. The value of the 472 ha Quill IBA is largely based on the resident breeding landbirds it supports. Key threats include goats and possibly feral chickens.
On Bonaire six IBAs are identified: Washington-Slagbaai National Park (AN 009), Dos Pos (AN 010), Washikemba-Fontein-Onima (AN 011), Klein Bonaire (AN 012), Lac Bay (AN 013), and Pekelmeer Saltworks (AN 014). The IBAs are designated as “nature” or “open landscape” in the Nature Policy Plan Bonaire spatial plan, thus enjoying protection.
Washington-Slagbaai National Park (AN 009). (Size: 7,529 ha.)
The Slagbaai IBA covers a diversity of habitats ranging from coastal lagoons to vegetated hillsides. Key values include its habitat value for Yellow-shouldered Amazon, nesting terns and foraging (West-Indian) Flamingos. Most of the area is legally protected either as an island park or with Ramsar status and actively managed. Key threats include overgrazing by feral goats and pigs. Poaching of the Yellow-shouldered Amazon is also a significant problem. Disturbance of tern colonies also occurs due to inappropriate routing of vehicles close to the important nesting island in the Slagbaai lagoon.
Dos Pos (AN 010) (Size: 293 ha.)
Dos Pos IBA is relatively small and largely has no legal protected status. It is an important freshwater site and is both of importance to resident species of which Yellow-shouldered Amazon is the most threatened worldwide.
Washikemba-Fontein-Onima (AN 011) (Size: 6,286 ha.)
The Washikemba-Fontein-Onima IBA includes critical habitat for the Yellow-shouldered Amazon, nesting terns and the Caribbean Coot. About half the area is legally designated as either as “Island Park” or “Protected Landscape” in the Nature Policy Plan Bonaire.
Klein Bonaire (AN 012) (Size: 2,052 ha.)
The Klein Bonaire IBA enjoys full legal protection being designated as a local conservation area and as an internationally recognized Ramsar wetland. The island and surrounding reef are protected within the Bonaire National Marine Park. It is principally of value as a tern nesting island. The woodlands are recovering since complete removal of goats from the island.
Lac Bay (AN 013) (Size: 2,117 ha.)
The Lac Bay IBA enjoys legal designation both as an island conservation area and as international Ramsar wetland site. The mangroves and salt flats are of local significance to nesting terns and hold a breeding population of the Reddish Egret (IUCN-status Near-Threatened).
Pekelmeer Saltworks (AN 014) (Size 6,197 ha.)
The Pekelmeer Saltworks IBA covers about one fifth of the island of Bonaire. Only the 55 ha “Flamingo Sanctuary” and the Pekelmeer enjoy island legal protected status and Ramsar wetland status, while most of the area is used as saliña by the Cargill company. Key IBA values in this area include the nesting colony of the Caribbean Flamingo, and nesting colonies of various tern species. The construction of isolated islands that will not be subject to industrial traffic along the dikes of the managed ponds should provide suitable nesting habitat for recovery of tern nesting in this area of the island. The Laughing Gull population of Bonaire is expanding largely due to the open landfill. This species predates on tern nests and should be controlled if it continues to expand in numbers.
All in all 18 trigger species occur in the nine IBAs in the Caribbean Netherlands. The IBAs on the Leeward islands of Saba and Sint Eustatius host ten and eleven species respectively. Saba is important for the breeding seabirds Audubon’s Shearwater and Red-billed Tropicbird, species with a high conservation priority. The Saba Coastline IBA is the only IBA in the Caribbean Netherlands that qualifies for Audubon’s Shearwater. Saba’s IBA qualifies for another seven species which are all year-round residents with a restricted world’s breeding distribution. St. Eustatius is important for the breeding seabird Red-billed Tropicbird, as well as another eight species: Bridled Quail-dove, hummingbirds and songbirds with a restricted range. The IBAs on the Leeward island of Bonaire host ten trigger species. Some of Bonaire’s IBAs are important for breeding seabird species with a high conservation priority like Royal, Sandwich, Common and Least Tern. Furthermore Bonaire’s IBAs are important for a number of species with a restricted range, of which Caribbean Coot and Yellow-shouldered Amazon have a high conservation priority.
On Bonaire several areas are identified that host IBA key species or other ecological valuable bird species and currently are not designated as IBA: 1) Ponds north of Dos Pos; 2) Ponds east of Kralendijk; 3) Urban parrot roosts; 4) Seru Largu.
This report is part of the Wageningen University BO research program (BO-11-011.05-016) and was financed by the Ministry of Economic Affairs (EZ) under project number 4308701005.