The White-breasted thrasher

Which species ?

There are two distinct taxa of White-breasted thrasher Ramphocinclus brachyurus : the sub-species R.b. brachyurus inhabits Martinique where it is limited to a small area covering approximately 5 km² located on the Caravelle peninsula, and the sub-species R.b. sanctaeluciae, which inhabits the north-east coast of Saint Lucia.

White breasted trasher, Martinique, J-M. Fenerole

This discreet passerine favors arid and semi-arid wooded areas and feeds primarily on insects. White-breasted thrashers live mainly in pairs. Their nest is a voluminous construction placed in a tree or bush between 1.5 and 5 meters above the ground, which makes it highly vulnerable to predation and disturbance. The breeding season takes place between the months of April and August, with the female laying two eggs. Currently, very little is known concerning the length of incubation, the time spent on the nest and details about care given to the young by parents. White-breasted thrashers can raise more than one clutch per season. The last count of the species in 2003 indicated that numbers varied between 1,300 and 2,600 nesting adults, with only 200 in Martinique. It is estimated that there are still between 1,100 and 2,400 in Saint Lucia. The White-breasted thrasher is classified as “Endangered” (BirdLife, IUCN, 2008) and in danger of extinction in Martinique.

Why ?

Although the White-breasted thrasher was previously found in other parts of Martinique, approximately 40 remaining pairs, counted in 1990 by Peter Evans, are only present on the Caravelle peninsula. The concentration of populations at a single site, and in this case, a peninsula, makes this passerine endemic to the Lesser Antilles, extremely vulnerable to extinction. Measures taken to date have not made it possible to modify the species’ conservation status, even though the creation of the Caravelle Nature Reserve allowed its numbers to increase and stabilize [1]. Within as well as outside the Reserve, the sites frequented by the species have not been precisely identified, making it impossible to target protection and management efforts.

Our actions

At a Conservatoire du Littoral(Coastal conservatory) site where the species’ breeding habits are well-known, a technique combining probes, in situ captures and a GIS will make it possible to precisely characterize the species’ habitat. Once its ecological requirements have been determined, the sites where the species could potentially be present will be identified throughout the Caravelle peninsula using the same parameterized technique, as sufficient human resources to carry out this work solely on the ground are not available. In the predetermined areas, ornithological monitoring will make it possible to verify the species’ presence. This knowledge will allow the boundaries of the Nature Reserve to be extended to include the newly identified hotspots for the species, analyze the conservation status of each hotspot and lead to appropriate planning and management measures. These management measures and planning could include :

• Closing certain trails and setting up detours, by means of plant and physical barriers
• Information boards on current regulations to reinforce these modifications
• Trapping and localized, targeted poisoning to fight against cats, rats and mongooses
• Installing predation prevention systems around identified nests (PVC tubes around branches framing the nest), etc.

The Martinique Regional Nature Park, the Conservatoire du Littoral(Coastal conservatory) and the GRIMAAG(French West Indies and Guiana Research Group on Computer Science and Applied Mathematics) are the main partners in this component.

Report, involve, raise awareness

The high-tech methodology and the results of this approach will be presented during a seminar on monitoring and assessment tools for avifauna in the tropics which will be held under the project in 2014 in French Guiana. The proceedings of this seminar will be disseminated more broadly to conservation stakeholders in a technical guide published in French, Spanish and English : « Monitoring the Conservation Status of Avifauna in the Overseas Departments : Lessons Learned, Results and Evaluation ».