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Ramphocinclus brachyurus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA AVES PASSERIFORMES MIMIDAE

Scientific Name: Ramphocinclus brachyurus
Species Authority: (Vieillot, 1818)
Common Name(s):
English White-breasted Thrasher

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(i,ii,iii,v) ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Cosgrove, P., Gilardi, J., Temple, H., Villard, P. & Morton, M.
Facilitator/Compiler(s): Benstead, P., Isherwood, I., Mahood, S., Pople, R., Sharpe, C J, Temple, H., Wege, D.
Justification:
This species has an extremely small range, which is continuing to decline as coastal dry woodland is cleared to make way for agriculture, housing and especially tourism developments. Consequently it warrants Endangered status.

Geographic Range [top]

Range Description: Ramphocinclus brachyurus occurs as two subspecies which differ in plumage and call notes. The nominate race is restricted to the Caravelle Peninsula on Martinique (to France) (Bulens et al. 1994, Temple 2005, P. Feldman and P. Villard in litt. 1998, H. J. Temple in litt. 2003), an area of c.5km2, and race sanctaeluciae occurs on the north-east coast of St Lucia between the Marquis River Valley and Frigate Island Refuge (Keith 1997, J. D. Gilardi in litt. 1999). Until 1993, the thrasher was thought to be restricted to the northern part of this area (Marquis-Dennery Knob), and population estimates and censuses in 1971, 1987, 1992 and 2003 suggested that the population in this northern area may be declining (J. D. Gilardi in litt. 1999, H. J. Temple in litt. 2003). In 1993, thrashers were discovered near the Frigate Island Refuge, and recent research suggests that this site holds the bulk (c.75%) of the global population. A comprehensive programme of searches on Martinique found no new subpopulations anywhere else on the island. Surveys in 2003 and 2004 indicated a global population of 1,300-2,600 breeding adults, 1,100-2,400 on St Lucia and c.200 on Martinique (H. J. Temple 2005). In 2006 and 2007, the St Lucia population still numbered about 1,200 individuals (Young et al. 2010). By 2011, the population on Saint Lucia appeared to be fewer than 900 birds, with under 800 in the southern population (M. Morton in litt. 2012).

Countries:
Native:
Martinique; Saint Lucia
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The population is estimated to number at least 1,300 mature individuals, equivalent to over 1,900 individuals in total.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: On both islands, it inhabits dry and semi-dry woodland and scrub with abundant leaf-litter, often in areas with a clear understorey but sometimes in dense thickets. In the northern part of its range on St Lucia (Petite Anse-Dennery Knob) it tends to occur along ravines and river-valleys, but in the rest of its range on St Lucia and Martinique it also occurs on dry hillsides well away from streams. It tolerates a degree of habitat degradation and is often found in secondary woodland and scrub, but although it is occasionally seen in clearings and smallholders' crop-fields, it does not breed in these man-made habitats (Temple 2005). It typically forages on the ground for invertebrates, small frogs and lizards, also taking berries (Keith 1997, Raffaele et al. 1998). Breeding apparently coincides with the onset of the rainy season, and the bulky open-cup nest is placed 0.5-3 m from the ground, usually in the fork of a thin sapling (Keith 1997, J. D. Gilardi in litt. 1999, H. J. Temple in litt. 2003). Eggs (usually two) are laid from May until August, and thrashers may rear more than one successful brood in a season (Keith 1997, J. D. Gilardi in litt. 1999,  H. J. Temple in litt. 2003). The specie sometimes breeds cooperatively - around one-third of nests have helpers, which are apparently retained offspring from previous years, and may be either male or female (Temple et al. 2009, H. J. Temple in litt. 2003). Chicks leave the nest before fledging, and continue to be fed on the ground (J. D. Gilardi in litt. 1999). On St Lucia, nesting success was 44% in 1997, 55% in 2001, 74% in 2002 and 44% in 2003, suggesting normal levels of nest predation for a tropical passerine (J. D. Gilardi in litt. 1999, H. J. Temple in litt. 2003). It is highly sedentary, and may reside permanently on or near breeding territories (J. D. Gilardi in litt. 1999). It occurs at high densities within its restricted range (Temple 2005), suggesting that it may be at carrying capacity, with population increases being unlikely to occur unless more habitat is created (H. J. Temple in litt. 2006).

Systems: Terrestrial

Threats [top]

Major Threat(s): The main threat to this species is habitat loss, perhaps compounded by the impact of predation by introduced mammals. On Martinique, habitat loss during the colonial era means that the species now has a tiny population restricted to a very small area (Temple 2005). Most of this is effectively protected, although some losses to agriculture, charcoal-burning and housing development continue (H. J. Temple in litt. 2006). On St Lucia, on-going habitat degradation and loss is caused by agriculture, charcoal-burning and wood-cutting, and there are potentially devastating plans to build a highway through the centre of the thrasher's range (J. D. Gilardi in litt. 1999). The Le Paradis resort and golf course is being constructed on St Lucia on a site that is estimated to hold c.25% of the global population (Temple 2005), and tourism development companies will soon own land equivalent to 35% of the global Extent of Occurrence (Young et al. 2010). By 2008, 84 ha (12% of the range of St Lucia's southern sub-population) had been cleared for golf course/hotel construction (M. Morton in litt. 2012). Construction was then halted, but still has planning permission; were it to continue, a projected 248 ha (35% of the southern range) would be lost (M. Morton in litt. 2012). In the northern part of the range on St Lucia, planning permission is being sought for 2 large estates the development of which would result in approximately 1,000 ha (60%) of the northern range being lost (M. Morton in litt. 2012). Small Indian mongoose Herpestes auropunctatus and rats Rattus spp. have been present on both islands since before 1900, implying that the thrasher is able to coexist with these predators, but they may place an unwelcome additional burden on an already small population. Nest-monitoring on St Lucia suggests that levels of nest predation are not excessive, but the situation could be different on Martinique, where rats and mongoose may be more abundant: further research is required. Because the thrasher is confined to narrow areas along the Windward coast, a major hurricane could have a severe impact (H. J. Temple in litt. 2003). Additionally, studies have shown the species to be a poor disperser, and it is likely that individuals cannot pass between the two subpopulations on St Lucia, limiting the potential for one population to "rescue" the other from a significant decline (Temple et al. 2006).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
The well-protected (albeit small) Caravelle Nature Reserve covers part of the species's range on Martinique. It is legally protected on St Lucia, but none of its St Lucian range falls within a protected area. On both islands, studies have been carried out to assess the population and threats, and on Martinique a plan exists to control introduced predators (Bulens et al. 1994, Temple 2005, P. Feldman and P. Villard in litt. 1998). Banding birds has facilitated detailed ecological and population research (Temple 2005, P. Feldman and P. Villard in litt. 1998, J. D. Gilardi in litt. 1999, H. J. Temple in litt. 2003).

Conservation Actions Proposed
Monitor both island populations to assess trends. Establish protected areas and effectively protect coastal dry woodland and scrub within the thrasher's range on St Lucia, and prevent further habitat losses on Martinique. Allow adjacent farmland to regenerate into scrub woodland, providing additional habitat and allowing populations to expand. Conduct further research into the impact of predators on Martinique, and implement the predator control plan if deemed necessary. Control predators on St. Lucia (Young et al. 2010). Enact legislation on St Lucia to protect critical wildlife sites. Consult with the hotel developers on St Lucia to protect suitable areas of thrasher habitat in a private reserve (P. Cosgrove in litt. 2007). Safeguard patches of dry forest to the west and north of the Le Paradis tourism development site in Mandelé. Quantify the impact of the Le Paradis development. Preserve mature dry and riparian forest within the tourism development site in Mandelé (Young et al. 2010). Research the taxonomic status of the two subspecies.


Citation: BirdLife International 2012. Ramphocinclus brachyurus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 25 July 2014.
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