TITLE:
Morphological Variation in the Martinican Subspecies White-Breasted Thrasher (Ramphocinclus brachyurus brachyurus)
AUTHORS:
Steven Philippe Son, Thomas Alexandrine, Sébastien Motreuil, Daniel Imbert, Jean-Raphaël Gros-Désormeaux
KEYWORDS:
Caribbean, Endemic Rare Species, Morphological Measurements, Sample Size Effect, Sexual Dimorphism, Subspecies
JOURNAL NAME:
Open Journal of Animal Sciences,
Vol.12 No.1,
November
9,
2021
ABSTRACT: The White-breasted Thrasher (Ramphocinclus brachyurus) is the
smallest passerine bird in the Mimids family. Ranked as “endangered” in the
IUCN list, the demographic distribution of this species is spread unevenly
across two islands in the Lesser Antilles. The Saint-Lucian subspecies, Ramphocinclus brachyurus sanctaeluciae,
was estimated to number between 1200 and 1700 individuals, whereas the
Martinique subspecies, Ramphocinclus brachyurus brachyurus, was estimated at
between 200 and 400 individuals. As an endemic rare species with a high risk of
extinction, the Martinique subspecies should be regarded as a conservation
priority. The small size of the Martinique subspecies population, its
restricted geographical range, and its narrow habitat tolerance make it quite
difficult to study. The variability of morphological traits in this subspecies
has not been biostatistically analyzed recently. In order to update knowledge and fill in any gaps, we have used the
morphometric approach to study the morphological variability of the Martinique
subspecies. The study site is a small peninsula located in the northeast of the
island of Martinique (French West Indies) known as “la Caravelle”. We captured
63 White-breasted Thrashers which were marked, measured, and sexed before being
released. We did not observe any significant differences between the sexes, signifying an absence of sexual
dimorphism. However, we were able to observe a significant variation in
morphological traits between individuals measured inside and outside the
national protected area of Caravelle. The body mass-tarsus ratio was
equal at both sampled sites, something which could potentially be a clue to the
bird’s adaptation to different habitats.