Among a collection of birds from Grenada, British West Indies, obtained through the kindness of Mr. W. J. Plowden-Wardlaw, are twenty-eight specimens of the polymorphic Bananaquit of that island, Coereba flaveola aterrima. This population exists in two forms, a normal phase, resembling other West Indian and Neotropical Bananaquits in being dark above with a pale yellowish rump, white superciliary, and mostly yellow below with a dark gray throat patch and greenish olive flanks. This is the form which was called Coereba wellsi, normal form morrisi, by Clark (1905) Proc. Boston Soc. Nat. Hist., 32: 293), and which he reported was very on Grenada; seen but twice on the mangrove flats of Point Saline. This phenotype more nearly resembles C. f. luteola of Tobago, Trinidad and northeastern South America, than the other adjacent island populations of normal Bananaquits, differing, however, in possessing a tumid, bright pink rictal spot, and in having a much darker throat patch, and a duller rump patch. The melanistic phenotype, the type of the name aterrima, is virtually completely black, except for a tendency to paler inner edges to the inner secondaries, a greenish olive tint to the rump, and an oil green tint to the slate-colored feathers of the breast. Immature birds of the normal type tend to have dull brownish upperparts, sometimes spotted with new black feathers, the superciliary partly or predominantly yellow, and lack a throat patch, the whole of the underparts being dull yellow, with sooty bases to the throat feathers. The immature of the melanistic phase is dull, blackish-brown above, paling to an oily yellow suffusion on the dull, brownish rump, and dull, clove brown below, washed with olive green. Apparently the rare occurrence of normal birds among the otherwise melanistic population is confined to two areas on the Island of Grenada (see accompanying map, fig. 1); in the extreme northeast in the Levera area, near Levera Island, Green Island and Sandy Island, and in the southwest, at Point Saline, and near it, on True Blue Estate. This distribution has been noted by previous collectors going back into the Nineteenth Century, and from the meager comparative evidence, it would appear that this is a balanced condition of polymorphism, not transient, as Bond has pointed out (1956). Thus all 'round the Island and wherever it may occur in the interior, the Bananaquit is black. Only at these two discrete points, northeast and southwest, do normal type birds appear, and in general it might well be asserted that they are as uncommon now in these days of better transportation and facilities for field study, as they were in the days of Clark (op. cit.) or even earlier. This evidence is in contrast to the assumption of Huxley (1942) and earlier writers (Meise et al.), that the situation was in imbalance, and that the melanistic phase was replacing the normal phase. In size and tone of coloration, melanistic birds from all over the Island appear similar. There is no difference in color between normal specimens from Point Saline and Levera, or Islands to the north including the near-by Green Island, al-
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Jun 1, 1987
Joseph M Wunderle + 1
Open Access