Leptotila verreauxi capitalis, Nelson, 1898

Silva, Héctor Gómez de, Pérez Villafaña, Mónica G., Cruz-Nieto, Javier & Cruz-Nieto, Miguel Ángel, 2020, Are some of the birds endemic to the Tres Marías Islands (Mexico) species?, Bulletin of the British Ornithologists’ Club 140 (1), pp. 7-37 : 26-28

WHITE-TIPPED DOVE Leptotila verreauxi capitalis (vs. L. v. angelica )

Coloration.—Breast colour ‘paler and less red’ in all specimens ( Grant 1965a, 25 male and 21 female capitalis vs. 32 male and 12 female angelica), although the single darkest capitalis was almost indistinguishable from the single palest angelica. Also, 50% of island specimens had more extensive white throats than in all mainland birds, 75% of island birds had fewer and paler brown feathers on the thighs and flanks than 100% of mainland birds, and in c.75% of island birds the vinous breast colour extended less far onto the belly than approximately 75% of mainland birds; ‘hence island birds appear to have a larger, white abdomen’ ( Grant 1965a). The face is whiter due to the ear-coverts being white or whitish vs. usually pale pinkish grey, and because the white forehead reaches further posteriorly and contrasts sharply with the hindcrown / nape / postocular area ( Fig. 17; Nelson 1898). The whiter face recalls Grenada Dove L. wellsi and both that and the more extensive white underparts resemble Caribbean Dove L. jamaicensis . However, unlike those species, the ear-coverts and forehead / forecrown contrast with a pink rather than blue-grey hindcrown / nape / postocular area. Half of Grant’s (1965a) capitalis sample was darker dorsally than 100% of his angelica sample, consistent with Ridgway’s (1916) diagnosis and Fig. 17.

Morphometrics.—Wing, tarsus and bill longer ( Grant 1965a; largest effect size is for bill length of females, score 2) whereas the tail of females is shorter, and in both sexes the white on the tail tip is slightly shorter (score 1). The presence vs. absence of sexual dimorphism in tail length is a further difference between capitalis and angelica.

Reasons for uncertainty.—The whiter underparts and face of capitalis resemble L. verreauxi decolor , L. v. decipiens and some L. v. verreauxi (e.g. hbw.com/ibc/1016351 and hbw.com/ ibc/996812 from Costa Rica, hbw.com/ibc/980837 from Colombia and hbw.com/ibc/1086049, hbw.com/ibc/1002421 but not darker hbw.com/ibc/1002417 from the Lesser Antilles). Occasional White-tipped Doves from scatered localities in mainland Mexico resemble capitalis (e.g. htps://macaulaylibrary.org/asset/55312471, htps://macaulaylibrary.org/ asset/57930541, htps://macaulaylibrary.org/asset/57744481, and htps://macaulaylibrary. org/asset/39082171) at least in some features (e.g., htps://macaulaylibrary.org/asset/25545561 with whitish ear-coverts but forehead / forecrown showing litle contrast; or htps:// macaulaylibrary.org/asset/43367021 with forecrown less extensive and pinker breast, or htps://macaulaylibrary.org/asset/32166601 with very whitish flanks but strongly pinkish breast, malar region and ear-coverts). We hypothesise that the mutation(s) responsible for a whitish face and underparts contrasting with the mid-crown / nape / postocular area have arisen independently several times in Leptotila , becoming fixed in capitalis, decolor, decipiens, Caribbean and Grenada Doves, but not in L. v. verreauxi or other races, similar to other known cases of ‘parallel speciation’ (e.g. Cooper & Uy 2017 and references therein). Clearly more research is needed to understand colour variation in L. verreauxi and relatives.