SOUTHEASTERN CARIBBEAN BIRDS PHOTO GALLERY

Trinidad and Tobago Field Naturalists' Club         Southeastern Caribbean Bird Alert         Trinidad and Tobago Rare Bird Committee

IDENTIFICATION ESSAY

Caribbean Martin and Gray-breasted Martin (Progne dominicensis and P. chalybea)

The Caribbean Martin breeds in the Greater Antilles (except Cuba), Lesser Antilles and Tobago, and is thought to migrate to South America from October to December. It is a regular migrant in Curacao and Bonaire, occurring only during fall and spring, suggesting that it passes through these islands while migrating between the Greater Antilles and South America. Small numbers are known to winter in Barbados. Vagrants have been reported from the southern Bahamas, Cayman Islands and Trinidad. Although there are unsubstantiated sight records from Guyana, there appear to be no further records from South America, where it may be expected to occur during winter.      The Gray-breasted Martin breeds throughout Central and South America, with northernmost populations migrating southward during the boreal winter and southernmost populations migrating northward during the austral winter.      In the southeastern Caribbean, the Caribbean Martin breeds in Tobago whereas the Gray-breasted Martin breeds in Trinidad. There are at least four records of adult male Caribbean Martins in Trinidad (click here) plus a few reports of possible hybrids, and one unsubstantiated sight record of a Gray-breasted Martin in Tobago. The identification of these two species was discussed by Ridgely and Tudor (1989) and Hill (2002), and is further discussed in this photo essay.      Juveniles.--Juveniles resemble adults but are smaller. Recently fledged juveniles possess a yellow edge to the bill which quickly darkens with age. Juvenile Caribbean Martins closely resemble adult females, which are browner than adult males. Because juvenile Caribbean Martins are smaller, they could easily be mistaken for a Gray-breasted Martin or even a Brown-chested Martin (P. tapera). The dark chest and flanks of juvenile Caribbean Martin is more uniform in colour and contrasts more strongly with the white underparts than in a juvenile Gray-breasted Martin.      Adult males.--Adult males are diagnostic. Both species are glossy bluish-black above. In Caribbean Martin the bluish-black chest and flanks contrast sharply with the white belly and undertail coverts. In Gray-breasted Martin the dark greyish chest grades gradually to white on the belly and undertail coverts, which do not contrast with the flanks.      Adult females.--Adult females tend to have paler upperparts than males. Females of the two species are very similar. In Caribbean Martin the greyish-brown chest extends downward on the flanks, although not as extensively in the male, and contrasts sharply with the white belly and undertail coverts. The border between the dark breast and white belly tends to be pointed in the centre of the breast. In Gray-breasted Martin, the dark greyish-brown chest grades more gradually to white on the belly and undertail coverts without a distinct pointed appearance, and the flanks do not contrast with the belly. LITERATURE CITED Hill, J. R., III. 2002. A guide to sexing and aging Purple Martins. Birding 34:244-257. Ridgely, R. S., and G. Tudor. 1989. The birds of South America. Vol. 1. The oscine passerines. University of      Texas Press, Austin, TX.

Fig. 1. Juvenile (left) and adult female (right) Caribbean Martins at Bon Accord, Tobago, 7 August 2002. Photo © by Floyd Hayes. Note the smaller body size and yellow edges to the bill of the juvenile. Other than the whitish throat of the juvenile, the extent of dusky colouration on the underparts appears similar.

Fig. 2. Juvenile (left) and adult female (right) Caribbean Martins at Bon Accord, Tobago, 7 August 2002. Photo © by Floyd Hayes. These are the same birds illustrated in Fig. 1, but note the pale throat of the juvenile which gives a breast-band effect similar to that of a Brown-chested Martin.

Fig. 3. Juvenile Caribbean Martin at Bon Accord, Tobago, 8 August 2002. Photo © by Floyd Hayes. Again note the yellowish edges of the bill and whitish throat.

Fig. 4. Adult female Caribbean Martin at Buccoo, Tobago, 8 August 2002. Photo © by Floyd Hayes. Note the pale throat of this individual, giving the appearance of brown breast band..

Fig. 5. Adult male Caribbean Martin at Bon Accord, Tobago, 8 August 2002. Photo © by Floyd Hayes. Note the bluish-black breast and flanks contrasting sharply with the white belly.

Fig. 6. Adult male Caribbean Martin at Buccoo, Tobago, 8 August 2002. Photo © by Brett Hayes.

Figs. 7 and 8. Gray-breasted Martins of uncertain age and sex at Grande Riviere, Trinidad, 17 August 2002. Photos © by Floyd Hayes. Although no juveniles were noted in the flock of c. 20 birds, the pale sides of the bill suggest that these birds may be juveniles, but aolternatively may represent reflection of strong sunlight.

Figs. 9-13. Gray-breasted Martins of undetermined age and sex at Grande Riviere, Trinidad, 17 August 2002. Photos © by Floyd Hayes. Due to the lighting conditions these birds appear browner than normal. Note the gradual gradation from a dark chest to the whitish belly and undertail coverts, with no contrasting dark flanks.