A large hummingbird of the Lesser Antilles, unlikely to be confused with other hummingbird species if seen well. Green throat, brillant blue breast, and black chest of the male are striking, particularly when well lit. Several images and videos for this species are available here.
Generally, a large hummingbird for its range, unlikely to be confused with other hummingbird species if seen well. The Antillean Mango (Anthracothorax dominicus) can look similar in poor light, showing similar black belly and green throat gorget; however, both sexes of mango have distinctly different tail patterns relative to this carib.
Male has distinctive bright green gorget bordered by metallic blue, though the blue is visible only under a small suite of lighting conditions. Belly is black, with ventral feathering green flecked with blue.
Female is generally similar to male, with the exception of bill structure and length. Upperparts are a duller green, similar to coloration of the smaller Antillean Crested Hummingbird. Tail feathers are dark blue, appearing black in low light conditions (ML 35654). Bill is slightly downcurved, but straighter than that of the structurally similar and related Purple-throated Carib; the tip of bill is more decurved than is the base, providing the slightly drooped look. Female is longer billed, and generally has bill more decurved.
Bill and feet black.
10.5-12 cm from tip of tail to tip of bill (Raffaele et al. 1998).