Identification Tips: Adult MALE Ruby-throated Hummingbirds

Bill: Long and thin.
Chin: The chin of these hummingbirds are black.
Throat: Male hummingbirds have bright red throats – or gorgets - that shimmer with brilliant iridescence in the sunlight. Sibley Guides online offers a great explanation of the iridescence of hummingbirds.
Breast: Male Ruby-throated hummingbirds have bright white and unmarked breasts.
Eye: Adult male Ruby-throated hummingbirds have dark eyes. Interestingly, there is a bright white spot just behind the eye -- which in the right light can be noticeable.
Flanks and Underparts: The sides and underparts of the Ruby-throated hummingbirds are gray-green to bright green in color that again shimmer with iridescence under certain sunlight conditions.
Tail: The Ruby-throated hummingbird has a long, pointed tail with a deep notch at the center.