Lesser Frigatebird

Lesser Frigatebird (Fregata ariel) is the smallest frigatebird, with extremely long angular wings; adult males have a red throat pouch and females show pale underparts. Body shape, bill structure, plumage pattern and voice provide the strongest field characters. Age, sex and season may alter its appearance, so identification should combine several features and careful direct field comparisons with similar species in the same habitat (Wikipedia, general species account).

It remains airborne over tropical seas, snatching prey from the surface or pursuing other seabirds for food, and nests colonially in trees and shrubs on islands. Its movements and social behaviour vary through the year, with breeding birds generally more dispersed and non-breeding birds gathering where food is concentrated. Japanese records place it within the country's documented avifauna as a resident, migrant or visitor (Wikipedia, general species account; Wildlife of Japan occurrence records).