Brown Booby

Female brown boobies are slightly larger than males, with an approximate wingspan of 150 cm and average weight of 1.3 kg (140 cm and 1.0 kg for the male). The head, neck, back and top side of wings are a uniform chocolate brown in colour. The brown finishes abruptly across the breast, with the belly and undersides of the wings being white, apart from broad brown edges to the underwing. The legs are yellow shading slightly green. The bill is long and conical. Facial skin colour differs between the sexes, with the male having blue skin and blue-grey bill and the female yellow skin and the bill yellow shading to grey. Immature and juvenile birds differ from adults in having the underparts mottled brown or grey, though still sharply separated from the chocolate brown breast and upperparts.