Читать книгу A Manual of Philippine Birds - Richard C. McGregor - Страница 175

Nostrils pervious, the opening linear or oval; wings long, strong, and pointed; first primary longest; legs and feet moderate; hind toe small and elevated; anterior toes fully webbed. Plumage of the adult simple in color, being white, black, and pearl-gray, rarely brown, usually in large areas. Young gray or mottled, very different in color from the adult. Usually found in flocks and never far from water. Eggs two to four, highly colored; nests usually on the ground or on cliffs; young downy at birth and fed in the nest for some time.8