Distinguishing Characteristics

Medium-sized, delicately built heron with dark upperparts contrasting with white breast and belly in all plumages and ages; generally easy to distinguish from other New World herons. The only small North American heron with white underparts and foreneck, slaty dark back and neck. Neck and bill quite slender. Adult length 60–70 cm, wingspan 95 cm, bill 9–11 cm (Palmer 1962). Sexes similar in plumage, but male somewhat larger than female (mean mass of male 415 g, of female 334 g; Dunning 1993, see Appendix 4). For nonbreeding (Basic plumage) individuals, head, neck, wings, and tail slate gray; long feathers on back purplish maroon; breast, belly, rump, and underwing-coverts white; chin white; throat marked with tawny or chestnut. In breeding (Alternate plumage) individuals, both sexes acquire new white head (crest) plumes, mauve to violet neck- and mantle-feathers; rufous tinge more obvious on scapulars, back of neck; fila-mentous plumes of mantle, lower scapular plumes are buff-colored; legs become pinkish; bill and face become bluish at base; bill black at tip. Breeding males have magenta iris during courtship; inner margin of iris rose to scarlet in females (Rodgers 1978a). In nonbreeding males and females, inner iris margin pink; iris brown. Head and neck of immatures mostly russet; wings marked with same.