White-crested Elaenia

A large greenbul often found close to the ground in areas with large trees and open understory, and occasionally in forest edge and other more open habitats. Largely olive-green above and greenish-yellow below with a yellow throat, bright blue facial skin around the eye, a large, angular, laterally compressed bill, and a long red tail. Song is a haunting, resonant series of descending whistles, “WHUUUR-WHUUR-WHUUR-WHUR,” with each note often quavering.

Large, dark brown skua with a very robust beak. Several subspecies vary in plumage from largely dark to mottled pale brown. In flight, exhibits a broad white patch on both upperwings and underwings. Usually seen well offshore, less often towards the coast; often follows boats. Lacks the capped appearance of Great and Chilean Skuas, and has darker underwing coverts than those species. The dark morph of South Polar Skua has colder tones and a smaller bill, but field separation is difficult.

An entirely dark petrel that usually has a cross-like shape in flight. Note the large, square head, the thick bill, and the long rear. Critically endangered; nests on cliffs and crevices on the island of Reunion and feeds in the surrounding ocean. The vocalization is an eerie scream, given at night around breeding sites. Separation from several similar species is tricky. Most similar to Great-winged Petrel, and distinguished only by subtle differences, including the heavier head and bill, longer neck and tail, more rounded wing, and less explosive flight. Also similar to Jouanin’s Petrel, but identified by larger size, longer wings that are held straighter, and shorter rear. Separated from Wedge-tailed Shearwater by the much heavier bill, and from dark-morph Trindade Petrel by the lack of a silver flash in the underwing.