Wedge-tailed Shearwater  |  

The pale morph and dark morphs side by side. The wedge-tailed shearwater is the largest of the tropical shearwaters. The two colour morphs of the species are dark and pale; the pale morphs predominate in the North Pacific, the dark morph elsewhere. However, both morphs exist in all populations, and bear no relation to sex or breeding condition. The pale morph has grey-brown plumage on the back, head, and upper wing, and whiter plumage below. The darker morph has the same dark grey-brown plumage over the whole body. The species’ common name is derived from the large, wedge-shaped tail, which may help the species glide. The bill is dark and legs are salmon pink, with the legs set far back on the body (in common with the other shearwaters) as an adaptation for swimming. This species is related to the pan-Pacific Buller’s shearwater, which differs much in colour pattern, but also has a wedge tail and a thin, black bill. They make up the Thyellodroma group, a superspecies of the large shearwaters that were for a long time included in the genus Puffinus.