Great Shearwater vs Pink-footed Shearwater

Great Shearwater

Ardenna gravis

Large849 gMarine

This shearwater is 43–51 cm (16.9–20.1 in) in length with a 105–122 cm (3.5–4.0 ft) wingspan. It is identifiable by its size, dark upper parts, and white under parts, with the exception of a brown belly patch and dark shoulder markings. It has a black cap, black bill, and a white "horseshoe" on the base of the tail. The stiff flight, like a large Manx shearwater, is also distinctive. The only other large shearwaters in its range are the Cory's Shearwater and the all-dark Sooty Shearwater.

ID text from Wikipedia, CC BY-SA 4.0

Photo: TRinaud · CC BY 4.0

Pink-footed Shearwater

Ardenna creatopus

Large744 gMarine

Male pink-footed shearwaters on average are found to be larger than females. However, morphological features such as bill size, tail length, head length, and average body size are found to be linked not only to sex, but to breeding locality. These difference may represent adaptations to environmental conditions such as food availability, prey type/mobility and wind speed. In procellariiformes, larger wing area is generally associated with feeding on highly mobile prey, lower wind speeds, and less abundant more dispersed food sources.

ID text from Wikipedia, CC BY-SA 4.0

Photo: dfaulder · CC BY 2.0

Photos and recordings are credited to their authors under the licence shown. Full profiles: Great Shearwater and Pink-footed Shearwater.