Buller's Shearwater vs Great Shearwater

Buller's Shearwater

Ardenna bulleri

Large407 gMarine

Adults birds are 46–47 cm (18–19 in) in length, with a 97–99 cm (38–39 in) wingspan, and have been recorded to weigh 342–425 g (12.1–15.0 oz). The upperside of Buller's shearwater is bluish grey. A blackish stripe runs from the tertiary remiges to the primary wing coverts. The primary remiges are blackish, also; the two black areas do not meet at the hand, however; the area between them is a rather light grey, and under bright light may appear almost white. With the bird facing upwards, the pattern gives the impression of a broken black "M", with light grey interspersing areas.

ID text from Wikipedia, CC BY-SA 4.0

Photo: Aviceda at English Wikipedia (Original text: Tom (talk)) · CC BY 3.0

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

Photos and recordings are credited to their authors under the licence shown. Full profiles: Buller's Shearwater and Great Shearwater.