*** Welcome to piglix ***

Buller's shearwater

Buller's shearwater
Bullershearwater.jpg
In Hauraki Gulf (New Zealand), during the breeding season
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Procellariiformes
Family: Procellariidae
Genus: Ardenna
Species: A. bulleri
Binomial name
Ardenna bulleri
(Salvin, 1888)

The Buller's shearwater (Ardenna bulleri) is a Pacific species of seabird in the family Procellariidae; it is also known as the grey-backed shearwater or New Zealand shearwater. A member of the black-billed wedge-tailed Thyellodroma group, among the larger shearwaters of the genus Ardenna, it forms a superspecies with the wedge-tailed shearwater (A. pacificus).

Adults birds are 46–47 cm in length, with a 97–99 cm wingspan, and have been recorded to weigh 342-425 g. 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, under bright light it may appear almost white. With the bird facing upwards, the pattern gives the impression of a broken black "M", with light grey interspersing areas.

The underside is bright white; on the head the upperside's grey extends town to eye height and the white cheeks may shine up conspicuously, as in the smaller shearwaters of Puffinus sensu stricto. The rectrices are blackish and the tail is wedge-shaped; bill and iris are dark. Fledged juveniles already have the adult's colouration; the nestlings are covered in grey down feathers.

Compared to other shearwaters, the species is unusually easy to identify at sea by its combination of considerable size and the distinctive M-shaped banding pattern on its upperside while flying, uniquely among its genus and more akin to some gadfly petrels (Pterodroma), the prions (Pachyptila) and their relative, the blue petrel (Halobaena caerulea). These are all much smaller birds, perhaps two-thirds in length and wingspan and less than half in bulk of Buller's shearwater.


...
Wikipedia

...