Black-vented Shearwater vs Sargasso Shearwater

Black-vented Shearwater

Puffinus opisthomelas

Large408 gMarine

Black-vented shearwater adults are around 30–38 cm in length, have a 76–89 cm wingspan and weigh around 400 g. Males are generally slightly larger than females, though the size difference is minimal. Chicks have grey down feathers, lighter around their throat and breast areas. These down feathers lighten slightly over time. Adults have dark brown heads, and dorsal plumages, with lighter ventral plumage (often white with specks and smudges of brown). This is like many other diving and marine bird species, which use countershading as a method of camouflage. Voice: Although there are few records of black-vented shearwater calls, their vocalizations have been likened to a moaning growl, similar to the sound of a dentist's drill and suction. The black-vented shearwater only calls at night, when there is little to no moon. Vocalizations are believed to play a significant role in mating, as the species lacks sexual dimorphism, akin to the Manx shearwater.

ID text from Wikipedia, CC BY-SA 4.0

Photo: Madeleine Claire · CC BY 4.0

Sargasso Shearwater

Puffinus lherminieri

Medium193 gMarine

The Sargasso shearwater is on average 30 cm (12 in) in length—about half the size of the great shearwater (Puffinus gravis)—and weigh 170 g. There is some variation between populations, and the normal size and weight range is 30–33 cm (12–13 in) and 150–230 g (5.3–8.1 oz). The wingspan is 64 to 72 centimetres (25 to 28 in), the tail is around 8.5 centimetres (3.3 in) long, the exposed culmen measures 3 centimetres (1.2 in) or slightly less, and the tarsus is around 4 centimetres (1.6 in) in length.

ID text from Wikipedia, CC BY-SA 4.0

Photo: Ashwin Srinivasan · CC BY 4.0

Photos and recordings are credited to their authors under the licence shown. Full profiles: Black-vented Shearwater and Sargasso Shearwater.