Black-bellied Storm-Petrel vs Swinhoe's Storm-Petrel

In short

The Black-bellied Storm-Petrel is best identified by its bold black central belly stripe, though this can be hard to see against dark water. Swinhoe's Storm-Petrel lacks this belly stripe and is generally more uniformly dark. Both species are small, dark storm-petrels, but differ in leg length and habitat preference.

Identification tips

• Look for the black central belly stripe on Black-bellied Storm-Petrel, though it may be hard to see.
• Note the longer legs of Black-bellied Storm-Petrel, which project beyond the tail in flight.
• Consider habitat: Black-bellied prefers colder waters, while Swinhoe's is in warmer regions.
• Swinhoe's Storm-Petrel lacks the belly stripe and is more uniformly dark.

Size

Both species are similar in size, typical of small storm-petrels.

Plumage

Black-bellied Storm-Petrel has a distinctive black central belly stripe and darker upperparts, while Swinhoe's Storm-Petrel is more uniformly dark without a belly stripe.

Behaviour

Black-bellied Storm-Petrel exhibits an unusual foraging behavior, skipping off waves using one leg. Swinhoe's Storm-Petrel's foraging behavior is less distinctive.

Habitat

Black-bellied Storm-Petrel prefers colder, sub-Antarctic waters, while Swinhoe's Storm-Petrel is found in warmer northern waters.