Black-capped Petrel vs White-necked Petrel

In short

The Black-capped Petrel and White-necked Petrel are both medium-sized seabirds with similar flight patterns, but they can be distinguished by their head markings and underwing patterns. The Black-capped Petrel typically shows a distinctive black cap and a contrasting white face, while the White-necked Petrel has a more uniform gray head and neck.

Identification tips

1. Look for the black cap and contrasting white face of the Black-capped Petrel. 2. Note the gray head and neck of the White-necked Petrel. 3. Observe the underwing pattern: Black-capped Petrel has a more pronounced dark 'M' pattern. 4. Consider geographic location: Black-capped Petrel is more likely in the Caribbean, while White-necked Petrel is more Pacific-oriented.

Size

Both species are similar in size, with no significant difference in overall body length or wingspan.

Plumage

The Black-capped Petrel features a black cap and a white face, creating a stark contrast, while the White-necked Petrel has a gray head and neck that blends more uniformly with its body. Underwing patterns also differ: the Black-capped Petrel has a more pronounced dark 'M' pattern on the upper wings, whereas the White-necked Petrel's underwings are less contrasting.

Behaviour

Both species exhibit similar flight behavior, characterized by graceful, arcing flight with occasional glides. They are often seen flying low over the ocean.

Habitat

Both species are pelagic and are typically found over open ocean waters, but the Black-capped Petrel is more commonly associated with the Caribbean and the western North Atlantic, whereas the White-necked Petrel is more often found in the Pacific Ocean.

Voice

Vocalizations are not typically used for field identification at sea, as both species are generally silent when away from breeding grounds.