Bonin Petrel vs Black-winged Petrel

In short

The Bonin Petrel and Black-winged Petrel are similar seabirds, but can be distinguished by key features. The Bonin Petrel has a more contrasting plumage with a distinct white face and underparts, while the Black-winged Petrel displays darker upperparts and a more uniform appearance. Observing their flight patterns and habitat preferences can also aid in identification.

Identification tips

1. Look for the white face and underparts of the Bonin Petrel. 2. Note the dark cap and 'M' pattern on the wings of the Bonin Petrel. 3. Observe the more uniform grayish appearance of the Black-winged Petrel. 4. Consider the location: Bonin Petrels are more likely near central Pacific islands, while Black-winged Petrels are found in the southwestern Pacific.

Size

Both species are similar in size, but the Bonin Petrel may appear slightly bulkier.

Plumage

The Bonin Petrel has a striking white face and underparts with a dark cap and a distinctive 'M' pattern on the upper wings. In contrast, the Black-winged Petrel has darker upperparts and a more uniform grayish appearance, lacking the stark contrast seen in the Bonin Petrel.

Behaviour

Both species exhibit similar flight behavior, characterized by graceful gliding and occasional flapping. However, the Bonin Petrel is more likely to be seen in mixed-species flocks.

Habitat

The Bonin Petrel is typically found in the central Pacific, often around islands like Midway Atoll, while the Black-winged Petrel is more widespread in the southwestern Pacific. Their ranges overlap, but the Bonin Petrel is more associated with island nesting sites.

Voice

Vocalizations are not a primary distinguishing feature in the field, as both species have similar calls, often heard at night near breeding colonies.