Bermuda Petrel

The Bermuda petrel, or Pterodroma cahow, is a gadfly petrel known locally in Bermuda as the cahow, a moniker inspired by its haunting calls. This nocturnal, ground-nesting seabird is the national bird of Bermuda, gracing the nation's currency with its likeness. With a medium-sized body and long wings, the Bermuda petrel boasts a greyish-black crown and collar, dark grey upper-wings and tail, white upper-tail coverts, and white under-wings with a distinctive black edge. The underparts of this bird are pure white.

Identification Tips

When observing the Bermuda petrel, look for its unique combination of a greyish-black crown and collar, dark grey upper-wings, and white underparts. The long wings and tail are also characteristic, with white upper-tail coverts and under-wings edged in black.

Habitat

The Bermuda petrel is a seabird that nests in burrows on isolated, rocky islets within the warm waters of the Gulf Stream, east of North Carolina.

Distribution

Once thought extinct, the Bermuda petrel is now found nesting on four islets in Castle Harbor, Bermuda. It spends the majority of its adult life on the open seas, ranging from the North Atlantic coastal United States and Canada to waters off western Europe.

Behaviour

The Bermuda petrel is a slow breeder and an excellent flier, visiting land only to nest. It spends most of its life at sea, only returning to land after several years to create nests and breed.

Song & Calls

The eerie cries of the Bermuda petrel have given rise to its local name, the cahow. These calls are most often heard during the nocturnal hours.

Breeding

Breeding season occurs from January to June. The Bermuda petrel nests in burrows that are in complete darkness. After years at sea, males return to breeding islands to create nests, while females return after 4–6 years to find a mate. They lay one egg per season, with a 40% to 50% failure rate in hatching. Both parents incubate the egg for 53–55 days, with hatching occurring between May and June. The species is monogamous, with pairs typically returning to the same nest each year.

Similar Species

The Bermuda petrel may be confused with the similar Audubon's shearwater, but can be distinguished by its unique coloration and call.

Diet and Feeding

The diet of the Bermuda petrel consists of small fish, squid, and shrimp-like crustaceans. They feed predominantly in colder waters and have special glands in their nostrils to filter out salt from ingested seawater.

Conservation Status

The Bermuda petrel is classified as Endangered. Conservation efforts, including habitat restoration and the creation of artificial nesting sites, have helped increase its numbers. However, the species still faces threats from habitat erosion, invasive species, and climate change.