Bermuda Petrel Pterodroma cahow

Edward S. Brinkley and Kate Sutherland
Version: 2.0 — Published November 16, 2020


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Broadly, the breeding season spans from October through June.

Pair Formation

The breeding season begins when birds arrive at Bermuda in October.

First Brood

Both adults spend most of December at sea, with the female foraging heavily in preparation for egg-laying, which usually occurs in January.

Nest Site

Nesting is loosely colonial on small islets off Castle Roads. The nest is constructed in a crevice or burrow (most of these now artificial and maintained and monitored by the Senior Terrestrial Conservation Officer and staff).


Structure and Composition

The nest is a bare scrape, occasionally lined with grasses or other plant matter.



Eggs are white.

Clutch Size

Females lay only a single egg.

Parental Care

When returning to the nest, either to feed the chick or for incubation duties, adults come to nest burrows only under the cover of darkness.


Both parents forage at sea to provide food for chick. Nesting birds often commute large distances from breeding to foraging sites.

Fledgling Stage

Departure from the Nest

Chicks fledge by May or early June. The fledgling remains on its own for the last month or so, acquiring juvenile plumage (very similar to adults) and shedding natal down; older fledglings frequently sit at burrow entrance at darkness, appearing to observe the sky for long periods, and exercising wings. As in other gadfly petrels and other small tubenoses, fledgling departs burrow by itself.

Recommended Citation

Brinkley, E. S. and K. Sutherland (2020). Bermuda Petrel (Pterodroma cahow), version 2.0. In Birds of the World (T. S. Schulenberg, B. K. Keeney, and S. M. Billerman, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.berpet.02