Oceanodroma leucorhoa
Silhouette: Richard Crossley · PhyloPic
In 3 days ~10% in a week ~20%
Leach's storm petrel or Leach's petrel (Hydrobates leucorhous) is a small seabird of the tubenose order. It is named after the British zoologist William Elford Leach. The scientific name is derived from Ancient Greek. Hydrobates is from hydōr "water", and batēs "walker", and leucorhous is from leukos, "white" and orrhos, "rump". It was formerly treated in the genus Oceanodroma before that genus was merged into Hydrobates.
It breeds on inaccessible islands in the colder northern areas of the North Atlantic and North Pacific Oceans. The only breeding colony in the Southern Hemisphere is located on Dassen Island in South Africa. It nests in colonies close to the sea in well concealed areas such as rock crevices, shallow burrows, or even logs. It lays a single white egg, which often has a faint ring of purple spots at the large end. This storm petrel is strictly nocturnal at the breeding sites to avoid predation by gulls and skuas, and even avoids coming to land on clear, moonlit nights. The largest colony of Leach's storm petrels can be found on Baccalieu Island off eastern Canada, an ecological reserve with ~1.95 million pairs of the birds at last estimate in 2013. As with European storm petrel, birds breeding at the northern limit of the species' range on the Arctic Circle in Norway have to delay their breeding until autumn to avoid the 24-hour daylight of the high summer. Wikipedia →
Recording0:33
Canada · 2023
© Sean Vanderluit · iNaturalist · CC BY 4.0
Recording0:29
United States · 2026
© Tulipifera-ike · iNaturalist · CC BY-NC 4.0
Recording0:30
2024
Hunter Stevens · iNaturalist · CC0
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Isla del Coco National Park | 🇨🇷 Costa Rica | |
| 2 | Cabo Blanco Absolute Nature Reserve | 🇨🇷 Costa Rica | |
| 3 | Kenai Fjords National Park | 🇺🇸 United States | |
| 4 | Great Bear Rainforest | 🇨🇦 Canada | |
| 5 | Wadden Sea National Park | 🇩🇪 Germany | |
| 6 | Merritt Island National Wildlife Refuge | 🇺🇸 United States | |
| 7 | Olympic National Park | 🇺🇸 United States | |
| 8 | Acadia National Park | 🇺🇸 United States | |
| 9 | Doñana National Park | 🇪🇸 Spain |
Rare
Under 5% of wildlife watchers report a Leach's Petrel sighting in Cabo Blanco Absolute Nature Reserve on a given day, based on 37 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 150th most-seen of the 241 birds we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
January
In that month about 10% of wildlife watchers report a Leach's Petrel in Cabo Blanco Absolute Nature Reserve on a given day, against under 5% in February to December, the lowest months. That is one of Cabo Blanco Absolute Nature Reserve's driest months, with about 40 mm of rain against 560 mm in October.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Leach's Petrel sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 9 parks where we can rate Leach's Petrel sightings, Cabo Blanco Absolute Nature Reserve ranks 2nd at under 5%, level with the leaders once rounded. The best odds are in Isla del Coco National Park (Costa Rica, under 5%).
Same genus: Oceanodroma
The closest relatives of the Leach's Petrel that you can see in Cabo Blanco Absolute Nature Reserve (genus Oceanodroma) are Wedge-rumped Storm-Petrel (about 10%) and Least Storm-Petrel (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Leach's Petrel is recorded against all the birds logged in Cabo Blanco Absolute Nature Reserve (37 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
