Cepphus grylle
Silhouette: Sheatherius · PhyloPic
In 3 days <5%
The black guillemot or tystie (Cepphus grylle) is a medium-sized seabird of the Alcidae family, native throughout northern Atlantic coasts and eastern North American coasts. It is resident in much of its range, but large populations from the high arctic migrate southwards in winter. The bird can be seen in and around its breeding habitat of rocky shores, cliffs and islands in single or smalls groups of pairs. They feed mainly by diving towards the sea floor feeding on fish, crustaceans or other benthic invertebrates. They are listed on the IUCN red list as a species of least concern.
Both sexes have very similar appearances with black plumage and a large white patch on the upper side of their wings in summer. The bill is also black, being rather long and slender, while the feet are coral-red. In winter adult underparts are white and the upperparts are a pale grey with the back and shoulders exhibiting barred light grey and white patterning.
The birds breed in solitary pairs or small groups during their breeding season starting in late February and early May. Pairs nest above the high tide mark, usually in cliff crevices or gaps in boulders. Many pairs lack true nests and lay directly on the ground. Breeding pairs will typically lay 2-egg clutches and raise 2 chicks to fledging. The eggs are dull white to pale green, boldly marked with dark spots and blotches. Incubation by both parents typically lasts 28 to 32 days. Once hatched, chicks are covered with black down and receive care from the parents until they fledge aged 30 – 40 days, unaccompanied by their parents. Once fledged, chicks are totally independent and by age three or four years they will begin to re-join their natal colony. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Svalbard | 🇳🇴 Norway | |
| 2 | Acadia National Park | 🇺🇸 United States | |
| 3 | Cape Breton Highlands National Park | 🇨🇦 Canada | |
| 4 | Gros Morne National Park | 🇨🇦 Canada | |
| 5 | Wadden Sea National Park | 🇩🇪 Germany |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Tierpark Hagenbeck | 🇩🇪 Germany | |
| 2 | Oregon Coast Aquarium | 🇺🇸 United States | |
| 3 | National Aquarium | 🇺🇸 United States | |
| 4 | Montreal Biodome | 🇨🇦 Canada |
Rare
Under 5% of wildlife watchers report a Black Guillemot sighting in Wadden Sea National Park on a given day, based on 32 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 233rd most-seen of the 285 birds we can rate there. Over three days the chance rises to under 5%, if each day is a fresh chance.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Black Guillemot in Wadden Sea National Park on a given day, so our monthly data shows no clear season.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Black Guillemot sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
5th of 5
Of the 5 parks where we can rate Black Guillemot sightings, Wadden Sea National Park ranks 5th at under 5%. The best odds are in Svalbard (Norway, about 90%), Acadia National Park (United States, about 40%) and Cape Breton Highlands National Park (Canada, about 30%).
GBIF citizen-science records
It is estimated from how often the Black Guillemot is recorded against all the birds logged in Wadden Sea National Park (32 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.
