Stercorarius skua
Silhouette: Liam Quinn (photo) and Albertonykus (silhouette) · PhyloPic
In 3 days <5%
The great skua (Stercorarius skua), sometimes known by the name bonxie in Britain, is a large seabird in the skua family Stercorariidae. It is roughly the size of a herring gull. It mainly eats fish caught at the sea surface or taken from other birds.
The great skua was described from the Faroe Islands and Iceland by the Danish zoologist Morten Thrane Brünnich in 1764 under the binomial name Catharacta skua. It is now placed in the genus Stercorarius that was introduced by the French zoologist Mathurin Jacques Brisson in 1760. The English name and species name "skua" is believed to originate from the Faroese skúvur or skúgvur [ˈskɪkvʊər] and is the only known bird name to originate from the Faroes that has come into regular use elsewhere. In Britain, it is sometimes known by the name bonxie, a Shetland name of Norse origin. The genus name Stercorarius is Latin and means "of dung"; the food disgorged by other birds when pursued by skuas was once thought to be excrement. The species is monotypic: no subspecies are recognised.
Great skuas measure 50–58 cm (20–23 in) long and have a 125–140 cm (49–55 in) wingspan. One study found that 112 males weighed... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Vatnajokull National Park | 🇮🇸 Iceland | |
| 2 | Svalbard | 🇳🇴 Norway | |
| 3 | Doñana National Park | 🇪🇸 Spain | |
| 4 | Wadden Sea National Park | 🇩🇪 Germany |
Rare
Under 5% of wildlife watchers report a Great Skua sighting in Lisbon on a given day, based on 5 verified sightings from GBIF citizen-science data. It is the 181st most-seen of the 186 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 Great Skua in Lisbon on a given day, so our monthly data shows no clear season.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Great Skua 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 4 cities where we can rate Great Skua sightings, Lisbon ranks 4th at under 5%, level with the leaders once rounded. The best odds are in Dakar (Senegal, under 5%), Valencia (Spain, under 5%) and Barcelona (Spain, under 5%).
Same order: Charadriiformes
The closest relatives of the Great Skua that you can see in Lisbon (order Charadriiformes, Shorebirds and Allies) are Yellow-legged Gull (about 40%), Lesser Black-backed Gull (about 40%) and Black-headed Gull (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Great Skua is recorded against all the birds logged in Lisbon (5 verified sightings), 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.
