Shetland Skuas

The population of Arctic Skuas has declined by 81% according to the latest report by the British Ecological Society.

The National Seabird 2000  census recorded 2,136 Arctic and 9634 Gt Skuas with 90% of the population in Orkney and Shetland


Full report https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2656.12890

Locations of Arctic skua colonies used in analyses of population trend (n = 33 sites) and annual productivity (underlined, n = 20 sites). Dotted line = southernmost extent of Arctic skua breeding range during Seabird 2000. Overall percentage change in Apparently Occupied Territories (AOTs) between the first and last year surveyed (1992 and 2008–2015) is given for each site (see Supporting Information Table S1 for further details). Symbol sizes are scaled to AOT counts in 1992 (four categories: 0–12, 16–26, 30–66, 101–159). Symbol shape denotes colony type, classified by cliff‐nesting seabird host abundance within 5 km of colony during the Seabird 2000 census: squares = type 1 colonies (>10,000 pairs), circles = type 2 colonies (1,000–10,000 pairs), triangles = type 3 colonies (<1,000 pairs)

Arctic Skuas declined at all the study colonies from 1061 ATO 's (1992) to just 200 in (2015), indicating the largest declines took place in the north with the largest productivity in Handa in NW Scotland.

Attacks on Kittiwakes which had only come down onto a loch to bathe  

Arctic Skua nest next to colonies of seabirds either Arctic Terns, or cliff dwelling birds that usually feed on Sandeels - Puffin, Kittiwake, Guillemot and Razorbill. These skuas rely on stealing food from these birds, this is called Kleptopasrasitism

An Arctic Tern attacks an Arctic Skua

Gt Skuas increased at most sites except Foula where a 24% decline occurred. Its odd that the greatest declines in Arctic Skuas occurred where Gt Skua population were small. Food availability and density of Gt Skua were associated with breeding success of Arctic Skua

Gt Skuas are larger and more powerful that Arctic Skuas , they rely on harassing large birds such as gannet for a free meal

Gt Skua seen off by a Fulmar

The world's Gt Skua population is around 16,000 with 57% being in Scotland (Bird life International 2018) especially in Shetland and Orkney. Around 9,634 ATO (Apparently Occupied Territories) can be found in the UK (2004)

They are very aggressive towards humans and animals that stray onto their breeding grounds, making a head on attack and sometime hitting the intruder with their feet.

Gt Skua population in Shetland has fluctuated with numbers up and down at various throughout the isle. Gannet numbers are increasing so you would think that there would be more fish brought back to young gannets and therefore more opportunities for GT Skuas . Noss for instance has around 25000 Gannets double that of 1970

On Foula in 2015 a lot of cannibalistic predation of well grown chicks was again high, although a census count of 1,846 AOT was 11% higher than 2007

In Shetland, 4 colonies at Hermaness, Noss, Mousa and Fair Isle had 1,747 ATO's in 2013, an increase of 27% since  2007. But on Foula a decrease of 28% occurred between 2000 & 2007 (2,293 down to 1,657 ATO's)

In Orkney, a complete census revealed a 23% decrease between 2000 - 2010 (1,710 ATO's)

Discards from fishing boats used to be an important part of the Gt Skuas diet in Shetland but with the reduction of discards they have now started to either concentrate on attacking Gannet for fish, eating birds such as Puffin or resorting to cannibalism .

Having just taken part in the 2018 Seabird census I am very interested in seeing the current figures

Nesting time

Nesting time is a very stressful time for birds and birders alike. Some birds have already had a rough time throughout the winter, birds such as auks - Puffin, Guillemot and Razorbill spend the winter far out at sea. Others migrate a large distance, spending time down near France, Spain and even Africa

Shags (above) are early nesters, preferring lower ledges on cliffs, not the best spot in early Spring. As often is the case, nests get washed out in high seas, leaving one option, but to re-lay their eggs. Most of all the nests at Sumburgh Head got washed away a few years ago.

Fulmars can be seen back on the cliffs in January, adding life to the otherwise empty cliffs. These are master flyers gliding effortless in even the strongest winds. They build a nest mainly with small stones or make a shallow depression in grassy areas.

The couple of photos above show the brood patch, keeping the eggs nice and warm. These birds have increased over the years and have few predators. The nasty smelling oily liquid shoots out from the tube on the nose , anything that gets coated doesn't last long. These bird defences are said to have stopped the re-introduction of White Tailed Sea Eagles in Fair Isle, with many Eagles covered in the oily substance unable to fly and are possibly the reason why Shetland only has a pair or two of Peregrine Falcons.

                                                            Comfortable ?

One problem for Fulmars is the amount  of plastic they are picking up at sea and digesting which eventually kills them.

Kittiwakes have been having a bad time for many years, all down to the lack of Sand eels. Numbers at Sumburgh head dropped to 1/10 of the 1980 population in recent years and no signs of recovery.

Kittiwakes like a well lined nest with plenty of mud to build and cement the nest. These bird regularly collect mud from the pool at Grutness.

                                                                                                               Tug of war

Mallard young have already hatched out and are seemingly well guarded by their parents, but with Skuas and gulls on the look out for an easy meal, many never survive to adulthood

Birders try and estimate whether its been a good or bad breeding season- more of that to come soon