Gyrfalcon – Britain’s Rarest Non-Breeding Annual Visitor
This beautiful bird, Gyrfalcon, has been the most prized species in falconry for hundreds of years and Arab enthusiasts have paid enormous sums for this largest of all falcons. Because of the falconry interest, it appears to have declined earlier than other falcons, though it is still just about an annual visitor to Britain from its more northerly breeding range.
Most birds which visit Britain originate from Canada and Greenland and are of the candicans, an almost pure white variety of Falco rusticolus. The bulk of the western Palearctic population, recently estimated at 600—1,000 pairs excluding the Soviet Union, is basically sedentary, though some wandering does occur.
Further east, Russian birds move south more frequently and there is no evidence that Icelandic birds leave the country. It is generally birds from Greenland which come to Britain via Iceland, white birds having been recorded as far south as Portugal, Spain, and northern Italy.
Some southern European records are undoubtedly escapes from falconers. Gyrfalcons come mostly to western Britain and Ireland. They are most likely to be seen in Shetland, northern Scotland, Cornwall, Devon and the Isles of Scilly in March, but there is a further peak in November-December.
Gyrfalcon – Bird Facts and Information
Recent studies have shown that the species is not as scarce as once thought, for it is very secretive throughout its circumpolar range. Nest-robbing for falconry has been prevalent in some areas but overall the population seems to have stabilized.
Environmental poisoning has not been significant as the species mostly lives in very remote areas. Inland the gyrfalcon’s main prey consists of about 92% ptarmigan and grouse by weight, but there is considerable local variation, and cyclical abundance of rodents such as lemmings can contribute to greater breeding success, with more young fledging.
Some birds concentrate on prey from large seabird colonies, and coasts are a favourite haunt of wandering birds in winter. The gyrfalcon has deceptively slow wingbeats but in level flight, it can overtake a peregrine, and prey is often caught on the wing. Some species such as owls, skuas and gulls try to rise up above the falcon, but when the prey is sufficiently tired the gyr then takes them spectacularly through a rapid ascent.