The Scottish Crossbill bird (Loxia scotica) is a small passerine bird belonging to the finch family Fringillidae. The Scottish Crossbill bird is endemic to the Caledonian Forests of Scotland. The Scottish Crossbill was claimed to be confirmed as a unique species in August 2006, on the basis of having a distinctive bird song.
This race of crossbill is resident to Scotland and is not known to migrate. The race will form flocks outside the breeding season, often mixed with other crossbills.
The Scottish Crossbill bird is a chunky, thick-set finch with a large head and substantial bill. It is characterised by the mandibles crossing at their tips, which gives the group its English name. Scottish Crossbill birds are specialist feeders on conifer cones and the unusual beak shape is an adaptation to assist the extraction of the seeds from the cone. The Scottish Crossbill appears to be a specialist feeder on the cones of pines (Scots pine and Lodgepole pine) and larch.
Adult male Scottish Crossbill birds tend to be red or orange in colour and females green or yellow, however. there is much variation. The Scottish crossbill is listed as the only bird species endemic to the British Isles, which provides a strong incentive to maintain its identity as a separate species. Its taxonomic status is however controversial, with it often being considered a race of either Parrot Crossbill or Common Crossbill, both of which breed within its range. The population is thought to be less than 2000 birds. Scottish Crossbill birds nest in pines or other conifers, laying 2 – 5 eggs during breeding time.
Scottish Crossbill calls can be distinguished by sonograms (A sonogram, also known as an ultrasound, is a computerized picture taken by bouncing sound waves off organs and other interior body parts). This provides the basis for a method to survey crossbills and, for the first time, gain a clear picture of their numbers and distribution in Scotland and help in any conservation programs for the race.
The Scottish Crossbill breeds in the native Scots pine (Pinus sylvestris), Caledonian forests of central Scotland, however, (perhaps surprisingly), it often also breeds in forestry plantations of exotic conifers, notably Larch (Larix decidua and L. kaempferi) and Lodgepole pine (Pinus contorta).
Scotlands conifer woods are home to three types of crossbill –
The Common Crossbill (Loxia curvirostra) – with a small bill best suited to extracting seeds from the cones of spruces.
The Parrot Crossbill (Loxia pytyopsittacus) – with a large bill suited to extracting seeds from pine cones.
The Scottish Crossbill (Loxia scotica) – with an intermediate bill size used to extract seeds from several different conifers.
All three are very similar in both size and plumage.
The current estimate is of less than 2000 birds for its global population and a detailed survey is important to learn what the right conservation and management measures are to protect and conserve the species. The first survey of Scottish Crossbills is due in 2008. In future years, Scottish Crossbills could suffer from the effects of global warming.