Scottish crossbill | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Class: | Aves |
Order: | Passeriformes |
Family: | Fringillidae |
Subfamily: | Carduelinae |
Genus: | Loxia |
Species: | L. scotica |
Binomial name | |
Loxia scotica Hartert, 1904 | |
The Scottish crossbill (Loxia scotica) is a small passerine bird in the finch family Fringillidae. It is endemic to the Caledonian Forests of Scotland, and is the only terrestrial vertebrate species endemic to the United Kingdom. [2] [3] [4] The Scottish crossbill was confirmed as a unique species in August 2006, on the basis of having a distinctive bird song. [5] [6] [7]
The genus name Loxia is from Ancient Greek loxos, 'crosswise', and scotica is Latin for 'Scottish'. [8] The Scottish Gaelic name for a crossbill is Cam-ghob, which means 'crooked beak'. [9]
The British Ornithologists Union first classed the Scottish crossbill as a separate and distinct species in 1980, but some ornithologists believed there was insufficient scientific research for its status. It was considered to be possibly a race of either the red crossbill or the parrot crossbill, both of which also occur in the Caledonian Forest.
RSPB research showed that Scottish crossbills have quite distinct flight and excitement calls from other crossbills – some even stated they have "Scottish accents".
Research in Scotland has shown that red, parrot and Scottish crossbills are reproductively isolated, and the diagnostic calls and bill dimensions have not been lost. They are therefore good species. [10]
The population is thought to be approximately 20000 birds. [11] It nests in pines or other conifers, laying 2-5 eggs.
The Scottish crossbill breeds in the native Scots pine (Pinus sylvestris), Caledonian forests of the Scottish Highlands, but often also in forestry plantations of exotic conifers, notably Larch (Larix decidua and L. kaempferi) and Lodgepole pine (Pinus contorta).
This species of crossbill is resident, and is not known to migrate. It will form flocks outside the breeding season, often mixed with other crossbills.
The crossbills are characterised by the mandibles crossing at their tips, which gives the group its English name. They are specialist feeders on conifer cones, and the unusual bill 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 males tend to be red or orange in colour, and females green or yellow, but there is much variation.
The Scottish crossbill is extremely difficult to separate from the red and parrot, and plumage distinctions are negligible. The head and bill size is intermediate between and overlapping extensively with the other two, and extreme care is needed to identify this species. The metallic jip call is probably the best indicator, but even this needs to be recorded and analysed on a sonogram to confirm the identity.
According to a lengthy scientific study by the RSPB, 'Celtic' crossbills differ in bill size from other crossbill species found in Great Britain, and they have also been found to have a distinct Scottish accent or call, thought to be the method used by the birds to make sure that, especially given the physical similarities with other crossbills, they only attract and pair with potential mates of the same species.
The most important evidence to come from RSPB's long term study in the Highlands focused on discovering if the birds mate with those with a similar bill size and call, and whether young Scottish crossbills inherit their bill sizes from their parents.
Results showed that of over 40 pairs of different types of crossbills caught, almost all matched closely for bill size and calls, so the different types of crossbills were behaving as distinct species.
The calls can be distinguished by sonograms. 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 programmes for the race.
The first survey of Scottish crossbills was in 2008. [12]
Despite lacking data for population trends, British Birds places the crossbill on their Amber list for conservation concern on the basis of it being an endemic species and therefore of 'international importance'. [13] A 2017 report by the British Trust for Ornithology identified the crossbill as being at high risk of extinction. [14]
Breeding populations exist at Corrimony Nature Reserve, [15] and Loch Garten Nature Reserve, one of the United Kingdom's most protected nature sites. [16]
One of the main threats to the crossbill's habitat is wood and pulp plantations, plus underplanting conifers and grazing pressure. [17]
The main active conservation initiative is the implementation of the EU Biodiversity Action Plan, which seeks to protect the numerous species of birds throughout the EU. Further studies are needed to establish the species of trees crossbill's best adapt to, as well as to establish population trends. It has also been suggested to prevent any further loss of habitat, and further restrict grazing. [17]
Loch Garten is a large Highland freshwater loch near Boat of Garten, in the Strathspey area of the Cairngorms National Park, in Scotland. It is surrounded by the tall pine trees of the Abernethy Forest, a large area of which is an RSPB nature reserve. The loch is renowned for its breeding population of ospreys, which lend Boat of Garten its nickname "The Osprey Village".
Crossbills are birds of the genus Loxia within the finch family (Fringillidae), with six species. These birds are characterized by the mandibles with crossed tips, which gives the group its English name. Adult males tend to be red or orange in color, and females green or yellow, but there is much variation.
The parrot crossbill is a small passerine bird in the finch family Fringillidae. It breeds in pine forests in northern and northeastern Europe.
The red crossbill or common crossbill is a small passerine bird in the finch family Fringillidae. Crossbills have distinctive mandibles, crossed at the tips, which enable them to extract seeds from conifer cones and other fruits.
The two-barred crossbill or white-winged crossbill is a small passerine bird in the finch family Fringillidae. It breeds in the coniferous forests of North America and the Palearctic.
The Cairngorms are a mountain range in the eastern Highlands of Scotland closely associated with the mountain Cairn Gorm. The Cairngorms became part of Scotland's second national park on 1 September 2003. Although the Cairngorms give their name to, and are at the heart of, the Cairngorms National Park, they only form one part of the national park, alongside other hill ranges such as the Angus Glens and the Monadhliath, and lower areas like Strathspey.
The Caledonian Forest is the ancient (old-growth) temperate forest of Scotland. The forest today is a reduced-extent version of the pre-human-settlement forest, existing in several dozen remnant areas.
Pinus occidentalis, also known as the Hispaniolan pine or Hispaniola pine, is a pine tree endemic to the island of Hispaniola.
Natural history of Scotland concerns the flora, fauna and mycota of Scotland.
Abernethy Forest is a remnant of the Caledonian Forest in Strathspey, in the Highland council area of Scotland. It lies within the Cairngorms National Park, close to the villages of Nethy Bridge, Boat of Garten, and Aviemore. The forest is an RSPB reserve, close to Loch Garten Osprey Centre, which is also owned by the RSPB. It is popular with walkers, as there are various trails throughout the reserve. The forest forms part of the wider Abernethy National Nature Reserve.
The Hispaniolan crossbill is a crossbill that is endemic to the island of Hispaniola, and the only representative of the Loxia genus in the Caribbean.
The thick-billed parrot is a medium-sized parrot endemic to Mexico that formerly ranged into the southwestern United States. Its position in parrot phylogeny is the subject of ongoing discussion; it is sometimes referred to as thick-billed macaw or thick-billed conure. In Mexico, it is locally called guacamaya ("macaw") or cotorra serrana. Classified internationally as Endangered through IUCN, the thick-billed parrot's decline has been central to multiple controversies over wildlife management. In 2018, the estimated wild population in Mexico was 1,700.
The fauna of Scotland is generally typical of the northwest European part of the Palearctic realm, although several of the country's larger mammals were hunted to extinction in historic times and human activity has also led to various species of wildlife being introduced. Scotland's diverse temperate environments support 62 species of wild mammals, including a population of wild cats, important numbers of grey and harbour seals and the most northerly colony of bottlenose dolphins in the world.
The Newfoundland red crossbill is a member of the crossbill genus which has its crossed bill adapted for prying open the tightly closed spruce or pine cones in order to extract the seeds found abundantly on the island of Newfoundland.
The flora of Scotland is an assemblage of native plant species including over 1,600 vascular plants, more than 1,500 lichens and nearly 1,000 bryophytes. The total number of vascular species is low by world standards but lichens and bryophytes are abundant and the latter form a population of global importance. Various populations of rare fern exist, although the impact of 19th-century collectors threatened the existence of several species. The flora is generally typical of the north-west European part of the Palearctic realm and prominent features of the Scottish flora include boreal Caledonian forest, heather moorland and coastal machair. In addition to the native species of vascular plants there are numerous non-native introductions, now believed to make up some 43% of the species in the country.
The flora and fauna of the Outer Hebrides in north west Scotland comprises a unique and diverse ecosystem. A long archipelago, set on the eastern shores of the Atlantic Ocean, it attracts a wide variety of seabirds, and thanks to the Gulf Stream a climate more mild than might be expected at this latitude. Because it is on the Gulf Stream, it also occasionally gets exotic visitors.
The Cassia crossbill is a passerine bird in the family Fringillidae. It is endemic to the South Hills and Albion Mountains in southern Idaho. Cassia crossbill rarely interbreeds with other call types that move into the South Hills of Idaho yearly, and can be considered to represent a distinct species via ecological speciation. The Cassia crossbill have specialized beaks to access the seeds of the lodgepole pine cones in this region, but are poorly adapted to other pine cones in surrounding regions.
Coregonus bavaricus, the Ammersee kilch, is a species of freshwater whitefish endemic to Lake Ammersee in the German state of Upper Bavaria. A small, silver-colored fish, it typically lives between 60–85 m (197–279 ft) deep, though shallower in the summer months. In the early 20th century the Ammersee kilch was an important commercial species, but its population declined drastically in the 1930s onward due to overfishing and eutrophication of the only lake in which it is found. Today it is listed as Critically Endangered by the International Union for Conservation of Nature (IUCN) and may be on the verge of extinction.
Scotland occupies the northern part of the United Kingdom. The landscape is diverse; ranging from rugged mountain terrain to arable flat land with many rivers and lochs.
Glen Tanar is a glen in Aberdeenshire, eastern Scotland, through which the Water of Tanar flows. Near the mouth of the glen, at Tower o' Ess, the Water of Tanar flows into the River Dee. This flows through Deeside into the North Sea at Aberdeen. Glen Tanar contains the third largest area of Caledonian Forest in Scotland, and is of national and European importance. It lies 29 km east from the British royal family's private residence of Balmoral Castle.