Scottish Crossbill
Encyclopedia
The Scottish Crossbill is a small passerine
bird
in the finch
family Fringillidae. It is endemic to the Caledonian Forest
s of Scotland
, and is the only vertebrate
unique to the United Kingdom
. The Scottish Crossbill was confirmed as a unique species
in August 2006, on the basis of having a distinctive bird song
.
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 crossbill
s - some even stated they have "Scottish accents
".
Research in Scotland has shown that Common, Parrot and Scottish crossbills are reproductively isolated, and the diagnostic calls and bill dimensions have not been lost. They are therefore good species.
The population is thought to be less than 2000 birds. It nests in pine
s or other conifers, laying 2-5 egg
s.
The Scottish Crossbill breeds in the native Scots pine
(Pinus sylvestris), Caledonian forests of the Scottish Highlands
, but (perhaps surprisingly), often also in forestry
plantation
s 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 cone
s, 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 Common 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.
, 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 they only attract and pair with potential mates of the same race.
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.
programmes for the race.
In future years, Scottish Crossbills could suffer from the effects of global warming
.
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
in the finch
Finch
The true finches are passerine birds in the family Fringillidae. They are predominantly seed-eating songbirds. Most are native to the Northern Hemisphere, but one subfamily is endemic to the Neotropics, one to the Hawaiian Islands, and one subfamily – monotypic at genus level – is found...
family Fringillidae. It is endemic to the Caledonian Forest
Caledonian Forest
The Caledonian Forest is the name of a type of woodland that once covered vast areas of Scotland. Today, however, only 1% of the original forest survives, covering in 84 locations. The forests are home to a wide variety of wildlife, much of which is not found elsewhere in the British...
s of Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
, and is the only vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
unique to the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
. The Scottish Crossbill was confirmed as a unique species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in August 2006, on the basis of having a distinctive bird song
Bird song
Bird vocalization includes both bird calls and bird songs. In non-technical use, bird songs are the bird sounds that are melodious to the human ear. In ornithology and birding, songs are distinguished by function from calls.-Definition:The distinction between songs and calls is based upon...
.
History and current status
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 Common CrossbillCommon Crossbill
The Common Crossbill is a small passerine bird in the finch family Fringillidae. It breeds in the spruce forests of North America, where it is known as Red Crossbill, as well as Europe and Asia; some populations breed in pine forests in certain areas of all three continents, and in North...
or the Parrot Crossbill
Parrot Crossbill
The Parrot Crossbill is a small passerine bird in the finch family Fringillidae.This bird breeds in the pine forests of northwest Europe and into western Russia...
, both of which also occur in the Caledonian Forest
Caledonian Forest
The Caledonian Forest is the name of a type of woodland that once covered vast areas of Scotland. Today, however, only 1% of the original forest survives, covering in 84 locations. The forests are home to a wide variety of wildlife, much of which is not found elsewhere in the British...
.
RSPB research showed that Scottish Crossbills have quite distinct flight
Bird flight
Flight is the main mode of locomotion used by most of the world's bird species. Flight assists birds while feeding, breeding and avoiding predators....
and excitement calls from other crossbill
Crossbill
The crossbill is a bird in the finch family . The three to five species are all classified in the genus Loxia. These birds are characterised by the mandibles crossing at their tips, which gives the group its English name...
s - some even stated they have "Scottish accents
Scottish English
Scottish English refers to the varieties of English spoken in Scotland. It may or may not be considered distinct from the Scots language. It is always considered distinct from Scottish Gaelic, a Celtic language....
".
Research in Scotland has shown that Common, Parrot and Scottish crossbills are reproductively isolated, and the diagnostic calls and bill dimensions have not been lost. They are therefore good species.
The population is thought to be less than 2000 birds. It nests in pine
Pine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
s or other conifers, laying 2-5 egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
s.
The Scottish Crossbill breeds in the native Scots pine
Scots Pine
Pinus sylvestris, commonly known as the Scots Pine, is a species of pine native to Europe and Asia, ranging from Scotland, Ireland and Portugal in the west, east to eastern Siberia, south to the Caucasus Mountains, and as far north as well inside the Arctic Circle in Scandinavia...
(Pinus sylvestris), Caledonian forests of the Scottish Highlands
Scottish Highlands
The Highlands is an historic region of Scotland. The area is sometimes referred to as the "Scottish Highlands". It was culturally distinguishable from the Lowlands from the later Middle Ages into the modern period, when Lowland Scots replaced Scottish Gaelic throughout most of the Lowlands...
, but (perhaps surprisingly), often also in forestry
Forestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
plantation
Plantation
A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...
s of exotic
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
conifers, notably Larch
Larch
Larches are conifers in the genus Larix, in the family Pinaceae. Growing from 15 to 50m tall, they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains further south...
(Larix decidua and L. kaempferi) and Lodgepole pine
Lodgepole Pine
Lodgepole Pine, Pinus contorta, also known as Shore Pine, is a common tree in western North America. Like all pines, it is evergreen.-Subspecies:...
(Pinus contorta).
This species of crossbill is resident, and is not known to migrate
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
. It will form flocks
Flock (birds)
A flock is a group of birds conducting flocking behavior in flight, or while foraging. The term is akin to the herd amongst mammals. The benefits of aggregating in flocks are varied and flocks will form explicitly for specific purposes...
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
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
name. They are specialist feeders on conifer cone
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
s, 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 Common and Parrot, and plumage
Feather
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...
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
Sonogram
A sonogram may refer to the following:* A diagnostic medical image created using ultrasound echo equipment, see medical ultrasonography...
to confirm the identity.
Bill structure
According to a lengthy scientific study by the RSPB, 'Celtic' crossbills differ in bill size from other crossbill species found in Great BritainGreat Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
, 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 they only attract and pair with potential mates of the same race.
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.
Calls
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 conservationConservation movement
The conservation movement, also known as nature conservation, is a political, environmental and a social movement that seeks to protect natural resources including animal, fungus and plant species as well as their habitat for the future....
programmes for the race.
Conservation
The first survey of Scottish Crossbills is due in 2008.In future years, Scottish Crossbills could suffer from the effects of global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
.
External links
Database entry includes justification for why this species is listed as data deficient- RSPB Species confirmation
- http://www.rspb.org.uk/biodiversity/RSPBandbiodiversity/lead_partner/birds/scottishcrossbill/index.asp BAP report (RSPB site)
- Scottish crossbill identification
- Scottish Crossbill - A to Z of UK Birds
- Species profile: Scottish crossbill Trees for Life
- BBC News Release
- Loxia Fantastica Blog dealing with crossbills in ScotlandScotlandScotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...