Common Crossbill
Encyclopedia
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 (possibly different species) breed in pine
forests in certain areas of all three continents, and in North America, also in Douglas-fir
. It nests in conifers
, laying 3–5 eggs.
This crossbill
is mainly resident, but will regularly irrupt
south if its food source fails. This species will form flocks outside the breeding season, often mixed with other crossbills.
The crossbills are characterised by the mandible
s crossing at their tips, which gives the group its English name. They are specialist feeders on conifer cone
s, particularly the various spruce species, and the unusual bill shape is an adaptation to assist the extraction of the seeds from the cone. Some populations, which may be different species, also feed on Douglas-fir and various pine species.
Adult males tend to be red or orange in colour, and females green or yellow, but there is much variation.
This species is difficult to separate from Parrot Crossbill
and Scottish Crossbill
, both of which breed within its Eurasian range. The identification problem is less severe in North America, where only Red Crossbill and White-winged Crossbill
occur. However, the South Hills Crossbill
, occurring in the South Hills and Albion Mountains in Idaho
has recently been described as a new species (Loxia sinesciuris). It is virtually identical to the Red Crossbill differing slightly in body dimensions and calls and shows a very low degree of hybridization with the Red Crossbill.
Plumage
distinctions from Parrot and Scottish Crossbills are negligible. The head and bill are smaller than in either of the other species. Care is needed to identify this species. The glip or chup call is probably the best indicator.
Work on vocalisation in North America suggest that, in that continent alone, there are eight or nine populations of Red Crossbill with different calls, which rarely if ever interbreed. These forms also vary in terms of bill size and structure, and specialise on the seed cones of different species of conifer. Few ornithologists
seem inclined to give these forms species status at present.
Some large-billed, pine-feeding populations currently assigned to this species in the Mediterranean
area may possibly be better referred to either Parrot Crossbill or alternatively to new species in their own right, but as yet, research into them is still at a very early stage. These include Balearic Crossbill L. curvirostra balearica and North African Crossbill L. curvirostra poliogyna, feeding primarily on Aleppo Pine
(Pinus halepensis); Cyprus Crossbill L. curvirostra guillemardi, feeding primarily on European black pine
(Pinus nigra); and an as-yet unidentified crossbill with a Parrot Crossbill-size bill feeding primarily on Bosnian Pine
(Pinus heldreichii) in the Balkans
. These populations also differ on plumage, with the Balearic, North African and Cyprus races having yellower males, and the Balkan type having deep purple-pink males; this however merely reflects the differing anthocyanin
content of the cones they feed on, as these pigments are transferred to the feathers.
As with Parrot and Scottish Crossbills, all of the above are fairly sedentary forms associated with hard-coned Pinus species. The following are more associated with the softer cones of spruce
and larch
:
North American Red Crossbill subspecies list based on biometrics:
Jeff Groth's classification of North American Red Crossbill forms based on call-types:
Summers' list of European Common Crossbill forms (with Parrot & Scottish) based on Flight/Excitement calls:
"The Sound Approach's" classification of European Common Crossbill types based on call-types:;
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 breeds in the spruce
Spruce
A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
forests of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, where it is known as Red Crossbill, as well as Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
; some populations (possibly different species) breed 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:...
forests in certain areas of all three continents, and in North America, also in Douglas-fir
Douglas-fir
Douglas-fir is one of the English common names for evergreen coniferous trees of the genus Pseudotsuga in the family Pinaceae. Other common names include Douglas tree, and Oregon pine. There are five species, two in western North America, one in Mexico, and two in eastern Asia...
. It nests in conifers
Pinophyta
The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being...
, laying 3–5 eggs.
This 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...
is mainly resident, but will regularly irrupt
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...
south if its food source fails. This species will form flocks outside the breeding season, often mixed with other crossbills.
The crossbills are characterised by the mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
s crossing at their tips, which gives the group its English 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, particularly the various spruce species, and the unusual bill shape is an adaptation to assist the extraction of the seeds from the cone. Some populations, which may be different species, also feed on Douglas-fir and various pine species.
Adult males tend to be red or orange in colour, and females green or yellow, but there is much variation.
This species is difficult to separate from 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...
and Scottish Crossbill
Scottish Crossbill
The Scottish Crossbill is a small passerine bird in the finch family Fringillidae. It is endemic to the Caledonian Forests of Scotland, and is the only vertebrate unique to the United Kingdom...
, both of which breed within its Eurasian range. The identification problem is less severe in North America, where only Red Crossbill and White-winged Crossbill
Two-barred Crossbill
The Two-barred Crossbill , known as the White-winged Crossbill in North America, is a small passerine bird in the finch family Fringillidae...
occur. However, the South Hills Crossbill
South Hills Crossbill
The South Hills Crossbill is a passerine bird in the family Fringillidae. It's endemic to the South Hills and Albion Mountains in southern Idaho...
, occurring in the South Hills and Albion Mountains in Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
has recently been described as a new species (Loxia sinesciuris). It is virtually identical to the Red Crossbill differing slightly in body dimensions and calls and shows a very low degree of hybridization with the Red Crossbill.
Plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
distinctions from Parrot and Scottish Crossbills are negligible. The head and bill are smaller than in either of the other species. Care is needed to identify this species. The glip or chup call is probably the best indicator.
Work on vocalisation in North America suggest that, in that continent alone, there are eight or nine populations of Red Crossbill with different calls, which rarely if ever interbreed. These forms also vary in terms of bill size and structure, and specialise on the seed cones of different species of conifer. Few ornithologists
Ornithology
Ornithology is a branch of zoology that concerns the study of birds. Several aspects of ornithology differ from related disciplines, due partly to the high visibility and the aesthetic appeal of birds...
seem inclined to give these forms species status at present.
Some large-billed, pine-feeding populations currently assigned to this species in the Mediterranean
Mediterranean Basin
In biogeography, the Mediterranean Basin refers to the lands around the Mediterranean Sea that have a Mediterranean climate, with mild, rainy winters and hot, dry summers, which supports characteristic Mediterranean forests, woodlands, and scrub vegetation...
area may possibly be better referred to either Parrot Crossbill or alternatively to new species in their own right, but as yet, research into them is still at a very early stage. These include Balearic Crossbill L. curvirostra balearica and North African Crossbill L. curvirostra poliogyna, feeding primarily on Aleppo Pine
Aleppo Pine
Pinus halepensis, commonly known as the Aleppo Pine, is a pine native to the Mediterranean region. Their range extends from Morocco and Spain north to southern France, Italy and Croatia, and east to Greece and northern Tunisia, and Libya, with an outlying population in Syria, Lebanon, southern...
(Pinus halepensis); Cyprus Crossbill L. curvirostra guillemardi, feeding primarily on European black pine
European Black Pine
Pinus nigra, the European Black Pine, is a moderately variable species of pine, occurring across southern Mediterranean Europe from Spain to the Crimea, in Asia Minor and on Cyprus, and in the high mountains of the Maghreb in North Africa....
(Pinus nigra); and an as-yet unidentified crossbill with a Parrot Crossbill-size bill feeding primarily on Bosnian Pine
Bosnian Pine
The Bosnian Pine is a species of pine native to Bosnia but is also found in the mountains of southeastern Europe, in southwestern Bulgaria, Bosnia, Albania, the Republic of Macedonia, Serbia, northern Greece , and locally in southern Italy ,...
(Pinus heldreichii) in the Balkans
Balkans
The Balkans is a geopolitical and cultural region of southeastern Europe...
. These populations also differ on plumage, with the Balearic, North African and Cyprus races having yellower males, and the Balkan type having deep purple-pink males; this however merely reflects the differing anthocyanin
Anthocyanin
Anthocyanins are water-soluble vacuolar pigments that may appear red, purple, or blue according to pH...
content of the cones they feed on, as these pigments are transferred to the feathers.
Diversity
Distinct Eurasian Common Crossbill populations:- Balearic Crossbill, Loxia curvirostra balearica
- Associated with Aleppo PineAleppo PinePinus halepensis, commonly known as the Aleppo Pine, is a pine native to the Mediterranean region. Their range extends from Morocco and Spain north to southern France, Italy and Croatia, and east to Greece and northern Tunisia, and Libya, with an outlying population in Syria, Lebanon, southern...
Pinus halepensis
- Associated with Aleppo Pine
- North African Crossbill, Loxia c. poliogyna
- Associated with Aleppo PineAleppo PinePinus halepensis, commonly known as the Aleppo Pine, is a pine native to the Mediterranean region. Their range extends from Morocco and Spain north to southern France, Italy and Croatia, and east to Greece and northern Tunisia, and Libya, with an outlying population in Syria, Lebanon, southern...
Pinus halepensis
- Associated with Aleppo Pine
- Corsican Crossbill, Loxia c. corsicana
- Associated with European Black PineEuropean Black PinePinus nigra, the European Black Pine, is a moderately variable species of pine, occurring across southern Mediterranean Europe from Spain to the Crimea, in Asia Minor and on Cyprus, and in the high mountains of the Maghreb in North Africa....
, Pinus nigra
- Associated with European Black Pine
- Cyprus Crossbill, Loxia c. guillemardi
- Associated with European Black PineEuropean Black PinePinus nigra, the European Black Pine, is a moderately variable species of pine, occurring across southern Mediterranean Europe from Spain to the Crimea, in Asia Minor and on Cyprus, and in the high mountains of the Maghreb in North Africa....
, Pinus nigra
- Associated with European Black Pine
- Crimean Crossbill, Loxia c. mariae
- Associated with European Black PineEuropean Black PinePinus nigra, the European Black Pine, is a moderately variable species of pine, occurring across southern Mediterranean Europe from Spain to the Crimea, in Asia Minor and on Cyprus, and in the high mountains of the Maghreb in North Africa....
, Pinus nigra?
- Associated with European Black Pine
- Luzon Crossbill, Loxia c. luzoniensis
- Associated with Khasi PineKhasi PineThe Khasi Pine, Pinus kesiya, is one of the most distributed pines in Asia. Its range extends south and east from the Khasi hills in the northeast Indian state of Meghalaya from where it got its name to northern Thailand, Burma, Laos, southernmost China, Vietnam and the Philippines...
, Pinus kesiya
- Associated with Khasi Pine
- Annam Crossbill, Loxia c. meridionalis
- Associated with Khasi PineKhasi PineThe Khasi Pine, Pinus kesiya, is one of the most distributed pines in Asia. Its range extends south and east from the Khasi hills in the northeast Indian state of Meghalaya from where it got its name to northern Thailand, Burma, Laos, southernmost China, Vietnam and the Philippines...
, Pinus kesiya
- Associated with Khasi Pine
As with Parrot and Scottish Crossbills, all of the above are fairly sedentary forms associated with hard-coned Pinus species. The following are more associated with the softer cones of spruce
Spruce
A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
and 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...
:
- Altai Crossbill, Loxia c. altaiensis
- Associated with spruceSpruceA spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
s
- Associated with spruce
- Tien Shan Crossbill, Loxia c. tianschanica
- Associated with Schrenk's SpruceSchrenk's SpruceSchrenk's Spruce, Picea schrenkiana, is a spruce native to the Tian Shan mountains of central Asia in western China , Kazakhstan, Kyrgyzstan and Northern Pakistan. It grows at altitudes of 1,300-3,600 metres, usually in pure forests, sometimes mixed with the Tien Shan variety of Siberian Fir...
Picea shrenkiana
- Associated with Schrenk's Spruce
- Himalayan Crossbill, Loxia c. himalayensis
- Associated with Himalayan Hemlock Tsuga dumosa
- Japanese Crossbill, Loxia c. japonica
North American Red Crossbill subspecies list based on biometrics:
- Newfoundland Crossbill, Loxia c. percna Possibly extinct
- Lesser Crossbill, Loxia c. minor
- Sitka Crossbill, Loxia c. sitkensis
- Loxia c. neogaea
- Rocky Mountain Crossbill, Loxia c. benti
- Sierra Crossbill, Loxia c. grinnelli
- Bendire Crossbill, Loxia c. bendirei
- Mexican Crossbill, Loxia c. stricklandi
- Central American Crossbill, Loxia c. mesamericana
- South Hills CrossbillSouth Hills CrossbillThe South Hills Crossbill is a passerine bird in the family Fringillidae. It's endemic to the South Hills and Albion Mountains in southern Idaho...
(described as new species (Loxia sinesciuris) in 2009)
Jeff Groth's classification of North American Red Crossbill forms based on call-types:
- Type 1, corresponds with Loxia c. neogaea
- Recorded on Tsuga species, Picea glauca, Pinus strobus
- Type 2, corresponds with Loxia c. benti/grinnelli/bendirei
- Recorded on Rocky Mountains Ponderosa PinePonderosa PinePinus ponderosa, commonly known as the Ponderosa Pine, Bull Pine, Blackjack Pine, or Western Yellow Pine, is a widespread and variable pine native to western North America. It was first described by David Douglas in 1826, from eastern Washington near present-day Spokane...
Pinus ponderosa scopulorum in the west and in various Pinus species in the east
- Recorded on Rocky Mountains Ponderosa Pine
- Type 3, corresponds with Loxia c. minor and Loxia c. sitkensis (sitkensis is probably a junior synonymSynonymSynonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...
)- Recorded on Western HemlockWestern HemlockTsuga heterophylla. the Western Hemlock, is a species of hemlock native to the west coast of North America, with its northwestern limit on the Kenai Peninsula, Alaska, and its southeastern limit in northern Sonoma County, California.-Habitat:...
Tsuga heterophylla
- Recorded on Western Hemlock
- Type 4, corresponds with Loxia c. neogaea
- Recorded on Douglas Fir Pseudotsuga menziesii
- Type 5, corresponds with Loxia c. benti/grinnelli/bendirei
- Recorded on Lodgepole PineLodgepole PineLodgepole 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 latifolia
- Recorded on Lodgepole Pine
- Type 6, corresponds with Loxia c. stricklandi
- Uses PinePinePines 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:...
species in Section Trifoliae
- Uses Pine
- Type 7, corresponds with Loxia c. benti/grinnelli/bendirei
- In terms of diet this type is possibly a generalist
- Type 8, corresponds with Loxia c. percna
- Uses Black SpruceBlack SprucePicea mariana is a species of spruce native to northern North America, from Newfoundland west to Alaska, and south to northern New York, Minnesota and central British Columbia...
Picea mariana
- Uses Black Spruce
- Type 9, corresponds with South Hills CrossbillSouth Hills CrossbillThe South Hills Crossbill is a passerine bird in the family Fringillidae. It's endemic to the South Hills and Albion Mountains in southern Idaho...
- Isolated population of Lodgepole PineLodgepole PineLodgepole 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 latifolia
- Isolated population of Lodgepole Pine
Summers' list of European Common Crossbill forms (with Parrot & Scottish) based on Flight/Excitement calls:
- 1A, corresponds with "British" Crossbill
- 1B, corresponds with "Parakeet" Crossbill
- 2B, corresponds with "Wandering" Crossbill
- 2D, corresponds with Parrot Crossbill Loxia pytyopsittacus
- 3C, corresponds with Scottish Crossbill Loxia scotica
- 3D, corresponds with Balearic Crossbill
- 3E, corresponds with North African Crossbill
- 4E, corresponds with "Glip" Crossbill
- 5D, corresponds with Cyprus Crossbill
"The Sound Approach's" classification of European Common Crossbill types based on call-types:;
- "Wandering" Crossbill (Type A - flight call "Keep")
- "Bohemian" Crossbill (Type B - flight call "Weet")
- "Glip" Crossbill (Type C - flight call "Glip")
- "Phantom" Crossbill (Type D - flight call "Jip")
- "British" Crossbill (Type E - flight call "Chip")
- "Scarce" Crossbill (Type F - flight call "Trip")
- "Parakeet" Crossbill (Type X - flight call "Cheep")