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Common Crossbill

 
Animal Encyclopedia: Red crossbill

Loxia curvirostra

SUBFAMILY

Carduelinae

TAXONOMY

Loxia curvirostra Linnaeus, 1758. Six subspecies are recognized.

OTHER COMMON NAMES

English: Common crossbill; French: Bec-croisé des sapins; German: Fichtenkreuzschnabel; Spanish: Piquituerto Común.

PHYSICAL CHARACTERISTICS

The red crossbill has a body length of about 5.5 in (14 cm) and weighs about 1.4 oz (40 g). It has a rather heavy body, a short forked tail, and a stout beak in which the tips of the upper and lower mandibles cross over as an adaptation to extracting seeds from conifer cones. Males are colored overall brick-red, with blackish wings and tail. Females are a dull yellow-brown with darker wings. Juveniles have weakly crossed mandibles, grayolive upperparts and whitish underparts both streaked with dark brown, and a buff-yellow rump.

DISTRIBUTION

The red crossbill is an extremely widespread species that inhabits the boreal and montane forest regions of both North America and Eurasia. It occurs from coast to coast in suitable habitats on both continents. It periodically irrupts from its usual wintering regions and may then be abundant in areas where it is not usually seen.

HABITAT

Red crossbills breed and winter in pine-containing conifer forests of various kinds.

BEHAVIOR

Red crossbills are highly social birds, especially during the non-breeding season when they may occur in large flocks. The territorial song is a repeated series of simple chirps, often given in flight. The male displays to the female by flying above her, vibrating his wings, and delivering an in-flight song.

FEEDING ECOLOGY AND DIET

Red crossbills feed on the seeds of conifers, particularly species of pines. They use their peculiar, crossed bill to force the scales of conifer cones apart and then scoop the seed into their mouths with their tongues. Their diet also includes insects and caterpillars.

REPRODUCTIVE BIOLOGY

Breeding pairs are monogamous and solitary. The female builds a cup-shaped nest of twigs, bark, grass, and rootlets, lined with finer grasses, feathers, fur, hair, and moss. The nest is located on a tree branch far out from the trunk about 6.6–40 ft (2–12 m) above the ground. A clutch of three to four light green or blue eggs spotted with brown and lilac is incubated by the female for 12–18 days. The altricial young are brooded by the female and fed by both parents. They fledge in 15–20 days. Nestlings have straight mandibles that cross gradually after they have been out of the nest for about three weeks. One to two broods per year.

CONSERVATION STATUS

Not threatened. The red crossbill is a widespread and abundant species. Some populations, however, have declined greatly and are considered to be at risk. The subspecies native to the island of Newfoundland, for example, has become extremely rare. Logging operations have destroyed and continue to damage red crossbill habitat.

SIGNIFICANCE TO HUMANS

None known.

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Western Bird Guide: red crossbill
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Loxia curvirostra 5½-6½″ (14-16 cm). Near the size of a House Sparrow, with a heavy head and short tail. Note the crossed mandibles. The sound when it cracks the cones of evergreens often betrays its presence. It acts like a small parrot as it dangles while feeding. Male: Dull red, brighter on the rump; wings and tail blackish. Young males are more orange. Female: Dull olive-gray; yellowish on the rump and underparts. Juvenile: Striped above and below, suggesting a large Pine Siskin; note the bill.

Voice: Note, a hard jip-jip or jip-jip-jip. Song, finch-like warbled passages, jip-jip-jip-jeeaa-jeeaa; trills, chips.

Range: Conifer forests of N. Hemisphere. In N. America, south in mountains to Nicaragua; in East, locally to s. Appalachians. Erratic wanderings in winter.

Habitat: Conifers.


Wikipedia: Common Crossbill
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Common Crossbill
Male Common Crossbill
Female Common Crossbill
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Fringillidae
Genus: Loxia
Species: L. curvirostra
Binomial name
Loxia curvirostra
Linnaeus, 1758

The Common Crossbill (Loxia curvirostra) 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 (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 mandibles crossing at their tips, which gives the group its English name. They are specialist feeders on conifer cones, particularly the various spruce species but also some populations (different species?) in Douglas-fir and various pine species, and the unusual bill shape is an adaptation to assist the extraction of the seeds from the cone.

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, USA, 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.

Common Crossbill diversity

Distinct Eurasian Common Crossbill populations:

  • Balearic Crossbill, Loxia curvirostra balearica
  • North African Crossbill, Loxia c. poliogyna
  • Corsican Crossbill, Loxia c. corsicana
  • Cyprus Crossbill, Loxia c. guillemardi
  • Crimean Crossbill, Loxia c. mariae
  • Luzon Crossbill, Loxia c. luzoniensis
  • Annam Crossbill, Loxia c. meridionalis

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:

  • Altai Crossbill, Loxia c. altaiensis
  • Tien Shan Crossbill, Loxia c. tianschanica
  • Himalayan Crossbill, Loxia c. himalayensis
  • 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 Crossbill (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 Pine Pinus ponderosa scopulorum in the west and in various Pinus species in the east
  • Type 3, corresponds with Loxia c. minor and Loxia c. sitkensis (sitkensis is probably a junior synonym)
  • Type 4, corresponds with Loxia c. neogaea
  • Type 5, corresponds with Loxia c. benti/grinnelli/bendirei
  • Type 6, corresponds with Loxia c. stricklandi
    • Uses Pine species in Section Trifoliae
  • 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
  • Type 9, corresponds with South Hills Crossbill

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:[1];

  • "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")

References

  • BirdLife International (2004). Loxia curvirostra. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 12 May 2006. Database entry includes justification for why this species is of least concern
  • Benkman, Craig W., Smith, Julie W., Keenan, Patrick C., Parchman, Thomas L. and Santisteban, Leonard. "A New Species of the Red Crossbill (Fringillidae: Loxia) From Idaho." The Condor 111(1) (2009): 169-176

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Copyrights:

Animal Encyclopedia. Grzimek's Animal Life Encyclopedia. Copyright © 2005 by The Gale Group, Inc. All rights reserved.  Read more
Western Bird Guide. Peterson Field Guide to Western Birds, by Roger Tory Peterson. Copyright © 1990 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Common Crossbill" Read more