Crossbills


Also found in: Dictionary, Thesaurus.

Crossbills

 

birds constituting the genus Loxia of the family Fringillidae. They measure up to 20 cm long and weigh 30–58 g. The upper and lower mandibles are crossed, an adaptation for extracting seeds from cones of spruce, pine, and other conifers. The plumage of the males is reddish and of the females and the young, greenish.

There are three species, all represented in the USSR. The red, or common, crossbill (L. curvirostra) inhabits the coniferous forests of Europe, northwestern Africa, northern Asia, Central Asia, the Philippines, and North and Central America (south as far as Guatemala). The white-winged, or two-barred, crossbill (L. leucoptera) inhabits northern Europe, Asia, and North America. The parrot crossbill (L. pityopsittacus) inhabits the coniferous forests of northern Europe from Scotland to the Urals. Reproductive periods depend on the seed yields of coniferous varieties. In favorable years crossbills may even nest in the winter. The nests, with thick walls and a warm lining of feathers and fur, are built on trees. The three to five eggs that are laid are incubated only by the female. The principal diet is conifer seeds; the seeds of other plants are sometimes eaten and, on occasion, insects.

References in periodicals archive ?
Amazingly, for a small bird (only just bigger than a house sparrow), the crossbill can lay eggs in January.
In the years when there are no cones, there are also no crossbills.
(1957) reported the red crossbill (Loxia curvirostra) in Mexico from northern Baja California, Sinaloa, Nayarit, Jalisco, Michoacan, Guerrero, Chiapas, Chihuahua, Durango, Queretaro, Mexico, Distrito Federal, Morelos, San Luis Potosi, Puebla, Tamaulipas, and Veracruz.
The primary red feather pigment of male crossbills was found in the birds' liver and blood, which implied that that the carotenoids are synthesized in the liver and then travel to the peripheral tissues via the bloodstream.
An RSPB study has proved the Scottish crossbill is the only UK species that does not live anywhere else.
The variety of the bird differs in bill size and call from other UK crossbills.
-A NUMBER of rare Parrot and Two-barred Crossbills have been found among large flocks of Common Crossbills that have invaded Britain from Scandinavia in search of pine cone seeds.
Red crossbills (Loxia curvirostra), Botteri's sparrows (Aimophila botterii) and black-headed siskins (Carduelis notara) were each encountered only once, all in dense vegetation not used by grasshopper sparrows.
Benkman (1996) showed that variation in the rate of mandible crossing direction in Crossbills (Loxia spp.) was a result of frequency-dependent selection.
Fruit and seeds are the main food of mammals like squirrels (Sciurus), chipmunks or burunduks (Tamias), woodmice (Apodemus), and birds, such as the nutcracker (Nucifraga) and crossbills (Loxia).
Benkman (1993) has shown that the diversity of Red Crossbills (Loxia spp.) in northwestern North America can be exp lained by their differential abilities to utilize various conifer species as resources.
The little flock of red crossbills and white-winged crossbills had alighted in a tall Norway spruce at the edge of the parking lot.