Crossbill
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Crossbill ( Loxia curvirostra ), male |
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| Scientific name | ||||||||||||
| Loxia curvirostra | ||||||||||||
| Linnaeus , 1758 |
The crossbill ( Loxia curvirostra ) is a species of bird from the family of finches (Fringillidae). The crossbill species most frequently found in Central Europe is widespread from Western Europe via Eurasia to East Asia as well as in North and Central America . It can also be found in North Africa and on some Mediterranean islands . The classic habitat is represented by coniferous forest areas up to the tree line in the Alps , especially during the breeding season . In Europe the crossbill is a typical representative of the spruce and fir forests . Its diet consists mainly of spruce seeds , but also of other conifers .
description
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features
The crossbill is characterized by a compact shape and is easily recognized by its strong, round head, its thick, curved beak and its short, deeply forked tail. The beak exceeds the height of the beak at the base in length and shows variations in the subspecies. Crossbills have a body length of 15 to 17 centimeters. The body weight is 34 to 40 grams. The wingspan is 27 to 30 centimeters.
The crossbill has a poorly developed sexual dimorphism . Adult males are predominantly reddish to brick-red in color and have a bright red rump . Depending on the food available, the plumage of the male can take on a yellow or orange color in addition to the red. The wings and tail are dark brown. The underside is also drawn in red. Juvenile males can be recognized by their orange to yellowish-green color, which changes to a reddish-yellow color over time. In flight, dark wings without ties can be seen and the rump appears fresh pink. The eyes are small in relation to the shape and are dark brown. Females are olive green in color and have a yellowish rump. Strong brownish longitudinal stripes can be seen on the flanks. Upper and lower beak are crossed with each other.
The young birds are greenish-gray to brownish in color and show strong, blackish stripes on the flanks, but some young males can have different plumage colors. Upper and lower beak are crossed with each other. The hatched nestlings are densely covered with gray down . The throat is bright red and the marginal ridges yellowish in color. The beak is not yet crossed in nestlings. Only after about 45 days are the upper beak and the lower beak crossed over each other so that they independently extract the seeds from the cones with their beak.
The flight of the crossbill is strong and straight. It is initiated by sudden shouts and fluttering in high treetops . Fast wing flaps with closed wings are performed between the gliding phases.
voice
Crossbills manifest as Stimmfühlungsruf a hard "gip gip gip", also as "klip-klip-klip" sound. It often sounds during the flight. He also lets out calls that sound more like “ö” or “ü”, “tjök” or “tjük”.
The varied singing contains elements that are similar to the flight calls, but also nasal sounds and hard purrs like “kick”. The creaking and scraping sounds can also be heard in all seasons. Sometimes trills and chirps are not loud, but are performed somewhat hesitantly. There are certain similarities to the song of the greenfinch .
The singing is often performed in a convivial manner in larger or smaller groups, which often play around with pine cones at the same time.
Similar species
The crossbill is similar in size and appearance to the parrot crossbill , the Scottish crossbill , the two-barred crossbill and the grosbeak . The crossbill is slightly smaller and has a more intense reddish color. The pine crossbill is characterized by a larger head and thicker beak. The strong beak is not only curved higher at the root, but also at the tip, which makes it appear shorter. The jaw muscles and head are stronger than those of the crossbill. The lure calls are louder and sound deeper like “gob”, “zok”, “kop” or “göpp”. The same distinguishing features apply to the Scottish pine crossbill. The crossbill shows two conspicuous wing bands and umbrella feathers with white tips. It is smaller than the crossbill and its beak is more elongated. Its mating calls are softer and less metallic than those of the crossbill and sound like “giff” or “phiht”. The crossbill differs from the grosbeak mainly in the lack of a light band on the wings and tail.
distribution and habitat
The crossbill is widespread from Western Europe ( Portugal , Spain , France and Great Britain ) via Eurasia to East Asia as well as in North and Central America . It can also be found in North Africa and on some Mediterranean islands . Some parts of the breeding area in the northern hemisphere are only visited occasionally ( invasions ).
The classic habitat is represented by coniferous forest areas up to the tree line in the Alps , especially during the breeding season . In Europe , it is a typical representative of the spruce and fir forests . Although it prefers mountain landscapes , especially in the southern distribution area , it also lives sporadically in spruce forests in the lowlands. Furthermore, the crossbill can also be found in mixed forests , in parks and in large gardens with isolated conifers .
hikes
The appearance of the crossbill is often irregular and somewhat inconsistent. Even in areas where it regularly lives, there are strong fluctuations in the population. These usually run parallel to the supply of spruce seeds, since individual years of particularly high seed production (fattening years) usually lie between several years of lower supply (shortage years). However, the good seed years often do not coincide in different areas, so that in some cases the breeding sites or residence areas trigger either emigration or immigration, depending on what is available in different areas.
In addition, strong invasions occur over large areas , which allow crossbills to migrate to areas that are not regularly visited or, at most, more frequently visited areas. The invasions often, but not always, coincide exactly with the years of shortage. On the contrary, migrations often begin before the size of the new harvest can be seen. It is assumed that a high population density can stimulate or even trigger migration in order to prevent overpopulation of the areas. In addition, some specimens return to their traditional breeding grounds in the second year after the invasion at the earliest.
In years of good cone fattening, large numbers of northern and eastern populations fly into Central Europe. When there is a lack of food, groups often migrate to the same areas along known migration routes. The train moves mostly in a southwesterly direction so that it can reach Spain or even North Africa. The Scandinavian populations moving to England are an exception . The incursions of the Nordic crossbills usually take place from June to August, but birds can usually be observed on the migration from April to December. Many of the roaming birds do not come from the Nordic breeding areas, but are native populations looking for more favorable conditions.
Food and subsistence
The food consists mainly of seeds of spruce , but also from other conifers together. This includes in particular the seeds of fir , pine , larch and birch . The crossbill also eats leaf and flower buds , needles , fruits and berries . During the summer half of the year, food is supplemented by small insects such as aphids (Aphidoidea), butterfly caterpillars and arachnids (arachnids). When hunting insects, the crossbill itself opens the galls on coniferous and deciduous trees .
The crossbill behaves very quietly when eating. It turns its beak around in the branches as a third grasping organ. He holds on to larger cones and tears off smaller ones to hold them with his toes. The scales are spread with crossed beak tips in order to get to the seeds. Depending on whether the tip of the lower jaw is bent to the left or right, the crossbill has to bring its head into a certain position in relation to the pin, so that the jaw and neck muscles develop unevenly through these constant one-sided movements . Tightly closed, immature cones are extremely rarely opened. The consumption of oil-containing seeds leads to an increased need to drink. To satisfy this, leaves and branches are freed from frost or snow is taken up in winter . The Red Crossbill takes in soil or snow soaked in urine to meet its mineral requirements .
Insects and conifer seeds are used as nestling food. According to calculations, one brood consumes around 85,000 seeds by the time it flies out.
Breeding biology
The crossbill becomes sexually mature in the breeding period following hatching. As a rule, a monogamous brood marriage is conducted, but in individual cases bigyny , i.e. the mating of a male with two females, has been proven. The duration and location of the breeding season varies from year to year and depends on the weather and the food spectrum. The breeding season for Central European birds extends from December to May. In favorable years there can be two annual broods.
The crossbill prefers breeding habitats in which there is a sufficiently large food supply. The groups begin to breed together and almost simultaneously with two to five pairs so that only a minimal amount of territorial behavior is shown by claiming a small area around the nest. Later the young birds of the first brood help the adults with feeding the nestlings from the second brood.
Courtship and pairing
At the beginning and during the breeding season, the male performs courtship flights and sings his violent song. During courtship it ruffles its plumage so that it resembles a ball. When a female answers, she continues her singing intensely and can take a feather or a stalk in her beak. After both of them have repeated their singing together several times, the female crouches down to allow the male to mate her. The copulations are often repeated and take place both on the nest, near the nest or further away. In addition, the female can often be fed by the male with drooping and trembling wings (tenderness feeding).
Nesting site selection and nest building
The relatively high nesting site is determined by the female. It is usually found in conifers on a horizontal branch under dense twigs between 4 and 30 meters high. The nest is made by the female alone, with the male accompanying it in the search for material.
The nest is laid out in the trees in such a way that it offers good cover against sight and snow through overhanging branches . The small nest is built from twigs , grass , bark shavings and moss . The inside is padded with grass, lichen , feathers and hair . Depending on the weather, it is padded thinner or thicker with raffia , hair and feathers. The winter nest is built denser and stronger than the summer nest. The materials and construction of the nests are adapted to the season and the climate.
Egg laying and brood care
Eggs are laid daily. The clutch size is two to four eggs , rarely five eggs. These have a greenish or bluish-white basic color with brown or purple-colored spots. Those are often speckled and can be found especially on the blunt pole. In cold weather, the first egg is immediately covered and incubated, even if the temperature is minus 35 degrees Celsius .
The female incubates alone for 14 to 16 days, but is taken care of by the male through regurgitation (recovery of food) and only leaves the nest to defecate .
Development of the young birds
After the asynchronous hatching, the young birds are fledged by the female for 14 to 16 days . During this time they are also fed insects by the female , which receives the food from the male from the crop . After 16 days, both adult birds take over feeding at the nest together. Even when the temperature is below zero, the young birds can be alone for a long time because the adults are looking for food. As a result, they are often found in a constrained state ( torpidity ) by the adult birds, but are active again after a few minutes of huddling. After the keels have broken open , there is seldom huddling and the nest is no longer kept clean, so that the young birds deposit their excrement on the edge of the nest. Due to the dependence on the length of the day and the frequency of feeding, the nestling period can be 16 to 25 days. After the flight, both parents feed the young together for about eight days until they are finally cared for by the male alone because the female takes care of the second brood. After five to eight weeks, the boys are independent.
The crossbill can reach an age of around two to five years in nature under favorable circumstances. In captivity, however, it can live up to 15 years.
behavior
The crossbill is diurnal and not very territorial. So he defends the nest area, but not a territory . It behaves very inconspicuously in all seasons, as it seeks protection in tall conifers.
At all times of the year, with the exception of moulting , the behavior of pair formation and courtship takes place. During the breeding season, couples and families stay in small groups. For the rest of the year, crossbills join together to form smaller or larger groups, which disintegrate again when the food supply dwindles and unite to form new groups in other areas. Mostly the proportion of males corresponds to that of females. It is common for the crossbill to mix in schools with the three other crossbill species .
Inventory and inventory development
The large worldwide distribution area of the crossbill is estimated by the IUCN at 24,400,000 km². The large global population includes around 30,000,000 to 100,000,000 individuals. Since the population is very large and there is a stable trend, the species is classified as not endangered (LC).
The European breeding population accounts for less than a quarter of the global distribution. It is very large with more than 5,800,000 pairs and was stable between 1970 and 1990. Although there were fluctuations between 1990 and 2000, the vast majority of national populations, including key populations in Russia and Fennos Scandinavia , remained largely stable. Since the population as a whole is stable, the crossbill is consequently classified as secure.
Systematics
External system
The phylogeny is true based on the information from data from both studies of the proteins and the morphology of data obtained in agreement that the Stieglitz-like in an older group consisting of Coccothraustes , Pinicola , Leucosticte and Carpodacus , and a younger tribe, consisting of Loxia and Carduelis , must be divided. Allelomorphic and mitochondrial studies of the genes showed that the crossbill and the siskin are so closely related that in 1984 a hybrid between the two species was discovered and proven.
Internal system
18 subspecies are recognized by ITIS:
- Loxia curvirostra curvirostra Linnaeus , 1758 is the nominate form .
- Loxia c. altaiensis Sushkin , 1925
- Loxia c. balearica Homeyer , 1862
- Loxia c. bendirei Ridgway , 1884
- Loxia c. Corsicana Tschusi , 1912
- Loxia c. grinnelli Griscom , 1937
- Loxia c. guillemardi Madarász , 1903
- Loxia c. himalayensis Blyth , 1845
- Loxia c. japonica Ridgway , 1884
- Loxia c. luzoniensis Ogilvie-Grant , 1894
- Loxia c. meridionalis Robinson & Kloss , 1919
- Loxia c. mesamericana Griscom , 1937
- Loxia c. minor Brehm, CL , 1846
- Loxia c. poliogyna Whitaker , 1898
- Loxia c. pusilla Gloger , 1834
- Loxia c. reai Phillips, AR , 1981
- Loxia c. Stricklandi Ridgway , 1885
- Loxia c. vividior Phillips, AR , 1981
Avibase assumes 21 subspecies for Loxia curvirosta . In addition to the subspecies already mentioned, the following three additional subspecies are listed here:
- Loxia curvirostra benti Griscom , 1937
- Loxia curvirostra sitkensis Grinnell , 1909
- Loxia curvirostra tianschanica Laubmann , 1927
However, Loxia curvirostra sensu-lato is divided into two types, namely Loxia curvirostra with the above-mentioned 21 subspecies and Loxia sinesciuris .
Since August 2006 Loxia (c.) Scotia is no longer seen as a subspecies , but has been recognized as an independent species with specific characteristics. The species is limited in its distribution to the Scottish occurrences of the Caledonian Forest , a form of the boreal coniferous forest .
Crossbill and human
designation
Carl von Linné gave the bird the Latin name Loxia curvirostra . Crossbills are also known by many other names. It is called the "Christian bird" because it can often be seen at Christmas and plays an important role in a Christian legend . As a "gout bird", healing powers are attributed to it. It is popularly known as the "gypsy bird" due to its love of hiking. Already by Sachs and Gessner , crossbills were called "Krumbschnabel" or "Chrüzschnabl". Other popular terms are derived from the close connection to conifers: Scots crossbill or Scots parrot.
Mythology and cult
The crossbill was the national bird of the rural Tyrolean people. As the only bird that broods in winter, it was held in high esteem there. For this reason, specimens that hatch in the Advent and Christmas season and have red and not gray plumage as nestlings are given the name "Christmas birds". According to the tradition of the peasant bird scholars, from birth these birds can have not just one or two, but three types of song. Therefore this popular winter bird was caught with preference and kept as a housebird.
The crossbill also plays a role in the legends of Christ , which JN Vogl , Plönnies , Rückert and Julius Mosen dealt with: when Jesus hung on the cross in fear and anxiety in the bitterest pain, a compassionate bird flew over and pulled the nail with all its weak strength who kept his wrist pierced. The dripping blood streamed over the small chest, and his beak arched with the strain. In gratitude, Jesus blessed the good-hearted bird and gave it the blood-red plumage and the cross-shape of the beak as an eternal symbol of his noble deed.
"And the Savior says mildly: Be blessed for and for '
Wear' this sign of this hour forever, blood and cross ornament."
Since then, the crooked beak has been associated with blessings as the “Christ bird” . The house that owns him is said to be consecrated and immune to any spell of wicked people and witches , and the water from which he drinks is said to be beneficial against gout . Since it was said that he would take on all the illnesses of his roommates and housemates, while he would have to suffer death for those who had recovered, people kept him mainly in nurseries. In Vorarlberg those who had had an accident and who had to do without spiritual help believed that it was enough for them to confess their sins to this holy bird.
Even in ancient times , the crossbill was probably a sacred animal, even if only a few traces of it have survived. The people revered him as a means of protection against lightning , so that, like the robin, he was once sacred to the red-bearded storm god Donar . In addition to the red color of its plumage, the peculiar formation of its beak, which is reminiscent of Donar's hammer, can be an indication of this.
The reason for some superstition was given by the fact that dead crossbills hardly decompose or only after a long time because of their high resin content . In various mountainous regions of Germany , the following superstition used to apply: "If the lower beak points to the left, it gives badly, but if it points to the right, luck brings it."
Keeping as an aviary bird
The crossbill was kept as a cage bird by early ornithologists such as Sachs and Gessner due to its peculiarity . The keeping took place in a close bird house. Sometimes he was allowed to fly free. To this day it is kept as an aviary bird. However, wild caught are illegal according to § 20d of the Federal Nature Conservation Act.
literature
- Einhard Bezzel : FSVO manual birds. BLV Buchverlag GmbH & Co. KG, Munich, 2006, ISBN 3-8354-0022-3 .
- Einhard Bezzel: Compendium of the birds of Central Europe. Songbirds. Wiesbaden, 1993.
- Classen / Massoth: Handbook for Carduelids II. Pforzheim, 1994.
- Urs N. Glutz von Blotzheim : Handbook of the birds of Central Europe 14/2, Passeriformes. Aula Verlag, Wiesbaden, 1997, ISBN 3-89104-610-3 .
- Hans Münch: The crossbills. Neue Brehm Bücherei, Westarp Sciences, Aula Verlag, ISBN 3-89432-442-2 .
- Roger Peterson, Guy Montfort, FAD Hollom: The Birds of Europe. Paul Parey Verlag, Hamburg and Berlin, 9th edition 1966, ISBN 3-490-05518-7 .
- Hans E. Wolters: The bird species of the earth. Berlin, 1975–1982.
- W. Wüst: The breeding birds of Central Europe. Munich, 1979.
Web links
- Videos, photos and sound recordings for Loxia curvirostra in the Internet Bird Collection
- Entry at the Swiss Ornithological Institute
- Loxia curvirostra in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed on December 23 of 2008.
- Age and gender characteristics (PDF; 3.7 MB) by Javier Blasco-Zumeta and Gerd-Michael Heinze (English)
- Feathers of the crossbill
Individual evidence
- ↑ a b c d e Hans Münch: The crossbills. Neue Brehm Bücherei, Westarp Sciences, Aula Verlag, ISBN 3-89432-442-2
- ↑ a b c d Urs N. Glutz von Blotzheim: Handbook of the birds of Central Europe 14/2, Passeriformes. Aula Verlag, Wiesbaden, 1997, ISBN 3-89104-610-3
- ↑ Birdlife Factsheet: Red Crossbill
- ^ Birds in Europe: Red Crossbill
- ^ DA Tallman, RL Zusi: A hybrid Red Crossbill-Pine Siskin (Loxia curvirostra & Carduelis pinus) and speculations on the evolution of Loxia. The Auk. Volume 101, pp. 155-158, 1984
- ^ Jill A. Martens, Ned K. Johnson, Genetic Relationships of North American Cardueline Finches. The Cooper Ornithological Society. The Condor. Volume 88, pp. 409–420, 1986 (PDF; 1.1 MB)
- ↑ ITIS Report: Loxia curvirostra (Linnaeus, 1758)
- ↑ Avibase Database: Crossbill (Loxia curvirostra) (Linnaeus, 1758)
- ↑ Avibase Database: Red Crossbill (Loxia curvirostra) (Linnaeus, 1758)
- ↑ South Hills Crossbill ( Loxia sinesciuris ) at Avibase
- ↑ RPSB Scotland: Status of 'UK's only endemic bird species' confirmed
- ↑ BBC Scotland: Accent 'confirms unique species
- ↑ Avibase Database: Crossbill (Loxia curvirostra) (Linnaeus, 1758) - split
- ↑ a b c d Dr. Ludwig von Hörmann: The Christmas bird. Tiroler Heimatblätter, 15th year, issue 12, 1937, pp. 386–388, web link
- ↑ Claus-Peter Lieckfeld , Veronika Straaß : Mythos Vogel. History, legends, 40 bird portraits. BLV Verlag, 2002