Carduelis spinus (*)
Carduelis spinus Linnaeus, 1758
The Eurasian Siskin (Carduelis spinus) is a small passerine bird in the finch family Fringillidae. It is very common throughout Europe and Asia. It is found in forested areas, both coniferous and mixed woodland where it feeds on seeds of all kinds, especially of alder and conifers. It can be distinguished from other similar finches by the color of the plumage. The upper parts are greyish green and the under parts grey-streaked white. Its wings are black with a conspicuous yellow wing bar, and the tail is black with yellow sides. The male has a mainly yellow face and breast, with a neat black cap. Female and young birds have a greyish green head and no cap. It is a trusting, sociable and active bird. The song of this bird is a pleasant mix of twitters and trills. For these reasons it is often raised in captivity.
These birds have an unusual migration pattern as every few years in winter they migrate southwards in large numbers. The reasons for this behavior are not known but may be related to climatic factors and above all the availability of food. In this way overwintering populations can thrive where food is abundant.
This small finch is an acrobatic feeder, often hanging upside-down like a tit. It will visit garden bird feeding stations.
The Siskin is a small, short-tailed bird, 11–12.5 centimetres (4.3–4.9 in) in length with a wingspan that ranges from 20–23 centimetres (7.9–9.1 in). It weighs between 10–18 grams (0.35–0.63 oz).
The bird's appearance presents a sexual dimorphism. The male has a greyish green back; yellow rump; the sides of the tail are yellow and the end is black; the wings are black with a distinctive yellow wing stripe; its breast is yellowish becoming whiter and striped towards the cloaca; it has a black bib (or chin patch) and on its head it has two yellow auriculas and a black cap. The amount of black on the bid is very variable between males and the size of the bib has been related to dominance within a flock.
The plumage of the female is more olive-colored than the male. The cap and the auriculas are greenish with a white bib and a rump that is a slightly striped whitish yellow.
The young have a similar coloration to the females, with drab colors and a more subdued plumage.
The shape of the Siskin's beak is determined by its feeding habits. It is strong although it is also slender in order to pick up the seeds on which they feed. The legs and feet are dark brown and the eyes are black.
The Siskin is easy to recognize, but in some instances it can be confused with other finches such as the Citril Finch, the Greenfinch or the European Serin.
It has a rapid and bounding flight pattern that is similar to other finches.
Song and call
This bird has two calls, both powerful but conflicting, one is descending and the other is ascending, their onomatopoeic sounds can be represented as "tilu" and "tluih". On occasions they also issue a harsh rattling chirrup.
The song is similar to the other finches, a smooth and rapid twitter and trill with a long duration and which is occasionally interrupted by a stronger of shorter syllable. Siskins sing throughout the year and often in groups.
The Siskin was first was described by Linnaeus in 1758 as Fringilla spinus. In 1760, Brisson described the genus Carduelis, where this species would finally be placed.
Despite being found across a wide area it is a monotypic species, that is, there are no distinct subspecies. This could be explained by a number of factors such as:
* A female which has a number of clutches of eggs in one breeding season, each in a different place.
It is a bird that does not remain for long in one area but which varies the areas it used for breeding, feeding, over-wintering from one year to the next.
Its habitat is forested areas at a particular altitude on a mountain side and they have a certain predilection for humid areas. Coniferous woodland, especially Spruce, is favoured for breeding. It builds its nest in a tree, laying 2-6 eggs. The British range of this once local breeder has expanded greatly due to an increase in commercial conifer plantations. The Siskin also breeds in mixed woodland; while in winter they prefer stubble and crops and areas containing trees with seeds.
The worldwide population of the Siskin is estimated as between 20 and 36 million. The European population is estimated as between 2.7 y 15 million pairs. There does not seem to be a specific trend in population numbers and for this reason the IUCN has listed their conservation status as "Least Concern". The Siskin appears in Annex II of the Berne Convention as a protected bird species.
The Siskin is mainly a granivore although it varies its diet depending on the season. It feeds in trees avoiding eating on the ground.
In autumn and winter its diet is based on the seeds of deciduous trees such as birch and above all alder. They also visit cultivated areas and pasture where they join with other finches in eating the seeds of various Compositae such as thistles, dandelions, artemisias, knapweeds and other herbaceous plants such as St John's wort, meadowsweet and sorrel.
In spring, during the breeding season, they are found in coniferous forests. At this time their feeding is based on the seeds of these trees, especially on trees belonging to the genera Abies, Picea and Larix. They also feed on elms and poplars. When feeding the young they eat more insects, mainly beetles, as the proteins they contain help the chicks to grow. In summer their feeding is more varied, adding other herbaceous plants to their diet of conifer seeds: goosefoots and other Compositae.
Pairs are generally formed during the winter period before migration. The males compete aggressively for the females. As part of the courtship the male plumps up the feathers of the pileus and rump, making itself bigger, extending the tail and singing repeatedly.  They also make mating flights from tree to tree, although they are not as eye-catching as the flights of the other finches. They construct a nest that is generally located at the end of a relatively high branch in a conifer, such that the nest is reasonably hidden and difficult to see. On the Spanish Peninsular they make their nests in afirs, Scotch pine and Corsican pine. They form small colonies of up to six pairs with the nests located near to each other. The nest is small and bowl-shaped. It is made from small twigs, dried grasses, moss and lichen and lined with down. The first brood is born in mid-April. The female lays between 2 and 6 eggs. The eggs are white or light grey or light blue, with small brown spots and they are approximately 16.5mm by 12mm in size.
Incubation takes between 10 and 14 days and is carried out entirely by the female. The chicks are altricial and nidicolous. They leave the nest after 15 days in a semi-feathered condition. They then remain close to the nest area for up to a month when, with their plumage now complete, they disperse. The Siskin usually has a second brood, from the middle of June up to the middle of July.
Like many of the finches the Siskin is valued by aviculturalists as a domestic species for its song and appearance. They do not require specific care and adapt well to captivity, although they do not breed well in captivity. There are no specific diseases that affect the species, although they can show certain intestinal pathologies associated with a poor diet. They live for between 11 and 14 years, in sharp contrast to the 2 or 3 years it is estimated they live in the wild.
They form hybrids with some other finches (for example canaries) giving rise to intermediate species. Hybridization also occurs in nature without human intervention. In some areas individuals that are found are the result of escapes or releases of captive birds.
* Poland, Gibraltar, Benin and Belgium have all issued postage stamps bearing the image of the Siskin.
* In Saint Petersburg there is a statue of a Siskin, as its colours are the same as the uniform worn by the students at an elite school in the city. These students have come to be known by the sobriquet Siskin, Russian: Чиж. This term was popularized in the Russian children's song Chizhik-Pyzhik.
Carduelis spinus is also called 'European Siskin', 'Common Siskin' or, in Anglophone Europe, is just 'Siskin'. Other (archaic) names include 'Black-headed Goldfinch', 'Barley Bird' and 'Aberdevine'
* Lethaby, Nick (1997) Identification of Pine Siskin Birding World 10(10): 383-6 (covers separation of European Siskin from Pine Siskin C. pinus)
1. ^ BirdLife International (2004). Carduelis spinus. 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
Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License