Pine siskin (Carduelis pinus)
|Size||Length: 11 - 14 cm (2) (3)|
Wingspan: 18 - 22 cm (2)
|Weight||12 - 18 g (2) (3)|
- The pine siskin is able to raise its metabolic rate to keep warm, and can increase it up to 40% higher than other similarly sized birds.
- A specially adapted pouch in the throat of the pine siskin is able to store food weighing up to 10% of its own weight.
- The sharp, pointed bill of the pine siskin helps it when picking and eating the young buds and seeds from trees.
The pine siskin is classified as Least Concern (LC) on the IUCN Red List (1).
The pine siskin (Carduelis pinus) is a very small songbird with brown, heavily streaked upperparts, white or grey underparts and subtle yellow markings on the tips of the tail and wings (2) (3). The tail and wings are otherwise dusky brown or black, apart from two buffy wingbars, which fade to white as the individual ages (3). The tail is short and notched (2), and the yellow markings on the tail and wings are more visible when the bird is in flight (2) (3). The pine siskin’s bill is sharp, pointed and notched and can vary in colour between dusky brown and black (2) (3). The colour of the legs and feet varies between dark brown, red or dark horn, and the eyes of this species are brown (2) (3).
The male and female pine siskin are similar in appearance. The bill of the juvenile is pink-buff and its plumage is mostly buffy-yellow, occasionally with an olive-brown tinge. By autumn, the juvenile pine siskin is similar in appearance to the adult (3).
There are two recognised subspecies of pine siskin, Carduelis pinus macroptera and Carduelis pinus perplexa, which differ in size and colouration (3).
The song of the pine siskin is a long, complex utterance and is mostly made by the male during the breeding season (3). The short, simple call is a harsh ‘zreeeeeeeet’ or an explosive ‘zwee’ or ‘psee’ and is made by both sexes (2).
The range of the pine siskin extends south from southern Alaska and Canada, through the United States to Mexico (3) (4) (5). This species is also found as a vagrant in Guatemala (4).
The pine siskin is mostly found in coniferous or mixed forests and favours areas where there is an open forest canopy (2) (3). It can also be found foraging in weedy fields, meadows, grasslands and thickets, as well as backyards and gardens in suburban areas, where it is regularly seen at bird feeders (2).
The movements of the pine siskin are highly erratic and are usually in response to food availability rather than weather conditions (2) (3) (5), with true migration not thought to occur in this species (3). During times of cold weather, the pine siskin is able to increase its metabolic rate to keep warm, raising it up to 40 percent higher than other similarly sized birds (2).
The diet of the pine siskin is mainly composed of young buds and the seeds of conifers, grass, weeds and deciduous trees. It also takes insects and grubs (2) (3) (5), although these only constitute a small percentage of its diet (3). This species is regularly seen around bird feeders throughout its range. It is able to store food weighing up to ten percent of its total body mass within a part of the throat known as the ‘crop’ (2).
Mating pairs of pine siskins are formed between March and May, when the male performs a courtship display involving flying, singing and feeding the female (3) (6). Mating pairs remain monogamous throughout the nesting period (3).
A gregarious species (2) (5), the pine siskin nests in small colonies (2) (3) (5) (6), although a territory around the nest is defended while eggs are being laid and incubated (3) (6). Breeding individuals forage in small groups (5) (6) and occasionally visit the nests of other pairs. The female pine siskin chooses the nest site and builds the nest over five or six days, although the male may contribute small amounts of nest material (2). The nest is a shallow saucer-shaped structure made with grass, twigs, moss, lichens, bark and roots and is lined with moss, hair, fur and feathers (2) (3) (6).
The female pine siskin commonly lays a clutch of three or four eggs between April and late May (3) (6). The eggs are pale green-blue and spotted with brown and black (2) (3) (6), and are incubated for around 13 days by the female alone, who is fed by the male during this period (2) (3) (6). The young pine siskins fledge the nest after around 15 days, and a second brood may be raised after the first (2).
Loss of habitat could be a threat to the pine siskin, although it is highly adaptable and can nest in shrubs and ornamental trees. In some parts of its range, the commercial planting of conifers and a reduction in certain forest types may be beneficial to this species (2) (3).
Industries such as agriculture and gold mining throughout the range of the pine siskin are known to use harmful chemicals which can result in bird mortalities. Collisions with road traffic are also relatively frequent, as the pine siskin is known to forage for minerals on or around roads. Another potential threat to the pine siskin comes from salmonella outbreaks at bird feeders, which can lead to infection and be fatal for this species (2) (3).
There are not known to be any specific conservation measures currently in place for the pine siskin. It would benefit from research into its biology, population numbers and migratory behaviour to establish an appropriate conservation plan (3).
Find out more about the pine siskin:
BirdLife International - Pine siskin:
Cornell Lab of Ornithology: All About Birds - Pine siskin:
The Birds of North America Online - Pine siskin:
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- Crop: the crop is an expanded, thin-walled pouch in the throat of a bird, insect or earthworm. It is a part of the digestive tract, and is used to temporarily store food.
- Deciduous forest: forest consisting mainly of deciduous trees, which shed their leaves at the end of the growing season.
- Incubate: to keep eggs warm so that development is possible.
- Lichen: a composite organism made up of a fungus in a co-operative partnership with an alga. Owing to this partnership, lichens can thrive in harsh environments such as mountaintops and polar regions. Characteristically forms a crustlike or branching growth on rocks or tree trunks.
- Metabolic rate: the speed at which an animal uses energy; the amount of energy it expends in a given time.
- Monogamous: having only one mate during a breeding season, or throughout the breeding life of a pair.
- Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
- Territory: an area occupied and defended by an animal, a pair of animals or a group.
- Vagrant: an individual found outside the normal range of the species.
IUCN Red List (June, 2012)
Cornell Lab of Ornithology: All About Birds - Pine siskin (June, 2012)
Dawson, W.R. (1997) Pine siskin (Spinus pinus) In: Poole, A. (Ed.) The Birds of North America Online. Cornell Lab of Ornithology, Ithaca. Available at:
BirdLife International (June, 2012)
- Ryser, F.A. (1985) Birds of the Great Basin:A Natural History. University of Nevada Press, Nevada.
- Harrison, H.H. (1975) Eastern Birds’ Nests. Houghton Mifflin, New York.