The pine siskin (Spinus pinus) is a small songbird native to North America. With its streaky brown plumage, sharp bill, and notched tail, it bears a resemblance to its close relative, the American goldfinch. This often leads to some confusion around exactly what type of bird the pine siskin is. So is a pine siskin a finch? Yes, the pine siskin is a type of finch. More specifically, it is a member of the genus Spinus within the finch family Fringillidae.
Pine Siskin Classification
The pine siskin belongs to the following scientific classification:
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Fringillidae (Finches)
Genus: Spinus
Species: Spinus pinus
So while its common name is “pine siskin,” its scientific name reveals its relation to other finches. The genus Spinus contains the North American goldfinches and siskins. Other close finch relatives include the house finch, purple finch, and Cassin’s finch.
Physical Features of Pine Siskins
Pine siskins share many physical traits with their finch relatives:
- Small size (4.5-5.5 inches in length)
- Cone-shaped bill adapted for eating seeds
- Notched tail
- Pointed wings
- Yellow wing bars
- Streaky brown plumage
- Sharp, chinchy call
In particular, pine siskins closely resemble American goldfinches. While the goldfinch has bright yellow plumage, the pine siskin is more brownish-gray. The pine siskin also has more heavy streaking on its underparts. Their songs are very similar.
Male vs. Female Pine Siskins
There is some sexual dimorphism between male and female pine siskins:
- Males have a brighter yellow color on the wings and at the base of the tail.
- Females are more heavily streaked overall.
- Males have a longer, more deeply forked tail.
However, the differences are subtle enough that it can be difficult to distinguish males from females by sight alone.
Behavior and Habitat
In terms of behavior and habitat preferences, pine siskins again show their finch nature:
- Gregarious – often found in large flocks.
- Forage in trees and bushes for seeds.
- Can hang acrobatically while feeding.
- Mainly eat seeds from conifers and birches.
- Breed in coniferous or mixed forests.
- Migratory habits vary by region.
Goldfinches share these same behavioral traits and habitat preferences. Pine siskins also form large winter flocks and migrate in an irruptive pattern based on food supplies like other northern finches.
Song and Call
The vocalizations of pine siskins offer more evidence of their finch lineage. Their songs are complex and musical, consisting of trills, buzzes, and warbles. Siskins produce a metallic “zreeep” call while flying. At feeders, they have chatter-like “chrrt” calls. All of these vocalizations are highly reminiscent of American goldfinches.
Song Comparison
Here is a simple notation comparing the songs of pine siskins and American goldfinches:
Pine Siskin Song:
Feeeeeee-oh-seeeeeee-see-see-see-zreeeee
Goldfinch Song:
Per-chic-o-reeeee, see-see-see, let’s see here
The complex, twittering songs of these two finch relatives are clearly very similar. Their calls are even more alike, often making the species indistinguishable by sound alone.
Relationship with Goldfinches
So why is there confusion around pine siskins if they are so closely related to goldfinches? Part of it may be their superficial similarity to some sparrows. But more significantly, pine siskins and American goldfinches sometimes hybridize where their ranges overlap.
Pine Siskin-Goldfinch Hybrids
Hybrids between pine siskins and American goldfinches exhibit intermediate features:
- Plumage is a mix of brown/gray and yellow.
- Bill size and shape blend those of the parent species.
- Songs combine elements of each species.
- Some hybrid males may sing a pine siskin song but look like a goldfinch.
These hybrid “siskin-finches” can confuse birders who are trying to identify one species or the other. But it provides even more proof that pine siskins and goldfinches are close genetic relatives despite some superficial differences.
Taxonomic History
The taxonomy and classification of the pine siskin has been debated over the years:
- Originally classified as Carduelis pinus by Linnaeus in 1758.
- Sometimes placed in the genus Spinus, sometimes in Carduelis.
- Considered congeneric with the Eurasian siskin.
- Grouped with the Asian siskins at times.
- Occasionally lumped in with American goldfinches.
- DNA studies have confirmed relation to Spinus finches.
Through all of this, scientists have recognized the pine siskin as a finch. Disagreements have centered on its relationship to other finch species across different continents. Modern genetics research indicates its closest relatives are other North American finches.
Conclusion
Despite some taxonomic uncertainty and subtle differences from its goldfinch cousins, the prevailing evidence overwhelmingly supports the pine siskin’s identity as a finch:
- It belongs to the scientific family Fringillidae, which contains all true finches.
- It shares physical traits and behaviors with other finches.
- Its vocalizations are very finch-like.
- It readily hybridizes with the American goldfinch.
- DNA analyses confirm its phylogenetic relationship to other Spinus finches.
So the next time you see a flock of fast-moving birds with streaky brown plumage feeding on conifer seeds, you can confidently call them pine siskins. Remember that siskins are simply a type of wild finch that has evolved adaptations for extracting seeds from pine cones across North America’s forests.