The American Goldfinch (Spinus tristis) is a small North American songbird in the finch family Fringillidae. Its classification has been defined over the years based on morphological, behavioral, and genetic analysis.
Quick Answer
The American Goldfinch is classified in the following taxonomy:
- Kingdom: Animalia
- Phylum: Chordata
- Class: Aves
- Order: Passeriformes
- Family: Fringillidae
- Genus: Spinus
- Species: S. tristis
Scientific Classification
The American Goldfinch belongs to the kingdom Animalia, which includes all multicellular, eukaryotic organisms. As a vertebrate, it is placed in the phylum Chordata. More specifically, it belongs to the class Aves as a bird species. The order Passeriformes includes all perching birds and the family Fringillidae refers to finches. The genus Spinus contains North and South American goldfinches and siskins. The specific epithet tristis refers to the melancholy call of the American Goldfinch.
Below is a summary of the scientific classification of the American Goldfinch:
Taxonomy | Category |
---|---|
Kingdom | Animalia |
Phylum | Chordata |
Class | Aves |
Order | Passeriformes |
Family | Fringillidae |
Genus | Spinus |
Species | S. tristis |
History of Classification
The American Goldfinch was first described scientifically by Carl Linnaeus in 1758 in the 10th edition of his Systema Naturae. Linnaeus originally named it Fringilla tristis and placed it in the finch genus Fringilla.
For much of the early 19th century, the American Goldfinch was moved between different finch genera including Carduelis, Chrysomitris, and Astragalinus. In 1838, William Swainson established the genus Spinus for the goldfinches and siskins, with the American Goldfinch designated as Spinus tristis.
19th Century Revisions
During the late 1800s, the American Ornithologists’ Union (AOU) made revisions to the scientific names of North American birds. In 1886, the AOU moved the American Goldfinch back to the genus Chrysomitris. Then in 1898, it was returned to the original genus Fringilla established by Linnaeus. However, neither revision gained wide acceptance.
20th Century Confirmation
By the early 20th century, the genus Spinus proposed by Swainson became widely accepted. In 1944, the AOU officially recognized Spinus tristis as the scientific name for the American Goldfinch.
Recent genetic analysis in the late 20th and early 21st centuries has confirmed the distinctive evolutionary history of Spinus compared to other finch genera. This has validated Swainson’s original designation that continues to be used today.
Unique Characteristics of Spinus tristis
The American Goldfinch possesses a distinctive combination of morphological and behavioral traits that differentiate it from closely related finch species and support its classification in the genus Spinus:
- Small size and a short notched tail
- Sexual dimorphism in plumage coloration (males bright yellow, females dull brown)
- Unique molt cycle allowing seasonal plumage change
- Thistle seed-adapted conical bill
- Distinctive flight pattern with roller coaster-like undulations
- Melancholy vocalizations
- Delayed breeding season timed with seed availability
Many of these adaptations are suited for taking advantage of late summer/fall seed crops, especially thistle, that provide critical food resources. Similar ecological specializations are seen in its close Spinus relatives.
Affinities with New World Goldfinches
Phylogenetic studies indicate the American Goldfinch’s closest relatives are the Lesser Goldfinch (Spinus psaltria) of the southwestern U.S. and Lawrence’s Goldfinch (Spinus lawrencei) of California. These three species diverged from a common ancestor around 3 million years ago.
Other close relatives in the Spinus genus include:
- Eurasian Siskin
- Pine Siskin
- Black-capped Siskin
- Hooded Siskin
- Antillean Siskin
All these species occupy similar ecological niches specializing in seeds, especially from trees like birch, alder, and thistle.
Relationship to Eurasian Siskin
The Eurasian Siskin was previously considered conspecific with the North American Pine Siskin as just two subspecies of S. spinus. However, the two were split into separate species S. spinus and S. pinus in the early 2010s based on differences in morphology, vocalizations, and genetics.
The evolutionary divergence between the Pine Siskin and Eurasian Siskin is analogous to the relationship between the American Goldfinch and its close Spinus relatives. In both cases, an ancestral finch colonized North America and diverged into new endemic species occupying similar niches as their Old World counterparts.
Conclusion
In summary, analysis of morphology, ecology, behavior, biogeography, and genetic relatedness provide overwhelming evidence that the American Goldfinch belongs to the genus Spinus. Its official scientific name of Spinus tristis accurately reflects our understanding of its evolutionary history and relationship to other finches. While some revisions to the genus were proposed historically, Swainson’s original Spinus designation in 1838 has withstood the test of time.