Pine Siskins are either an infrequent or a frequent bird in Vermont, depending on the year and their irruptive patterns. For instance, there were only scattered records for the first half of 2020, but, in the autumn, they were a frequent feature around the state.
There are three subspecies. Differences between them are mostly "weak and clinal" (Pyle 1997) and not backed up genetically (Alvarez et al. 2016), with the exception of one of the Mexican subspecies, Spinus pinus perplexus. In Vermont, the common subspecies is most likely Spinus pinus pinus, although individual variation may obscure possible vagans vagrants from the mid-West (this subspecies is recognized by Pyle 1997, but not Dawson 2020). In any event, Cornell only recognizes two subspecies groups on eBird: the Northern, comprising Spinus pinus pinus and S. pinus macroptera, and the Chiapas groupings. Separating the two is rather simple.
Birds of the World (Dawson 2020) says:
S. p. perplexus (van Rossem, 1938). Resident in highlands of s. Chiapas and w. Guatemala type locality = San Andrés, Chiapas. Somewhat resembles S. p. pinus but ventral streaks are diffuse, secondary bar narrow, and superciliary line gray; averages smaller than even the nominate subspecies. This subspecies is sufficiently distinct in appearance from other taxa of S. pinus that studies are needed to clarify its taxonomic status (Howell and Webb 1995).
The narrow secondary bar he mentions may be difficult to tell except in flight, although it's possible that this secondary bar refers to wing bars. I was unable to find any bars on the secondaries in any photos on eBird, so I'm unclear what this means.
Pyle (1997) doesn't differentiate the Chiapan subspecies, as his book is largely concerned with American birds. However, he does mention that it can be difficult to separate S. pinus pinus from Eurasian Siskin when there is a green morph.
A more recent study, Alvarez et al. (2016), showed that Spinus pinus perplexus is genetically different and could possibly be its own species. They write this about field markings:
Spinus p. perplexus individuals are pale gray, with a variable amount of streaking, and have extensive yellow pigmentation on the wings (Dawson 1997). Some individuals show a dark wash on the crown, similar to that of S. atriceps, which is otherwise mostly olive and unstreaked (Fig. 1A, Supplementary material Appendix 1, Fig. A1), a pattern that has led some authors to propose that S. p. perplexus could be the result of hybridization between S. pinus and S. atriceps in Chiapas and Guatemala, and may even constitute a lineage of hybrid origin (Van Rossem 1938, Howell and Webb 1995).
(NB: Dawson 1997 was an early version of Dawson 2020). The hybrid theory did not stand up to their genetic analysis. Most interestingly, this passage highlights that there are different morphotypes of S. pinus perplexus, besides the pale gray morph. Another paper, Vallely et al. (2014), talks about the streaked morphotype, which would look superficially similar to S. pinus pinus:
Streaked morphotype. — This form includes the holotype and type series of S. pinus perplexus and is the most variable morphotype. It is streaked very dark brown (21’’’b) and pale brown (21’’’m) from crown to lower back. Overall coloration is variable, but is always greyer (less warm or brownish) than other forms of S. pinus. Streaked-morph birds are also usually darker overall than in other forms of S. pinus, including on the crown. The streaking varies from soft to moderately crisp, but is usually less contrasting and well defined than in other forms of S. pinus. The rump varies from pale beige (21’’’d / 17’’’d) to concolorous with the mantle, or from very pale yellow to dusky yellow, and usually shows some streaking. The face, breast and flanks vary from streaked pale greyish brown (21’’’’b) and whitish, to broad, soft, brownish-grey streaking with the white markings narrower, yielding a more muted, uniform appearance. The belly and vent are whitish, or yellowish white in two juveniles, and the undertail-coverts are streaked brown. Wing-coverts are narrowly tipped whitish, beige or olive-beige, and may show narrow yellowish lateral fringes to the greater coverts. The tertials are narrowly fringed whitish or yellowish and tipped whitish (Fig. 2g, h). Some streaked birds with juvenile rectrices are similar in plumage to adults.
Differentiating streaked forms may be difficult in the field, but the brown undertail-coverts, grey coloration, and diffuse streaks should be clear tells for Chiapan birds. (Although largely irrelevant for Vermont purposes, it may occasionally also be difficult to tell S. pinus perplexus from Spinus atriceps, with which it may hybridize.)
eBird also has another grouping, for the green morph birds. Assumedly, most of these birds are also Northern Pine Siskins, and the average Pine Siskin doesn't need to be differentiated from the other groupings when submitting a checklist.
Logging this bird on eBird may be useful for science: Alvarez et al. (2014) mentions the lack of vagrant S. p. pinus/macroptera sightings in Chiapas on eBird as a sign of geographical isolation.
To date, there are no records on eBird of other subspecies in Vermont. The record listed when this page was created was the first record of the Northern Pine Siskin in Vermont with media.
Nomenclature:
Salient identification points:
Example Records:
Local subspecies records:
Needs:
These needs reflect eBird's database, and whether the bird has photos, audio, or sightings in a given area. "None" denotes that this species has been satisfactorily documented.