Dark-eyed Juncos (Junco hymenalis) are abundant winter visitors to our area. Our first sightings of these "snowbirds" in the fall remind us that winter is just around the corner. Their departure in the spring usually goes undetected as we become preoccupied with newly arriving migrants. Many of us take these friendly little feeder birds for granted, but at one time birders often carefully examined flocks of juncos in order to add a vagrant species to their lists. Then in 1973, the American Ornithologists' Union "lumped" together 5 different junco species into the single Dark-eyed Junco.The "Slate-colored" Junco is the race, or subspecies, we see here in the eastern U.S. Nowadays, juncos aren't as carefully scrutinized because a sighting of one of the western races (formerly separate species) don't "count." Even so, many birders will still report another race (most often the "Oregon" Junco) here in our area. While other races undoubtedly occur, birders are often pretty lax in their identifications of these western races just because they are no longer full species. These identification mistakes (or a total lack of trying to distinguish races at all) creates a void in our understanding of the true distribution of the subspecies of Dark-eyed Junco, and deprives us of an opportunity to appreciate the many "faces" of this most familiar and confiding bird.
Before we tackle the problematic Oregon Junco, let's look at a less common, but more startling example of a potential subspecies misidentification.
This junco was banded by RRBO on 20 October 1998. Unlike the vast majority of Slate-colored Juncos, this bird (an adult male) has bold white wing bars! We thought we might have a "White-winged" Junco, a rather rare subspecies from the Black Hills of South Dakota. As in White-winged Juncos, the three outer tail feathers and about 70% of the fourth of our bird were white, whereas Slate-colored Juncos usually have the only the two outer tail feathers completely white, with the third being partially white.Alas, upon closer examination, we realized this was just an unusual Slate-colored Junco. White-winged Juncos are larger than Slate-colored Juncos, and generally a paler ashy-gray. They also have larger bills. Our measurements confirmed that this was indeed a Slate-colored Junco. Had we seen this bird in the field, these size differences would have been difficult to ascertain, while the most prominent field marks for White-winged Junco would have stuck out like a sore thumb. Many birders would have jumped to the wrong conclusion, while a careful birder would have disregarded wishful thinking and forced themselves to at least note the dark slate color and correctly identify a Slate-colored Junco.
An excellent illustration of a Slate-colored Junco with white wing bars (an adult male like ours and interestingly from Ontario) is shown in Jim Rising's book, "A Guide to the Identification and Natural History of the Sparrows of the United States and Canada" or the companion "Sparrows of the United States: A Photographic Guide."
If that can be a stumper, the Oregon Junco situation is even hairier. As the example above indicates, Slate-colored Juncos have variable plumages (made even more complex by three recognized geographic races of the Slate-colored subspecies!). Young male and female Slate-colored Juncos can appear in a wide variety of plumages from very pale to the more "standard" slate and white. Birders regularly report Oregon Juncos that are very likely pale Slate-colored Juncos. Oregon Juncos have a "hooded" appearance, with a dark gray or gray head that contrasts with a browner back and pinkish-brown flanks. Slate-colored Juncos can also look like this, although careful examination usually reveals very little contrast between the back of the hood and the back color.
Another diagnostic feature of Oregon Juncos is the convex shape of the gray throat where it meets the breast; it forms a U-shape. Note the shape of the bib on this Oregon-type Junco banded in Dearborn in December 2003 (it remained until March). On the Slate-colored Junco the shape is concave, forming an inverted U-shape on the breast. Nice illustrations of the junco races can be found on the Cornell web site. A really interesting discussion on intergrades between "Slate-colored" and "Oregon" juncos (sometimes called "Cassiar" Juncos) took place on the ID-Frontiers listserv and has been summarized on a web page. Worth reading all the way through, and pondering the photos.
The Michigan Bird Records Committee currently does not document subspecies. However, the Ontario Birds Record Committee does a great job of keeping track of recognizable forms of the birds of the province. In a 1993 article in the journal Ontario Birds, it was stated that there was only one specimen of Oregon Junco for Ontario (but presumably more sight records), and the only specimen of White-winged Junco was determined to be -- you guessed it -- a Slate-colored Junco with abnormal white wing bars. There are also two records of the "Gray-headed" Junco for Ontario.
Taking a second look at juncos opens your eyes to the marvelous variety in this common species. The more juncos you study, the more likely it will be that you will be able to make an intelligent assessment of plumage characteristics, and add to what we know about the races and plumages of these regular dooryard visitors.
