Ottawa, ON • CANADA
Among the population of the slate-coloured subspecies of Dark-eyed Junco (J. h. hyemalis) there are rare variants with white wingbars, created by white tipped wing-coverts (Nolan et al., 2002). Sibley (2014) notes that the probability of occurrence of the white-winged variant, with wingbars as prominent as J. h. aikeni, in the Slate-colored Junco population to be 0.005 (that is 1/200 or 0.5%). I thought this to be a liberal estimate based solely on my experience of searching for a variant over many years through seemingly hundreds if not thousands of juncos. The Birds of North America (BNA) Online account references the probability of occurrence of white-winged individuals in the J. h. hyemalis population to be 0.03 (that is 3/100 or 3%) which is much greater than that suggested by Sibley (Nolan et al., 2002).
On 07 February 2018, I was watching the birds visiting my bird feeders in the backyard. One particular slate-coloured Dark-eyed Junco (Junco hyemalis hyemalis) caught my eye. It appeared to me to have a flash of white on the wing as it moved about. Sometimes a feather out of place or one from the breast can stick out when the wing is in the folded position, creating the illusion of white in the wing. I waited for it to come closer and give me a better view. I looked at it through my binoculars and then took some photos of it. It appeared to be a true variant Slate-colored Junco (J. h. hyemalis). I have been waiting for a bird like this for a very long time.
I noted that it appeared to be a male and a presumed adult bird in basic plumage. The amount of white appears to be even on both wings showing on the greater secondary covert tract as well as a bit on the median secondary covert tract. I counted at least four greater secondary covert feathers with white tips and a fifth with less white than the others. This bird is showing ~5/8 visible greater secondary covert feathers that have white on the tips. So it had at least partial wingbars and actually appears to be very similar to a bird that I observed in Niagara-on-the-Lake in 2014 (this bird is mentioned and showed below at the end of post).
I tried to take photos from as many angles as possible to document and examine the wing covert, tertial and rectrix feather detail. All photos were taken from inside a house through a window on an overcast day with poor light.
Here are a couple of photos of the back of the bird from slightly different angles, below.
Below are some more photos of the bird from both sides.
The lighting was harsh and very low and the windows were not perfectly clean so it made taking photos difficult. The bird moved into and perched in the Cedar hedge which provided a different setting. The dark background resulted in photos with a different exposure than the photos that have a great deal of snow in the background.
Just to rule out the far-fetched possibility of a vagrant White-winged Junco (J. h. aikeni) I tried to get a photo of the spread tail in order to count the number of white outer tail feathers. I managed to get one photo that is quite blurry but I believe it shows that the bird has two fully-white outer tail feathers on each side (versus the expected three in J. h. aikeni) suggesting J. h. hyemalis. I think the fact that the white-tips do not apparently extend across all greater coverts is also another field mark in favour of Slate-colored. At this link HERE there is an example of another presumed variant slate-colored Dark-eyed Junco (J. h. hyemalis) photographed in Hillsboro, New Mexico, U.S.A in January 2016, that appears to have a full bar across the tips of the greater coverts (to a greater extent than the subject bird above), which the author reasons is not J. h. aikeni (The Natural Observer, 2016).
It was with a group of Dark-eyed Juncos that have been around all winter, I assume. There are usually about 7-11 of them in the backyard. I will keep an eye out for it and try to get more photos.
I did once see a junco that I suspected was a ‘white-winged variant’ in the Niagara Falls area in 2014, during the OFO Gull Weekend from 28-30 November 2014. It was at the same feeder that there was an Eurasian Tree Sparrow being seen at. There were many birders that were in town for the gull weekend so many people had the opportunity to see this bird but I think it flew under the radar for the most part. It shows how hard it can be not only to find a variant Dark-eyed Junco but also how easy it can be to overlook one. The bird feeder that they were visiting was so distant though that it was difficult to get a good look. I have two photos of the 2014 bird and have included them below. The first one is technically the only photo that I managed to get of it and the second photo is a cropped and lightened version.
Nolan Jr., V., E. D. Ketterson, D. A. Cristol, C. M. Rogers, E. D. Clotfelter, R. C. Titus, S. J. Schoech and E. Snajdr. 2002. Dark-eyed Junco (Junco hyemalis), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA. https://doi.org/10.2173/bna.716
Sibley, D. (2014). The North American bird guide. London: Bloomsbury.
The Natural Observer. 2016. Black Range Rag. http://www.blackrange.org/The_Black_Range_Rag/Blog__The_Natural_Observer/Entries/2016/1/9_Entry_1.html