A Hybrid Dusky Grouse x Sharp-tailed Grouse

A Dusky Grouse x Sharp-tailed Grouse hybrid, photographed by the author in northern Utah on 7 Apr 2013.

I love hybrids.  Some birders can be disappointed by hybrids, especially when a locally rare species turns out to not be "pure" (and thus can't go on a list).  But for me, they have everything you could look for in a bird: They are generally very rare: even the more common hybrids are rarer than their parent species.  They are often a challenge to identify.  And they give us a peak into the process of evolution: why don't we see more hybrids, and if two species can produce hybrids, why are they considered species?

I was hiking around a local birding spot (Hardware Ranch W.M.A.) a couple weeks ago, and I saw what I thought at first was a Sharp-tailed Grouse.  This bird was running through the sagebrush, with its tail held high, showing bright white undertail coverts, like Sharp-tailed Grouse do.  It had a slightly crested head, and an overall yellowish tone, also fitting Sharp-tailed Grouse.  But when I got my binoculars on it, I could see the black tail feathers with broad charcoal tips, a clear mark of a Dusky Grouse.  I was able to grab a couple photos before the bird flushed, and flew off through the sagebrush.

Later, I became suspicious that I had photographed a hybrid.  Hybridization between these species had been documented once before, by Allan Brooks in 1907 (illustration below).  I sent the photos around to a few grouse experts I knew, and a few people who knew grouse experts, and all the replies came back that this was indeed a hybrid Dusky Grouse x Sharp-tailed Grouse.  Interestingly, although I haven't been able to find any other photographs of this hybrid, one biologist indicated that this is the most frequently observed hybrid combination between wild grouse.  Local biologists have told me that they have seen a male Dusky Grouse displaying among a lek of Sharp-tailed Grouse about 25 miles (40 km) north of where I photographed this bird.  That same male Dusky, in fact, even tried to mate with a Sharp-tailed Grouse while the biologists had it caught in a trap!

A Dusky Grouse x Sharp-tailed Grouse hybrid, illustrated by Allan Brooks and published in the Auk in 1907.

The same Dusky Grouse x Sharp-tailed Grouse hybrid shown above.  This is the second of the only two photos I was able to take before the grouse flushed.

(Thanks to Mike Wolfe, Timothy Taylor, Scott Gardner, Mike Schroeder, and Jack Connelly for sharing their thoughts on this bird.)

Possible Dark-eyed Junco x Song Sparrow Hybrid

This afternoon I photographed an interesting DARK-EYED JUNCO in my yard in Logan, Cache County, Utah. The bird had most of the basic traits of a female Oregon subspecies Dark-eyed Junco, except for a few anomalies. Most obvious was a soft-edged buffy malar ("mustache") stripe that matched the flanks in color. I grabbed a few quick photographs through the window, but could not relocate the bird when I went outside to try for better photos. In the photographs, I noticed that the bird also has a hint of a pale supercilium ("eyebrow"), a slightly more striped back than expected (although perhaps not entirely outside the range of variation for a pure DEJU), and the white in the outer tail feathers appears to not reach the tip of the tail, instead fading to black.

The combination of anomalous traits make me think this is not just an aberration, but more likely a hybrid of some kind. Hybrids between DEJU and sparrows of the Zonotrichia and Melospiza genera have been previously reported. It seems to me like the best match for this bird would be a Dark-eyed Junco x Song Sparrow hybrid, a combination which has been reported before. (For example, here is a link to a possible photo of another DEJU x SOSP hybrid, and here is a link to an article describing another.) It is my opinion that the only way to be 100% certain of any hybrid parentage is with genetics, but I think this is the most likely explanation for this bird based on the traits observed, the frequency and range overlap between the species in question, and the fact that hybridization between these two has been documented previously. The Song Sparrow-like traits are pretty weak on this bird, so a backcross (the offspring of a mating between a pure DEJU and a DEJU x SOSP hybrid) also may be likely. Any thoughts or comments on this bird are welcome.