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.

Hybrid Bunting in Salt Lake City

On a recent trip to Salt Lake City, I took a short birding trip in City Creek Canyon, a location that comes up often on the Utah birding listservs. It was neat to see several species whose boundaries seem to be in the short distance between SLC and Logan, like the Western Scrub-Jay, which generally doesn't occur in Cache Valley, and the Blue-gray Gnatcatcher, which can be found in Cache County but only with difficulty. But the highlight of this little walk was a unique bird that I had not seen before. The bird looked mostly like an Indigo Bunting, a species that is typical of the eastern US, but which occurs in Utah rarely. Except, unlike a pure Indigo Bunting, it had a white belly. I think that this indicates that my bird was a hybrid of an Indigo Bunting and a Lazuli Bunting, the common bunting of the west. These two species do hybridize with some regularity, and a quick Google search turned up many examples of birds that were similar to the bird I saw. It would have been nice to see a pure Indigo Bunting, a rare species in the state, but it is some consolation that this hybrid combination is probably even more rare!

Explaining to do

Okay, it seems I have some explaining to do. I my last post, I thought I had found a Thayer's Gull. Several things about the bird didn't seem quite right to me, and I thought it might even be a Glaucous-winged Gull, which is much rarer in Utah (although Thayer's are also pretty rare here). So, I sent photos and videos to several list-serves requesting help in my identification. I received responses from nine different people, and as any student of the gulls would guess, there was little consensus. Opinions ranged from pure Thayer's Gull to pure Glaucous-winged Gull to pure Slaty-backed Gull, but the most common opinion was that I had photographed a hybrid between a Glaucous-winged Gull and a Herring Gull. This was one of the possibilities I had considered, but it wasn't the identification I thought was most likely. Even after hearing all the opinions of the experts, I am still not confident in identifying this bird, and it will stay in my records as "Unidentified gull, probable Glaucous-winged x Herring hybrid".

Someone asked me before if it's embarrassing to publicly misidentify a bird. If I had called this something outlandish, then maybe I would be embarrassed. But gulls are notoriously difficult, and I feel pretty good about how I did with this one. In fact, David Sibley says of the Thayer's Gull, "Very difficult to distinguish from hybrids of other large gulls such as Herring x Glaucous-winged." After all, if the gulls can't even tell each other apart when it's time to find a mate, how can we be expected to sort them out as juveniles!

Okay, so I'm not counting the Thayer's Gull that I posted about before. Then why is Thayer's Gull still in my year list at the right? Well, I feel more confident in the identification of a different bird that we saw on the same day was a Thayer's Gull. One photo of this bird is above: the Thayer's is on the left and a California Gull is on the right. This Thayer's Gull has darker wingtips than my previous mystery gull, but it has a distinctly small, round head and petite bill, two traits I was looking for on the mystery gull but was having trouble with. So, the photo may be wrong, but I still think I saw a Thayer's Gull that day. Although I'd be happy to hear comments from the experts about this gull as well.