Identifying adult California Gulls and Ring-billed Gulls in flight

In much of the inland western United States and Canada, there are two common breeding white-headed gull species, the California Gull and the Ring-billed Gull.  If you live in this region, the first step in learning your gulls will be to learn to tell adults of these two common species apart.  When they are perched on the ground, it is not difficult: California Gulls have dark eyes, red and black on the bill, are slightly larger, and have a slightly darker mantle (back).  In contrast, adult Ring-billed Gulls have light eyes, a black ring around the bill without red, are slightly smaller, and have a paler mantle.

A pair of adult California Gulls in breeding plumage, showing their dark eyes, red and black on the bill, and relatively dark mantle.  Photographed 13 Apr 2009 at Logan, Utah.

An adult Ring-billed Gull in breeding plumage, showing its pale eye, black ring around the bill without red, and relatively pale mantle.  Photographed 2 May 2011 at Blackfoot, Idaho.

Even with these relatively distinctive gulls, identifying them in flight can often be difficult.  Sometimes, it is possible to make out the same features in flight, especially with close looks in good light.  Look especially for the eye color and the bill markings, because size and mantle color are particularly difficult to judge on a bird in flight.

Adult California Gull in breeding plumage.  Even in flight, the pattern of black and red on the bill and the dark eye can be obvious.  Photographed 17 Mar 2013 in Mendon, Utah.

Adult Ring-billed Gull in breeding plumage.  Even in flight, the black ring on the bill (without red) and the pale eye can be obvious.  Photographed 17 Mar 2013 in Mendon, Utah.

The real challenge, however, is in identifying these species when they are high overhead or lit in such a way that the eye color and bill pattern are impossible to distinguish.  In this case, it is helpful to pay close attention to the pattern and colors under the wing.  Both species have mostly whitish wings with extensive black near the tips and white spots at the very ends of the outer flight feathers.  But, California Gulls have duskier inner primaries contrasting more with the rest of the wing, and Ring-billed Gulls have paler inner primaries that are about the same color as the rest of the wing. California Gulls also tend to have more black in the wingtip than Ring-billed Gulls, but there is some overlap in this trait. 

Note the darker gray band that stretches from the black wingtips into the outer secondaries on this adult California Gull.  With practice and good light, this contrast could be visible from great distance on overhead birds.  California Gulls also tend to have more black in the wingtips, but there is some overlap in this trait.  Photographed 17 Mar 2013 in Mendon, Utah.

In contrast to the California Gull above, this Ring-billed Gull has much paler inner primaries and outer secondaries, which contrast less than on the California Gull.  Some slight contrast is still evident, so it might take some practice in the field to get a feel for this field mark.  Ring-billed Gulls also tend to have less black in the primaries, but there is some overlap in this trait so it should be used only as a supporting character.  Photographed 17 Mar 2013 in Mendon, Utah.

California Gull in flight.  Note again the relatively grayish inner primaries and outer secondaries, contrasting with the paler underwing coverts.  Photographed 9 Feb 2008 in Logan, Utah. 

Ring-billed Gull in flight.  The relatively pale inner primaries and outer secondaries almost lack contrast with the underwing coverts.  Note that the extent of black visible in the primaries varies to some degree with the position of the wing and the individual, so this bird appears to have about the same amount of black as the California Gull above.  Photographed 9 Feb 2008 in Logan, Utah.

The differences in underwing pattern between these two species are subtle, and take field experience to get a good understanding of them.  Of course, not every gull will be identifiable in every situation.  But with practice, you can learn to identify a higher percentage of gulls, even when they are seen only in flight high above you.

Mexican Duck in Utah

Mexican Duck, Anas (platyrhynchos) diazi, at First Dam, Logan, Utah.  Copyright Ryan P. O'Donnell.  

If you follow Utah Birdtalk/Birdnet, you already know that on February 5th, about two weeks ago, my friend Craig Fosdick found a very interesting duck at First Dam in Logan, Utah.  It was a Mexican Duck; probably the northernmost record of the species, and only the third from Utah.  Mexican Ducks are easy to overlook, and many readers of this blog might have never heard of one before.  Even the experienced birders Craig was with at the time hardly gave this unique vagrant a second look.

First, what is a Mexican Duck?  That question is not easy to answer.  According to the American Birding Association and the American Ornithologists Union, it is a subspecies of Mallard.  But that view is considered by some to be antiquated and inaccurate.  Recent genetic work has shown that the Mexican Duck may actually be its own species, and it is at least as unique as several other species such as the Laysan Duck and the Mottled Duck.  The picture is complicated, however, because Mallards contain several genetic lineages, and thus to have species boundaries that reflect mitochondrial gene phylogenies, one would either have to split Mallards based on strictly genetics, or else consider "Mallards" to include Laysan Ducks, American Black Ducks, Mottled Ducks, and many others, which obviously does not reflect biology well.  This is an area that is in need of additional research, particularly in generating phylogenies and assessing hybridization with nuclear molecular markers.

Phylogeny of Mallard-group ducks, modified from Johnson and Sorenson 1999, based on mitochondrial DNA sequences.  Note that Mallards appear twice here, having (at least) two different mitochondrial sequences.  Also note that Mexican Ducks are as distinct from Mallards as many other groups that we know of as species.

The definition of species within the Mallard group is confusing, but perhaps even more so in the case of Mexican Ducks, because our understanding of this species is clouded by hybridization with Mallards in Arizona and New Mexico.  A classic study of morphology in Mexican Ducks found that there are virtually no pure Mexican Ducks anywhere in the species range, according to a numerical scale of morphology that ranges from pure Mexican Duck to pure Mallard.  However, an alternative interpretation of the same dataset is that our definition of what identifies a pure Mexican Duck is too narrow, and that pure Mexican Ducks can show traits that have once been taken to be indicative of Mallards.

With respect to the duck seen as recently as yesterday in Logan, this appears about as close to a pure Mexican Duck as one can expect at the northern part of the range of the (sub)species.  There is very little green on the head.  The bill is bright yellow.  The tail shows no patches of white.  The speculum has green iridescence, and is bordered only thinly by white.  The rump and undertail coverts match the flanks well in color, showing no obvious indication of the black that a male Mallard has in these areas.  The belly is dark, matching the color of the rest of the bird well.  The only part that seems to show some obvious Mallard ancestry is that the central retrices (tail feathers) curl up slightly off the plane of the tail, hinting at the curled central tail feathers of an adult male Mallard.  But, with how little we know of "pure" Mexican Ducks, perhaps this is not outside the range of variation shown by them?  Only an extensive study of morphological variation and nuclear DNA across the range of the Mexican Duck and Mallard can really address this question well.

The Mexican Duck looks a lot like a female Mallard, but darker and (in a male, such as this one) with a bright yellow bill.  Copyright Ryan P. O'Donnell.

The Mexican Duck's speculum has more of a green iridiscence, compared to the purple of a Mallard's, although the color varies somewhat with the angle of view.  Also note here how, unlike a male Mallard, the rump is about the same color as the flanks and the tail is dark, without white.  Copyright Ryan P. O'Donnell.

Unlike a Mallard, the lower belly is not noticeably paler than the flanks or breast.  The bright white underwing coverts are a trait shared by male Mexican Ducks and male Mallards.  Copyright Ryan P. O'Donnell.

This angle can be tough to see in the field, but it shows how the back of the Mexican Duck is generally dark, and the speculum is only thinly bordered by white, not boldly bordered by white like a Mallard's speculum.  Note that at this angle the speculum looks more purple than green, like a Mallard's.  Copyright Ryan P. O'Donnell.

As rare birds go, this individual might be pretty easy to find.  It has been seen over the last two weeks at First Dam in Logan.  Watch for a duck that looks a bit like a female Mallard, but is darker and has a bright yellow bill.  While I don't advocate feeding park ducks, it is a common practice at this park, and if you happen to time your visit when a local is feeding them, this duck might come right out in the open and fight with the other local domestic breeds for bread.  Otherwise, you might get lucky and see it swimming around on the water, or it might be sleeping on the far shore of the lake.  If it's not out in the open when you get there, try patiently scanning the sleeping ducks along the shoreline.

The Mexican Duck being seen at Logan's First Dam seems to have paired up with a female Mallard.  Note in this view how this Mexican Duck's central retrices lift slightly off the others, perhaps indicating a small amount of Mallard heritage.  Copyright Ryan P. O'Donnell.

White-crowned Sparrow Subspecies in Utah

One of the things that I love about birding is that the challenges never stop coming; there's always more to learn.  Once a birder has a pretty good handle on the species found in his or her area, they often move on to trying to tell subspecies apart.  This might sound quite intimidating at first, but for some subspecies, it can be pretty easy.

There are two subspecies of White-crowned Sparrow that regularly occur in Utah.  Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha; also called "Interior West White-crowned Sparrows") breed here, as you might expect, mostly in the mountains.  Gambel's White-crowned Sparrows (Z. l. gambelii) winter here, having migrated down from their breeding range in the western taiga of northern Canada.  Around the same time Gambel's are arriving from the north, the Mountains are heading south, leaving the state to winter in southern Arizona and northern Mexico.  There are a few eBird records of Mountain subspecies wintering in Utah, but I've never actually seen one documented here in Utah: I suspect it is very rare if it occurs at all in Utah in winter, but please comment below if you've documented Z. l. oriantha in Utah in winter.

Telling these two subspecies apart is relatively easy.  Gambel's have a yellowish bill and pale lores; Mountains have a pinkish bill and dark lores.  (The lores are the area between the eye and the bill.  Look to see whether the dark line that both subspecies have behind the eye continues in front of the eye to connect with the stripe on the side of the crown.)  Bill color is a little less reliable in young birds, but even the young ones usually have the appropriate color lores.

It is always possible that one of the other three subspecies of White-crowned Sparrows could show up in Utah, but this would be very unlikely.  Start by practicing telling these two subspecies apart, and you'll be more prepared for a vagrant of another subspecies.  For more on distinguishing subspecies of White-crowned Sparrows apart, see this and this post from David Sibley; for the VERY interested, see this extensive treatment, also by Sibley.

Adult Mountain White-crowned Sparrow, Z. l. oriantha,  Logan, Cache County, Utah.  11 May 2011.

Adult Mountain White-crowned Sparrow, Z. l. oriantha, Antelope Island, Davis County, Utah.  7 May 2011.

Adult Gambel's White-crowned Sparrow, Z. l. gambelii, Washington County, Utah.  19 Mar 2011.

Immature Gambel's White-crowned Sparrow, Z. l. gambelii, Cache County, Utah.  20 Feb 2011.

Immature Gambel's White-crowned Sparrow, Z. l. gambelii.  Gunlock Reservoir, Washington County, Utah.  16 Mar 2007.

Probably an adult Gambel's White-crowned Sparrow, Z. l. gambelii, Beaver Dam Wash, Washington County, Utah.  28 Nov 2009.  This individual appears to have an unusually dark bill relative to most Gambel's.  Are those brownish sides?  Are the white stripes dingier than expected for Gambel's?  This might be worth looking at again when I get more experience: is this possibly a vagrant of a Pacific Northwest subspecies?

(All photos copyright Ryan O'Donnell)

Spiders of Utah

A Platycryptus sp. jumping spider on a wall in Logan, Utah. ©Ryan O'Donnell and Stephanie Cobbold, 2011. 

Would you like to learn more about spiders, in Utah and around the world?  Stephanie Cobbold's PhD dissertation is on some of the spiders of Utah. Lately we've been taking lots of spider photos, and she's been sharing some of them at her blog. Check it out!

Lesser Sandhill Crane?

While out this afternoon, I photographed a Sandhill Crane in Benson, Cache County, Utah that was significantly smaller than its 20 or so companions. I've been under the impression that the only subspecies of Sandhill Crane expected in Utah is Greater (Grus canadensis tabida). This one looked to me like a Lesser Sandhill Crane (G. c. canadensis). However, I don't know whether I've ever seen the third migratory subspecies, Canadian Sandhill Cranes (G. c. rowani), which are intermediate in size between Greaters and Lessers. eBird is of little help here because apparently no Sandhill Crane records from Utah in eBird have been identified to subspecies. Does anyone know anything about subspecies of Sandhill Crane in Utah? Does this (left-most bird) look like a Lesser to you?

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.