Category Archives: identification challenges
Nala and I walked along the Columbia River from Broughton Beach to the Sea Scout base.
Greater Scaup was the most numerous species on the river, with smaller numbers of Lesser Scaup (fifth bird from the right)
Great Scaup (upper left) with Lesser Scaups, showing a nice comparison of size and head shape.
Young Spotted Towhees have been showing up at the feeder. It is always fun to see them, as they look so different from their parents. This plumage can be confusing to those unfamiliar with it, but there are clues to the bird’s identity, other than the parents that are usually nearby.
Despite the overall dark coloring, they still show spots on their wing coverts, like their parents. By the time they leave the nest, they possess the large size and long tail of the adults. Like most fledgelings, the young towhees show yellow at the gape (corner of the mouth).
Westmoreland Park, in southeast Portland, is always worth a quick visit in winter.
Westmoreland is also a good spot for studying the various subspecies of the white-cheeked goose complex. This is a Taverner’s Cackling Goose, identified by her medium bill (covered in down for some reason), blocky head, and pale breast.
Western Canada Goose bathing
There are two statements that will immediately and significantly damage a birder’s credibility: “I’m sure of the ID, because the bird looked exactly like the picture in my field guide.” and “It couldn’t be that species because it doesn’t look like the bird in my field guide.”
The fact is, no bird looks exactly like the picture in the field guide. Field guide illustrations are either an artist’s interpretation or a photo of a particular individual at one moment in time. Every bird is slightly different from every other bird. Rather than looking for birds that are an exact match to a picture, our goal in field identification is to combine elements of size, shape, color, pattern, sound, and behavior into a recognizable species.
Here we have a “textbook” Thayer’s Gull in winter plumage. The head is round, giving the bird a petite or gentle expression. The eye is dark, the underside of the primaries show a lot of white, and the bill is that characteristic greenish-gray color with a bright yellow tip.
This Thayer’s Gull is not quite as round-headed as the previous bird, and the the bill is more yellow, but everything else seems OK. Head shape will vary with the bird’s position, and males tend to be more “robust” than females. So we have a little variation on this bird, no need to panic.
The forehead on this bird is really flat, like that of a Herring Gull, and the bill is noticeably longer. The white underside of the outer primaries is still good for Thayer’s. If you zoom in, you can see the pink orbital ring, also good for Thayer’s. While some Herring Gulls show dark flecks on the iris, their eyes never appear this dark. It appears that we have a very butch Thayer’s Gull.
And now we know why some birders avoid gulls. The pale eye suggests Herring Gull, but up to 20 percent of Thayer’s Gulls can have a pale iris. The head is pretty round, suggesting Thayer’s. The bill is neither too big or too small, and is very yellow. No orbital ring is visible. What we can see of the underside of the primaries is white, but we can’t see it all. So do we have a robust Thayer’s Gull with a light iris, or a very demure Herring Gull?
All this variation cannot be covered in a standard field guide. For complicated groups like gulls, more detailed identification guides are very useful. Then you can say, “The bird looked similar to the one in the gull guide.”
Winter is the time to study gulls in the Willamette Valley. If you feel a little overwhelmed by some of the fine plumage details described in birding references, consider looking at the shape of the bird. The silhouette above can be identified to species with reasonable certainty. The three things to consider are 1. the shape of the bill (small and slender, but with a noticeable gonydeal bulge), 2. the shape of the head (fairly large with a sloping forehead), and 3. how far the wings extend beyond the tail.
I’m teaching a class on Willamette Valley gulls for Portland Audubon on January 18, 2012, with a local field trip on January 21. We will discuss plumage details, but also the shape of each species. Shape is much more useful when trying to ID distant birds, birds in bad light, or birds in my typically grainy photos. For information on the class, or to register, click here.
Best known as a local gull hotspot, Portland’s Westmoreland Park also hosts good numbers of Cackling Geese in winter. This December has been unusually dry and sunny, so instead of my photos being grainy and dark, they are now overexposed.
Ridgeway’s Cackling Goose (Branta hutchinsii minima) is the smallest race of Cackler, only slightly larger than a Mallard. Their stubby bills and purplish breasts are good field marks. Many individuals also display a prominent white collar.
Of course, you can’t visit Westmoreland in winter without appreciating a Thayer’s Gull. This is such a hard bird to find throughout much of the country, I always stop to enjoy them, despite their local abundance. You can’t see this bird’s eye or bill, but the white underside of the far wing and the amount of white visible on the outermost primary (p10) on the near wing are both good clues to the bird’s ID. (yeah, I’m a bird nerd, and I’m proud.)
In preparation for my shorebirds class for Portland Audubon, I have made several trips to Fernhill Wetlands (Birding Oregon p. 61) in recent weeks. As expected in the Willamette Valley in late summer, species diversity is fairly low, but there is always something to see.
The shorebird class found at least six Stilt Sandpipers on their field trip. This species is a rare migrant in Oregon. I had only seen one individual in Oregon prior to this trip, also at Fernhill.
Two Stilt Sandpipers
Late summer is the ugly duck season, with most birds in their summer alternate, or “eclipse” plumage. I think I know what this little duck is, but I would be interested in your opinions. Leave a comment.
This is a school of young bullheads, I assume Black Bullheads. The young school together while the adult male stays close by to protect them. There were many broods of these little fish in Cattail Marsh.
It’s always nice when similar species pose side by side for direct comparison. These two wigeons, Eurasian on the left, American on the right, were engaged in some synchronized grazing. The female Eurasian Wigeon is a warm brown color, compared to the colder gray/brown tones of the American.
Once considered to be part of the same same species, Thayer’s and Herring Gulls can appear quite similar at first glance.The pattern on the spread wing is very different between the two, but that doesn’t help you with birds at rest.
Here is a Thayer’s Gull on the left, and a Herring Gull on the right. In direct comparison, we can see that the Thayer’s has a slightly darker mantle, rounder head, dark eyes (usually), and a bill that is greenish-gray at the base and yellow at the tip.
Another Herring Gull, probably a female. This bird has a smaller bill and a slightly more rounded head than the bird in the first photo, giving this individual a more Thayer’s-like quality. Note the all-yellow bill, the pale eye, and the light gray mantle.
Here are a few gulls in their second plumage cycle (often referred to as their second year, but that is not always the case). The first two birds are four-cycle gulls. On a four-cycle gull, the second cycle looks much like the first, but the mantle feathers are coming in gray.
Western Gull, second cycle. Note the blackish primaries and tail, the dark gray mantle, the heavy bill, and the fairly extensive mottling on the underparts.
Three-cycle gulls skip the all-brown phase seen on young four-cycle gulls. (So a first cycle Ring-billed Gull has a gray mantle like a second cycle Herring Gull.) The second cycle on a three-cycle gull shows a gray mantle and wing coverts, but the primaries lack the white tips and mirrors seen on an adult.