Saturday, April 4, 2015

Sabine’s Gulls at Lake Lowell

According to Birds of North America Online:

“Sabine’s Gull is an unusual and distinctive arctic gull that breeds at high latitudes but winters in coastal upwelling zones of the Tropics and Subtropics. Its dark gray hood, black bill with yellow tip, and tricolored upperwing consisting of alternating triangles of black, white, and gray make the adults of this species highly identifiable.”

“The Sabine’s Gull is considered an aberrant gull, both morphologically and behaviorally (Brown et al. 1967, Abraham 1986). It is one of only two gulls having a black bill with a yellow tip and a notched tail. It also displays many behavioral characteristics more similar to shorebirds than to gulls (e.g., distraction display, feeding method on mudflats) and others more similar to terns than to gulls (e.g., call, flight, feeding of whole prey directly to female during courtship, development of flight long before chick is fully feathered).”

As an ocean-going bird, Sabine’s Gulls are usually only findable in the lower 48 by taking a pelagic trip off the Pacific cost during their migration, with fall migration typically being much better for finding them close to shore than spring migration.

However, a small handful of them appear to take an overland migration route, since small numbers turn up each year at large lakes and reservoirs across the entire U.S.

ebird range map

eBird map of Sabine’s Gull sightings in the lower 48.

Idaho is the recipient of some of these overland migrants as well, though typically just during fall migration. For a few years, it seemed like the best place to find them in Idaho was Minidoka NWR and Lake Walcott, in south-central Idaho. At the beginning of the year we had penciled in a September trip out there to try to track them down for our state and life lists.

Bar Chart

eBird bar chart of Sabine’s Gull sightings in Idaho.

2014 ended up being a really good year for Sabine’s Gulls in Idaho, with quite a few showing up in locations where they hadn’t been seen before. The first of year for the state was found by John Powell at the McCall Sewage Ponds on August 31, and that was followed by one found at Lake Walcott by Cheryl Huizinga and Pat Weber on September 14. Next up was one found at the Genesee Sewage Lagoon near Moscow by Carl Lundblad on September 19. On the 21st, several started getting reported at Lake Lowell near Nampa, the second time they’d been found at Lake Lowell (the first time was just the year before). We were thrilled to hear about them so close to Boise, and happily postponed our Lake Walcott/Minidoka NWR trip for another year. We made a quick swing by the lower dam at Lake Lowell on the 21st and caught a quick glimpse of one, but nothing satisfying, so we headed back on the 22nd for another try.

Near the dam our first finds were a few more ordinary birds, like this Horned Grebe, a Wilson’s Phalarope, a Spotted Sandpiper, and an Osprey.

IMG_8146

Horned Grebe at Lake Lowell, Canyon County. September 22, 2014.

IMG_8287

Wilson’s Phalarope at Lake Lowell, Canyon County. September 22, 2014.

IMG_8332

Spotted Sandpiper at Lake Lowell, Canyon County. September 22, 2014.

IMG_8627

Osprey at Lake Lowell, Canyon County. September 22, 2014.

IMG_8633

Osprey at Lake Lowell, Canyon County. September 22, 2014.

After knocking out the stuff that was close to shore we started scanning the deeper waters to try to get an eye on the Sabine’s Gulls. Being unfamiliar with this species, I started by scanning the skies to try to find them mixed in with the Ring-billed and California Gulls that frequently fly around the reservoir. That didn’t turn anything up, but after a bit we finally spotted a few interesting looking birds way out deep that looked like they might have the characteristic black “M” shape on the wings that’s a dead giveaway for Sabine’s Gulls.

IMG_8157

Sabine’s Gull at Lake Lowell, Canyon County. September 22, 2014.

We learned right away keeping an eye on these birds that they really behave much more like a tern than most other gulls. They fly low over the water, patrolling long paths across the surface over and over again, skimming or dipping their bills in the water to snag any food items they spot along their path. Next time we look for this species we’ll be sure to watch for this behavior right off the bet to dial in on the birds.

IMG_8175

Sabine’s Gull at Lake Lowell, Canyon County. September 22, 2014.

IMG_8559

Sabine’s Gull at Lake Lowell, Canyon County. September 22, 2014.

Normally birds this far out are too distant to make much of an attempt at identification, but luckily the boldly patterned Sabine’s Gulls really stand out. It’s much easier to pick out a two foot long black and white “M” shape at 500 yards than to try to judge the size of a gonydeal expansion or the color of an iris.

IMG_8570

Sabine’s Gull at Lake Lowell, Canyon County. September 22, 2014.

While the birds started out quite distant, occasionally one of them would swing a wide arc that would carry them closer to the dam where we were photographing from. They move so quick and the light was so dim so our camera really struggled to keep up with them. With some effort we were able to get them in frame, but the focus couldn’t always snap on to the birds before they were too distant again. We stuck it out though, and got a few shots we were a little happier with.

IMG_8449

Sabine’s Gull at Lake Lowell, Canyon County. September 22, 2014.

Notice that most of them are flying away from us by the time the focus locks on. It was still fun to capture their mirror image on the smooth water below.

IMG_8457

Sabine’s Gull at Lake Lowell, Canyon County. September 22, 2014.

IMG_8458

Sabine’s Gull at Lake Lowell, Canyon County. September 22, 2014.

IMG_8459

Sabine’s Gull at Lake Lowell, Canyon County. September 22, 2014.

IMG_8463

Sabine’s Gull at Lake Lowell, Canyon County. September 22, 2014.

We kept noticing as the birds would circle back away from us that they were actually joining up with a fairly large number of them out in the deep water. We kept a careful count several times to try to nail down exactly how many there were. Several others had reported counts as high as 8. Our first count turned up closer to 10, and we counted, re-counted, and counted again to try to be sure we weren’t double counting anything as they zipped by. Our highest count was 15 birds, which I think was probably a slightly conservative estimate of the number of birds out there. We are really confident that there were at least 15 separate birds in the air over the lake at one point, and in among the mix were several more birds that were resting on the water. Some of the resting birds were too distant to confidently identify, but a few of them on the closer edge were definitely Sabine’s Gulls, and it’s likely that several of the further ones were also Sabine’s. Our count of 15 gives us the highest count recorded in the state of Idaho so far! What a fun find!

IMG_8468

Sabine’s Gull at Lake Lowell, Canyon County. September 22, 2014.

IMG_8470

Sabine’s Gull at Lake Lowell, Canyon County. September 22, 2014.

We had several other birds we didn’t photograph, for a total of 17 species seen from the lower dam. Click here to check out our full checklist on eBird.

No comments:

Post a Comment