31-B-2018 Laughing Gull

STATUS
In 1st Round
HOW MANY OBSERVED?
1
DATE SIGHTING OCCURRED
DATE REPORT PREPARED
REPORTER
Ross Silcock
OTHER OBSERVERS
Michael Hogg- first noticed the bird and suggested it was a Laughing Gull.
LOCALITY OF OBSERVATION
Lake Walcott Spillway, Minidoka County, Idaho, US
HABITAT WHERE THE BIRD WAS OBSERVED
tailrace of Minidoka Dam; water forming rapids over rocky area.
SIGHTING DURATION, CONDITIONS, and EQUIPMENT USED
Observed the bird for about 30 minutes. Weather was calm, bright sun, light was over our right shoulders but a bit harsh. We were parked along the paved road around 970 yards (measured on Google Earth) straight northwest of the dam face and, on the same line, 250 yards northwest of the bird, which was perched on a rock. I used a Nikon 90 mm scope and a 400 mm lens on a Nikon SLR camera to get the photos.
DID YOU TAKE NOTES?
No, not at all
DID YOU CONSULT A FIELD GUIDE OR OTHER REFERENCE WORK?
Yes, another day after the observation
WHICH GUIDE(S) OR REFERENCE(S): DID YOU CONSULT?
National Geographic. We discussed the field marks and ID during the sighting, but concentrated on getting photos. I looked at National Geographic field guide (7th edition) when I got home, September 6.
DESCRIPTION OF THE BIRD(s)
Among a large number of Franklin's Gulls for comparison, Michael noticed a gull perched on a small rock in the rapids that appeared to be afraid to get into the fast-moving water (unlike the Franklin's). Using the scope, we could see a gull that appeared a bit larger than the Franklin's nearby, with a noticeably longer, slightly droopy bill. The folded primaries were black, with a string of white spots, presumably the white primary tips more visible in flight. The head retained a shadow of the black hood, placed further forward than the "back half" of the head location on most of the Franklin's. We aged the bird as an adult molting from alternate to basic. Legs were dark, almost black. There was a prominent eye crescent at the rear edge of the eye.
BEHAVIOR OF THE BIRD(s)
During our 30-minute observation, the bird was trying to figure out how to get into the water, and was turning around continuously, peering at water, but finally flew, at which point we lost it among the Franklin's Gulls present.
HOW AND WHEN DID YOU POSITIVELY IDENTIFY THE BIRD, AND WHAT CLINCHED THE IDENTIFICATION FOR YOU?
We were convinced it was a Laughing Gull while it was under observation , and the photos confirmed our thinking. Main features we used for ID were (1) black primaries which extended past the tail and had a row of white spots, (2) the bill which was about the same length as the head from bill base to nape, (3) remains of the black hood, now brownish-looking, and its larger extent than Franklin's.
HOW DID YOU ELIMINATE SIMILAR SPECIES? WHAT WERE THEY?
Bird was larger than Franklin's, location of molting hood was more extensive and further forward than on Franklin's, bill was longer with a slight but noticeable droop than Franklin's, In my mind, most convincing were the black primaries extending past the tail with the series of quite visible white spots, indicative of an adult Laughing Gull and not present in any Franklin's plumage. The one photo I got that showed the open upper wing showed that the latter was overall dark,
WHAT IS YOUR EXPERIENCE WITH THIS (AND SIMILAR) SPECIES?
I have seen thousands of Laughing Gulls on the Texas coast in winter, vagrants in both Iowa and Nebraska, and thousands of Franklin's Gulls in both states.
DESCRIBE YOUR GENERAL BIRDING EXPERIENCE
I am an active birder, retired, mostly in Nebraska. I am currently on the Nebraska Ornithologists Union Records Committee and compile Seasonal Reports for Nebraska Bird Review and co-write the Southern Great Plains section of American Birds with Joseph Grzybowski. Of course I am not as sharp (hearing, mostly) as I once was at age 73, but still, I think, one of Nebraska's top 10 birders.
WERE PHOTO(S), VIDEO, AND/OR AUDIO OBTAINED FROM THIS SIGHTING?
Photo
SUPPORTING IMAGES