Verification of Unusual
Rec. # 2011-08
|Scientific name:||Larus occidentalis|
|Date:||11 January 2011 (also seen and photographed by Norman Jenson on 22 January 2011)|
|Time:||around 11:30 AM|
|Length of time observed:||approximately 5 minutes|
|Location:||In the Bountiful Landfill|
|Distance to bird:||200 yards?|
|Optical equipment:||Nikon Premier 10x42 binoculars and Swarovski 80mm scope with 20x60 eyepiece|
|Light Conditions:||Good - I was able to make out colors very well.|
|Description: Size of bird:|
|(Description:) Basic Shape:|
|(Description:) Overall Pattern:|
|(Description:) Bill Type:|
Field Marks and
I drove up to the gate at Bountiful Landfill and parked on the side of the road outside the gate. Through binoculars, I immediately noticed a dark mantled gull circling in the swarm of gulls near the active portion of the landfill. It had a mantle similar in shade to the Lesser Black-backed adult I'd seen a few minutes earlier (roosting on the frozen pond to the south of the landfill) with dark brown coverts, white rump, black tail, and black wing tips. I thought it was going to be a subadult Lesser Black-backed but it was immediately obvious upon landing among Herring Gulls that it was a larger bulkier bird. I put the scope on the window mount and immediately recognized it as a Western Gull when I saw the large bulky bill, head shape, dark mantle, etc. I then attempted to shoot video through the spotting scope and got two poor quality videos before the bird landed out of site. I did not see the bird again before leaving.
This description was written from memory as well as from photo taken 23 January by Norman Jenson and my video clips.
2nd winter large gull with dark gray mantle, dark brown wing coverts, pink legs, black wing tips and black tail.
-The body, head and nape were marked irregularly with brownish smudging on a whitish background.
-The bill is heavy and swells noticably at the gonys making it look bulbous. It appeared mostly dark at a distance with a paling base. In the scope, and in the photo, I could see an extensively pink based bill with black tip. The extreme tip of the bill is pale but I was not able to discern that in the scope view. The pink base and black tip are not sharply demarcated like on a 1W Glaucous Gull, rather the pink blended into the black with some mottling of lighter and darker.
-Head rounded and domed above the eye, not flat-crowned like a Herring Gull. The eye is set more centrally in the head (further from the bill) than Herring or Thayer's and the eye appears small.
-Mantle dark gray, close to Lesser Black-backed, perhaps not quite as dark, and obviously darker than Glaucous-winged Gull.
-Lesser and median wing coverts unmarked dark brown and not contrasting noticably darker than mantle. Greater coverts a bit paler and slightly checkered with lighter and darker.
-Primaries solidly black with outer primaries black on both webs and lacking pale inner primary panel (visible in vodeo by pausing when the bird is in flight) typical of Herring Gull
-Secondaries black with white tips creating white trailing edge to inner wing. Secondaries were visible when standing on ground and in photo (secondary skirt).
-Rump whitish with moderate amoung of dark barring, contrasting fairly strongly with mantle and tail in flight.
-Legs pink, somewhat darker than Herring Gull.
-Primary extension about like Herring Gull
-Body appeared bulkier than Herring Gull
|Song or call & method of delivery:||N/A|
|Behavior:||Alternately roosting and flying around in the swarm of other gulls. Although I did not notice it in the field it had an injured left leg. In one of the video clips it can be seen holding its left foot up when standing and it does not use the left leg to spring into the air when it takes flight.|
were they eliminated:
The dark gray mantle and black wings eliminate most large gulls species. Slaty-backed,
Lesser Black-backed, Yellow-footed, Western x Glaucous-winged and possibly Great
Black-backed and Kelp are contenders for confusion.
-Great Black-backed is much darker on the mantle, has much heavier bill, paler pink legs, and is huge-even small dainty GBBGs are larger than this individual.
-Kelp Gull has much darker blackish mantle that contrasts more with wing coverts, heavier more bulb-tipped bill, and greenish or yellowish legs.
-Slaty-backed has a much darker mantle with paler wing coverts creating much more contrast between coverts and mantle, more slender bill with less obvious gonydeal bulge, pale inner primary panel, and typically a yellow iris in 2nd winter.
-Lesser Black-backed is smaller with much more slender body, shorter and thinner bill, and longer primary extension beyond tail.
-Glaucous-winged x Western would have paler brown primaries than this individual, not black, paler brown (again not black) tail, shorter primary extension beyond tail, and paler mantle somewhat intermediate between the species.
-Yellow-footed Gull has longer heavier bill with more bulbous tip. Yellow-footed is also more advanced in plumage maturation with more extensive gray above, including wing coverts, unmarked white rump (fairly extensive dark barring is visible on the rump in the video clip, better if you stop it at the right place. I had the best success with Windows Media Player), and cleaner white underparts lacking dark smudging.
this & similar species:
|I've been studying gulls fairly seriously for about ten years and see thousands of Ring-billed and Californian annually, as well as hundreds of Herrings and a few Thayer's. I've seen a few Western Gulls in CA, two in Idaho and one in Utah.|
|References consulted:||Peterson Gulls of North America (Howell and Dunn)|
|Observer's address:||4125 Beaver Springs Rd., Island Park, ID 83429|
|Observer's e-mail address:||email@example.com|
|Other observers who independently identified this bird:||
This individual was photographed at Farmington Bay by Norman
Jenson on 22 January 2011 (see photo below) and was also photographed at
Farmington Bay by Cameron Cox on 20 January 2011 (Cameron stated in his post to
Birdtalk@utahbirds.org that this
individual was injured and limping noticeably so it would seem to be the same
bird). I did not obtain permission to use Cameron's photos but they are posted
to a public web site (Flickr) at:
|Date prepared:||30 January 2011|
Two video clips shot at Bountiful Landfill on 11 January 2011 by
Cliff Weisse are posted at:
|Additional_Comments:||These two photos were taken by Norman Jenson at Farmington Bay on 22 January 2011. I requested and received permission to use this photo from Norman.|