LOUISIANA BIRD RECORDS COMMITTEE
REPORT FORM
|
1. English and
Scientific names: Thayer’s Gull, Larus thayeri |
|
2. Number of
individuals, sexes, ages, general plumage (e.g., 2 in alternate plumage): |
|
1 1st winter |
|
3. Locality:
LOUISIANA: Cameron |
|
Specific Locality: Cameron;
nearshore waters of GOM about 1 mile out of
Calcasieu Ship Channel |
|
4. Date(s) when
observed: 01/19/2103 |
|
|
|
5. Time(s) of day
when observed: mid-afternoon |
|
|
|
6. Reporting
observer and address: Paul Conover, Lafayette |
|
|
|
7. Other observers accompanying reporter who also identified
the bird(s): Mac Myers, Dave Patton |
|
|
|
8. Other observers who independently identified the
bird(s): |
|
|
|
9. Light conditions
(position of bird in relation to shade and to direction and amount of light): Good winter sunlight |
|
|
|
10. Optical
equipment (type, power, condition): Zeiss
10s, Nikon D50 w/300mm lens |
|
|
|
11. Distance to
bird(s): 20-30 yards at minimum |
|
|
|
12. Duration of
observation: perhaps 15 minutes |
|
|
|
13. Habitat: ship channel and channel mouth |
|
|
|
14. Behavior of
bird / circumstances of observation (flying, feeding, resting; include and stress habits used in identification; relate
events surrounding observation): Dave
was chumming for gulls to attract jaegers. In the gull melee, Mac noticed a
pale gull which we focused on and photographed during its stay with the
boat. |
|
|
|
15. Description (include only what was actually seen, not what "should" have been seen; include if possible: total length/relative size compared to other familiar species, body bulk, shape, proportions, bill, eye, leg, and plumage characteristics. Stress features that separate it from similar species): A petite pale 1st winter “white-headed gull” with flight feathers paler than in expected local species. Body like a frosted or bleached-out Herring-type gull, thus appearing to belong to the Kumlien’s (Iceland)/Thayer’s Gull group. Relatively solid tail band and contrasting secondary bar, and contrast between darker outer webs and paler inner webs of primaries more suggestive of classic Thayer’s Gull first winter plumage than Kumlien’s. Bill small but not overly delicate, with a noticeable gonydeal angle and a cleaver-shaped culmen profile. Dark, but with the dark-tipped, paler basal 2/3 pattern visibly emerging with close looks, though in small patches only within the original darkly pigmented base. Legs pale pink, not well-seen or studied in field given
circumstances (only visible in flight, when photographing took precedence). Eye
dark. |
|
|
|
16. Voice: |
|
|
|
17. Similar species
(include how they were eliminated by your observation): Several hybrid or putative hybrid
combinations not involving Thayer’s are said to mimic the look of young
Thayer’s. Hybrids/ putative hybrids of
Thayer’s and Kumlien’s are also said to encompass a broad spectrum of looks
from dark to pale, which would include birds such as this. These ID challenges can’t be eliminated. However, in most places a bird such as this
would probably be routinely be assigned to the Thayer’s/Kumlien’s group based
on size and structure, and specifically to Thayer’s based on the relativeness
darkness of its plumage. |
|
|
|
18. Photographs or
tape recordings obtained? (by whom? attached?): yes |
|
|
|
19. Previous
experience with this species: a
few presumed Thayer’s and Thayer’s/Kumlien’s types seen and/or collected over
the years. |
|
|
|
20. Identification aids: (list books, illustrations, other
birders, etc. used in identification): |
|
|
|
a. at time of observation: |
|
|
|
b. after observation: |
|
|
|
21. This
description is written from: memory, study of photos |
|
22. Are you positive of your identification if not, explain: Fairly confident that it is at least in part Thayer’s. I can’t confidently discount a Kumlien’s mix. 23. 12/6/2013 |
|
|
