LOUISIANA BIRD RECORDS COMMITTEE

REPORT FORM

1. English and Scientific names: Great Black-backed Gull, Larus marinus

2. Number of individuals, sexes, ages, general plumage (e.g., 2 in alternate plumage): One adult

3. Locality: Parish: __Terrebonne __________________________

Specific Locality: __ Whiskey Island, Isles Dernieres __________________________

4. Date(s) when observed: 17 December 2013

5. Time(s) of day when observed: 1440-1510 CST

6. Reporting observer and address: Rob Dobbs, Lafayette, LA 70503

7. Other observers accompanying reporter who also identified the bird(s): NA

8. Other observers who independently identified the bird(s): NA

9. Light conditions (position of bird in relation to shade and to direction and amount of light): Bright sunlight, generally at a bad angle (bird to W/SW). Briefly gained a better angle (S) before bird flew.

10. Optical equipment (type, power, condition): Swarovski spotting scope

11. Distance to bird(s): 100-150 m

12. Duration of observation: 20 min

13. Habitat: Barrier island beach

14. Behavior of bird / circumstances of observation (flying, feeding, resting; include and stress habits used in identification; relate events surrounding observation): Resting, in company of Ring-billed and Laughing gulls. Also observed in flight as bird moved between resting sites approximately 100 m apart.

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 massive, adult white-headed gull with dark mantle/wings. Appeared to be approximately 50 % larger/heavier than Ring-billed Gull and > 50 % larger/heavier than Laughing Gull (direct comparisons, standing next to both species). Very large bill with notable gonydeal expansion. Bill yellow with some red near gonys; little (no?) black visible in bill. Slaty-blackish upperparts. Flesh-pink legs. In flight, large white tip on P10 and large white window in P9.

16. Voice: Not vocal

17. Similar species (include how they were eliminated by your observation): Lesser Black-backed Gull and Kelp Gull are smaller than Herring Gull, and thus significantly smaller than Great Black-backed Gull. Adult Lesser Black-backed and Kelp gulls also have yellow and yellowish-greenish legs, respectively. Kelp x Herring Gull hybrids may be dark-backed and could have flesh-colored legs (although those documented by Dittmann and Cardiff 2005 had yellow, greenish, or grayish-green legs), but would not be larger than Herring Gull. Based on direct comparisons with adjacent (standing) Ring-billed and Laughing gulls (photos attached), the bird in question appears to be significantly larger than Herring Gull. Lesser Black-backed, Kelp, and Kelp x Herring gulls also show less white in wingtip, showing smallish white window in P10 (not large tip). Western and Slaty-backed gulls have pink legs and could look very dark-backed, especially when back-lit, but have limited white in P9 and a white window (not a large white tip) in P10.

18. Photographs or tape recordings obtained? (by whom? attached?): Photos by Rob Dobbs, attached

19. Previous experience with this species: Little experience, on the east coast

20. Identification aids: (list books, illustrations, other birders, etc. used in identification):

a. at time of observation: NA

b. after observation: Howell and Dunn 2007, Gulls of the Americas; Dittmann and Cardiff 2005, The “Chandeleur” Gull (Birding article)

21. This description is written from: __X___ notes made during the observation (_____notes attached?);_____notes made after the observation (date:_____); _____memory.

22. Are you positive of your identification if not, explain: Confident in ID… wingtip pattern and size should rule out other candidates.

23. Date:_9 January 2014_________Time:_0800 CST______