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|Family||Gulls, Terns and Skimmers - Måger, Terner og Saksnæb - Gaviotas, Charranes y Rayadores (Laridae)|
|Species||Kelp Gull (Larus dominicanus)|
|Locality||Mazatlán, Sinaloa (Sin), Mexico|
Adult bird. Found it on the same beach, Playa Norte, as last year's bird, 2938. Comparing the two there seems to be some indications that they could be the same bird, but I'm not sure.
Last year's bird showed black in various tail feathers, including the out left rectrice which also has a black line on this year's bird. Also the black markings on the tip of the bill and the shape of the nostril seem to be equal, as does the gape line. But the size of the red spot on the lower mandible is different between the two. I'm not sure to how big a degree the birds physical and hormonal conditions will affect the shape and size of this spot. If not, they must be different individuals.
This year's bird seems to be less worn maintaining all the white tips to the primaries and also shows more winter streaking on the back side of the head and neck. Should the two be the same, this makes sense since the present bird is observed one and a half month earlier into the molt cycle than the one last year.
Other gulls in the photos are Ring-billed and Heermann's, plus in photo 9 and 10 two adult Western Gulls. The different back colors between the Westerns and the Kelp were much more obvious in the field than indicated in these photos.
As last year, this year's bird was present when the tide was low. I had visited both on the 4th and the 5th of January without any interesting gulls present. Not even the Westerns. Increasing food availability when the tide is low seems to be a good explanation to why the birds show up.