Possible Belcher's Gull [sic] in Costa del Este

Jan Axel Cubilla visited Costa del Este for this afternoon's high high tide and found a strange gull with the thousands of Laughing Gulls just east of the bridge. Originally thought to be a Kelp Gull, when it took flight it showed a lot of black in the tail, which could mean he saw a Belcher's Gull. We'll have to wait for his photos to be sure, but it would be a good idea to visit the area tomorrow for an even higher tide at 4:26 pm.
[The bird in question was proven to be but a subadult Kelp Gull. Apologies]
We waited for the tide to recede and the gulls to reassemble, but could not find the one we were looking for. We did see two or three Herring Gulls, a few Ring-billeds and a young Lesser Black-backed. The beach at Panamá Viejo had two Elegant Terns and a Long-billed Curlew.