Gulls bonanza

*Note:  The bird called Belcher's in this entry turned out to be a third-cycle Kelp Gull.  Read this post for rationale.

If you have birded in Panama, then you know that you are a lucky guy if you find any gull species apart of the omnipresent Laughings and the ocassional Franklins'. Well, yesterday a group of birders touched gold in Costa del Este because of the huge mega-flock of gulls and terns present. I saw SIX gull species in three hours, plus lots of very cool birds (many of them were year-birds). I went with Gloriela and our nephew, Michael, to Panama Viejo trying again for the Lesser Black-backed Gull (which was not present). We found again the strange Laughing Gull but this time, the flock of Laughings was accompanied by a full adult Ring-billed Gull somewhat distant. I managed to take a couple of photos for the record. You can see the white unstreaked head and the white spots in the black primaries.

Happy with the finding, we decided to move to Costa del Este, stopping by the western corner (the part closer to the city and to the "corredor sur"), finding a great assembly of birds, including gulls, terns and shorebirds. What immediately caught my attention was a huge dark-backed gull standing alone in the shoreline. It was considerably larger than the Laughing Gulls and than the Ring-billed Gull present (more on that one later), with a bulkier shape and heavy yellow bill tipped in black, followed by red (wider in the lower mandible). Dark eye. Pale yellow(ish) legs. Head and breast completely white, with no streaking. Sides of neck, flanks, belly and upper back white with diffuse dark spots. Back and wings black... blacker in the wings and with a brownish tinge in the back (specially with the bright light). The secondaries had wide white tips. I didn't saw the tail while perched inicially. I thought first it was a Kelp Gull (as I told to Ken Allaire of the Canopy Report who also saw the bird in his way to El Valle), but then the bird took flight, showing a white rump contrasting with the mostly dark tail! It also shows a wide trailing edge on wings (the secondaries tips) and almost no pattern in the underwings (pale with lots of dark markings). Checking my photos I saw a mostly dark tail, with some white on it closer to the rump. I'm still waiting the experts consensus but the tail markings id this bird as a Belcher's Gull (aka Band-tailed Gull), a very rare vagrant to Panama! Here are the photos (only cropped and sharpened, I didn't change color or contrast except otherwise stated):

The last photo shows a complete dark tail, but then you can see some white in the base of it at the first photo.

I overexposed the next photo in the field, then I increased the contrast and did some sharpening at home. It shows better the bill pattern.

In the same site we found this Ring-billed Gull, something between first and second-winter, resting with the Laughings.

While seeing the birds, I almost step on a group of Least Sandpipers accompanied by Collared, Wilson's and Semipalmated Plovers, that were resting under a little mangrove. Those Collareds' are cute, in the words of Gloriela (I'm pretty sure that you will agree).

Eventually, we were joined by Karl and Rosabel Kaufmann and then by Darién Montañez. We decided to move to the mouth of the Matías Hernández river, but the tide was too high so we decided to have lunch and go back later. The plan worked well, because we found a massive flock of gulls at the river. A careful search with the scopes produced some Franklin's Gulls, two first-winter Herring Gulls and a first-winter Lesser Black-backed Gull. We didn't find again the possible Belcher's Gull. The gulls were not alone. Some Black Skimmers (more than twenty) were present too. We notice that there was a single individual with paler underwings, a definitive white tail and broader white trailing edge. May be all this is due to age, or is a different subspecies? Also, lots of shorebirds were in attendance: Marbled Godwits, Willets, Southern Lapwings and Whimbrels. Convinced that the possible Belcher's Gull would not show up, we drove to Panama Viejo again, finding more interesting birds, including two Elegant Terns and the Long-billed Curlew that has been around for a while. I ended the day with seven new year-birds, including one possible Panama life bird. Good numbers for a "trip" right here in the city.