There was a good sized flock (~200) gulls bathing and drinking on the pond and the turnover seemed pretty steady with lots of birds arriving and other departing regularly. Over half of the crowd was Great Black-backed Gulls with most of the remainder being Herring Gulls. It didn't take long for a first cycle (hatched this year) Iceland Gull to appear and then a second! These young gulls were ghostly cream white without a speck of black on them. They had dark eyes and black bills that were substantially thinner and lighter looking than the bills on the Herring and Black-backed Gulls. A third Iceland Gull with a bi-colored bill was a second-cycle bird and a bit lighter than the younger gulls.
There were also a dozen or so Ring-billed Gulls in the mix. Most of these were hanging together in one part of the flock. Surprisingly, it wasn't long before a green winged gull appeared among them! A closer look at the bird showed that both wings had plastic tags on them. The green tags had numbers..."111". Got a couple passable photos just before the sun set and whole flock departed westward.
Here's the details provided by Ken:
Here is some specific information on K111:
Captured 3/15/11 at Price Chopper Plaza, Rt. 20, Worcester, MA
Capture location (GPS): 42.21324, -71.79617
Captured using a rocket net baited with crackers and bread
Sub-adult ring-billed gull
Green wing-tags: K111
Orange leg band: 48
Federal leg band: 1146-31731
Released on site
04/09/11: Orlando's Farm, Brookfield Road, Charlton, MA
This morning I returned to Collins Pond to find the single digit temperatures had predictably frozen the pond solid. So much for waterbird watching here for a while!