Thursday, January 31, 2013

Some more gulls, and beautiful creatures they are

An adult Ring-billed Gull with gizzard shad. Like a kid in a candy shop. This and the following photos were made last Saturday at Cleveland's East 72nd Street park on Lake Erie. There, the shad pile up in the wake of a power plant's warm water effluvia like scaley locusts in an aquatic wheat field. Unfortunately for the nonnative shad, most die and are consigned to be expelled as gull guano.

At most seasons and in most areas in Ohio, the Ring-billed Gull is, if not the default gull, certainly the most common. This adult in flight shows its clean white tail, and mostly black outer primaries. Of course, that black ring around the bill is a pretty good clue to its identity. The bird is in winter plumage, as indicated by the light brown flecking on the head and neck. As it enters breeding condition in spring, those areas will become bright white.

This is a "second cycle" Ring-billed Gull. When "cycle" is applied to a gull, it indicates a distinct plumage sequence within a series of molts. All gulls take multiple years to attain full adult plumage, which is one of the reasons that they're confusing to identify. Different ages of the same species can look like completely different species.

Ring-billed gulls require about three years to achieve fully adult plumage, as in the birds in the previous two photos. This second cycle animal differs from an adult in its almost entirely black wingtips, and the prominent black terminal tail band.

This is the largest gull that you'll see on Lake Erie, or anywhere in the world. It is a Great Black-backed Gull, and one of these bruisers weighs three times as much as a Ring-billed Gull. The "GBBG" in the photo is a first cycle bird - mostly brown but showing the semblance of a dark mantle on the back. The head and neck are suffused with a dirty brown wash. Note the gargantuan bill.

I suspect that this Great Black-backed Gull is a second cycle bird. Its mantle is darkening up, and shows less of he checkerboard pattern caused by the copious white flecking of a younger bird.

No problem telling an adult Great Black-backed Gull, with its sooty-black upperparts and giant size. These birds are so large that nonbirders sometimes mistake them for Bald Eagles. The individual in this photo would be at least four years old - it takes that many years to achieve fully adult plumage. If it makes it to this stage, it could live for a long time. The oldest known wild bird lived for nearly three decades, and some of the large gull species probably manage to survive for far longer than that.

Big, pale, and ghostly, a Glaucous Gull sticks out like a sore thumb. This is another big boy, second in size and scale only to the Great Black-backed Gull. The Glaucous dwarfs the adult Ring-billed Gull directly behind it. Most of the other birds in the shot are Herring Gulls of various ages. The Herring Gull complex is an interesting group, and we found a real oddball Herringwhatever in this crowd. More on that later.

This is a first cycle Glaucous Gull, with dingy white plumage throughout, no obvious gray mantle differentiation, and a dark eye. Glaucous are among the "white-winged gulls", which includes the Iceland Gull. These Arctic-breeding birds of the far north lack, or mostly lack, dark pigment in the wingtips as can be seen on this bird.

They don't call 'em white-winged gulls for nothing. Glaucous Gulls are always a treat to find. While they are regular along Lake Erie in winter, we don't get very many. They're big, fierce animals capable of domineering the lesser gulls. This is another "four-year" gull - like the Great Black-backed Gull, it takes a Glaucous that long to reach maturity. This was the only of its kind at East 72nd on this day, so I was unable to make images of other age classes. But they look large, white, and cool no matter their age.


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