It’s easy to take seagulls for granted. Dyed-in- the-wool birders cringe when they hear that word, as in, “I saw the cutest little seagull from the ferry last week.” Picture William H. Macy in Fargo, that “Geez” look of desperation. It’s because there is so much diversity in the large and global group of birds called gulls.

As bird groups go, the genus Larus is easy to study, because they are fairly easy to find and to watch. However, many gulls can be hard to identify. Variability is a key word to remember with gull identification. The challenges can be humbling, and certainty elusive. Adult breeding plumages are the most obvious and the best represented in field guides. The larger gulls we encounter on the Vineyard during the nesting season, the herring gull and the great black-backed gull, require four years and an almost constant state of feather molt to acquire the complete adult plumage outfit suitable for attracting a mate.

If you made a point of looking for gulls over the course of an entire year on the Vineyard, you could expect to identify, in descending order of size, great black-backed, herring, Iceland, lesser black-backed and ring-billed gulls, a black-legged Kittiwake, a laughing gull, a Bonaparte’s, and, very possibly, glaucous, black-headed and little gulls as well. There are some other even rarer possibilities, such as a mew gull, a Franklin’s, a Sabine’s gull (three Island records) or a slaty-backed gull, an Asian and sometimes Alaskan species that somehow showed up this winter in at least three different Massachusetts coastal locations, all at about the same time.

Winter boasts the largest variety of gull species on the Vineyard; birds that breed during the summer in the North American mid-west and far north are apt to join our local breeding species where waters do not freeze. Both spring and fall are also excellent times to be on the lookout for gulls moving through or staging for migration.

For recognizing new gulls, experience observing the common species is a requisite foundation for distinguishing the uncommon.