If you guessed GULLS vs. TERNS, you are correct!
All those birds on the beach – it’s very confusing. To make things a bit clearer, let’s discuss two very common and very similar groups: terns and gulls. What they are NOT are those little birds that run along the edge of the water, or the big ones with the long necks and stilt-like legs. They are what many people call seagulls, a term not used in any good bird book.
There are several different kinds of both gulls and terns that can and do land on our beaches. They will be covered individually at another time. This will be a general discussion of the two groups focusing on how to tell them apart.
Terns and gulls may be confusing for several reasons. They are both on the beach and within the same size range. They are predominantly gray on the top and white beneath. Many have black markings, primarily on their heads and/or wing tips. And in flight, they resemble one another somewhat.
All of them can entertain you by diving from the sky to snag a fish, which these seabirds love, or coming close to investigate what you’ve brought for lunch. While terns eat fish almost exclusively, gulls will eat nearly anything. They’re the ones that beg for human food and scavenge around trash cans and dumps. That big bird in a parking lot is a gull, almost never a tern.
So, how do you differentiate one from the other? While the coloration of gulls and terns is quite similar, there are definite differences in the appearances which you can look for while lolling or walking on the beach. Terns are sleeker and more streamline as you can see from the pictures. They have thinner, sharper, more pointed bills and generally have a more delicate shape. Gulls tend to be heavier set in the body with thicker bills that are hooked at the end.
Gulls take up to two years to obtain their adult plumage. During that early period, they are various degrees of brown as opposed to the adults’ crisp gray and white with black. While terns look somewhat different in their first months, there is much less contrast with the adults than there is with gulls.
The tern stands on shorter legs and is often seen with other terns, roosting on a spit of land, away from humans. The gull, on the other hand, seems to enjoy being near people, although perhaps it’s mostly in hopes of getting some food.
Another distinguishing characteristic is the way the two birds obtain their food. You will see the tern flying over the water often with its head bent sharply down looking for its prey. Then suddenly it will dive straight down from 20 to 50 feet to snatch a fish. In contrast, the gull may swoop down to get a fish, or grab its food while paddling on top of the water. If you spot one of these birds swimming like a duck, it’s almost certainly a gull; terns don’t swim because they don’t have webbed feet like gulls. Gulls also scavenge on land for anything they considers edible; they are omnivores.
In subsequent articles, we will discuss individual terns and gulls but for now, try to distinguish one type from the other as you enjoy the sun and sand. Below are examples of several you can practice on.
Article submitted by: Marcia Hider
Photographs provided by: Charles Moore & Ed Konrad
This blog post is part of a series SIB will publish on a regular basis to feature birds seen in the area, both migratory and permanent residents. When possible we will use photographs taken by our members. Please let us know if you have any special requests of birds you would like to learn more about.