If you live near the coast and are new to birdwatching, you may be inclined to think that every seabird that you see is a seagull. Gulls are not one bird species, but a wide range of different species, and other birds found in similar locations are not actually gulls at all.
This article will look closely at gulls and the species you might encounter in North America. Then, we will look at terns and skimmers – two other species of birds that can look like seagulls but belong to different groups.
Let’s take a look at birds that look like seagulls…
What Are Seagulls?
Seagulls, or gulls, are seabirds in the family of Laridae.
Keen birders often correct those who use the term “seagulls” because there is no bird called a seagull, and gulls don’t live exclusively by the sea. But semantics aside, whether we are talking about seagulls or gulls, we are talking about this group in the Laridae bird family.
Gulls tend to be medium to large, typically with white or gray coloration, and frequently with black markings on their heads or wings.
They usually have harsh cries or wailing calls and typically have rather long, stout bills and webbed feet. Most gulls nest on the ground and are carnivorous species that eat live food such as fish, mollusks, and crustaceans. They are also often opportunistic scavengers.
Most gulls live most of their lives on or near the coast or islands, rarely venturing far out into the open sea. They can also make their way inland from the coastline – especially to forage in human settlements.
One interesting thing about gulls is that they tend to be very social creatures. They have complex social systems and methods of communication that allow them to work within large, noisy, and densely packed colonies alongside others of their species and sometimes in mixed groups.
Gull species in North America
At least 28 different native or vagrant species of gull can be seen in North America. These are all commonly referred to as seagulls in everyday speech, but birders will call them gulls.
Depending on where you are in North America, you might see:
- Belcher’s Gulls
- Black-headed Gulls
- Black-tailed Gulls
- Bonaparte’s Gulls
- California Gulls
- Common Gulls
- Franklin’s Gulls
- Glaucous Gulls
- Glaucous-winged Gulls
- Gray-hooded Gulls
- Great black-backed Gulls
- Heermann’s Gulls
- Herring Gulls
- Iceland Gulls
- Ivory Gulls
- Kelp Gulls
- Laughing Gulls
- Lesser black-backed Gulls
- Little Gulls
- Ring-billed Gulls
- Ross’s Gulls
- Sabine’s Gulls
- Short-billed Gulls
- Staty-backed Gulls
- Swallow-tailed Gulls
- Western Gulls
- Yellow-footed Gulls
- Yellow-legged Gulls
Identifying different gulls can be challenging since many have few distinctive differences that can be immediately discerned. They can be especially difficult to identify when they are juveniles – and some species can take several years to develop their adult plumage.
Some species also have non-breeding and breeding plumage – so they change in appearance at different times of the year. This can make identification more challenging.
What is more, things are further complicated by the fact that gulls can cross-breed and form hybrids that have the physical characteristics of both species.
The smallest gull is the Little gull, which is around 12 inches long with a wingspan of around 24 inches. The largest is the Great Black-backed gull, which grows to around 30 inches in length and has a wingspan of 60 inches. So, gulls vary quite significantly in size, though they fall within the range between these two birds.
Birds That Look Like Gulls
Gulls all belong to the Laridae family of seabirds and can be confused with other members of this family who are classified within different subgroups: terns, skimmers, and kittiwakes.
Terns are a subgroup of the Laridae, which is divided into seven genera. They are normally found near the sea, rivers, or wetland areas.
Like gulls, most species are gray and white (terns are typically pale gray above and white below), and, like some gulls, they typically have black markings on their heads – usually a black cap. However, a few terns have dark plumage for at least some of the year.
Terns of North America (either native or vagrant visitors) are:
- Aleutian tern
- Arctic tern
- Black tern
- Bridled tern
- Caspian tern
- Common tern
- Elegant tern
- Forster’s tern
- Gull-billed tern
- Large-billed tern
- Least tern
- Roseate tern
- Royal tern
- Sandwich tern
- Sooty tern
- Whiskered tern
- White-winged tern
The largest tern is the Caspian tern, which is 19-22 inches long and weighs 18-25 ounces. The smallest is the Least tern, which is around nine inches long and weighs 1.1-1.6 ounces. All the other terns fall within this range.
Like gulls, terns can sometimes be difficult to differentiate.
What Is the Difference Between a Seagull and a Tern?
Superficially, their coloration can lead people to mistake terns for gulls. However, anatomical differences mean that it is usually fairly easy to see which of these two groups a bird belongs to – even if the specific species is not immediately clear.
Terns are longer-billed, lighter-bodied, and more streamlined than gulls, and their long tails and long, narrow wings make them more streamlined in flight than their gull relatives.
Skimmers are also in the Laridae family. They belong to the genus Rynchops and quite closely resemble terns. They might also be mistaken for gulls on occasion.
The only skimmer species in North America is the Black skimmer, Rychops niger. This bird breeds in North and South America.
It measures 16–20 inches long with a 42–50 inch wingspan. This species ranges from 7.5 to 15.8 ounces in weight. Males average about 12.3 ounces. Smaller females weigh in at around 9 ounces.
Adults have black plumage on their crown, nape, upper body, and white foreheads and underparts. Their wings are black with white on the edge at the back, and their tail is dark gray with white edges.
Adults can look more like some gulls when in non-breeding plumage, with paler brown-gray upper parts and a white nape collar. However, the main characteristics that stand out about these birds are their bill, which is red on the basal half and black on the rest, and their red legs. These birds also have eyes unique among birds, with a brown iris and cat-like vertical pupil.
Kittiwakes are also in the Laridae family. There are two species of kittiwake in North America – the Black-legged kittiwake and the Red-legged kittiwake. The name kittiwake comes from the sound these birds make.
Black-legged kittiwake adults are somewhat larger, roughly 16 inches long, with a wingspan of 35–39 inches. Red-legged kittiwakes are 14–16 inches long with a wingspan of around 33-35 inches.
Kittiwakes can resemble gulls in some ways, such as their white and gray coloration. But, unlike gulls, they are exclusively cliff nesting and will journey much further out to sea. They are also easily identified by listening, rather than just looking, due to their distinctive calls.
Identifying different seabirds can certainly be a challenge. But learning more about the different species of gulls, terns, skimmers, and kittiwakes that you might encounter in your area can help you become a better birdwatcher and learn more about what sets each of these birds apart.