Caspian Tern

The largest tern in the world, Caspian Terns certainly have an air of royalty surrounding them. In terms of terns, they are also the easiest to recognize, owing to their pretty rasps in their calls and the red bill shaped like a fish knife. Present in pretty much every part of the world, Caspians are partial towards saltwater and freshwater habitats. 

They are known to have a longer period of adolescence compared to other species. Months after they are born, the young still rely on their parents. In fact, come late winter, adult Caspian Terns are still seen being followed by a young they had from the previous nesting season. 

Today, we’ll learn about: 

  • Caspian Tern color patterns, songs, and size
  • Caspian Tern behavior, habitat, and diet
  • Caspian Tern life cycle, nesting, and migration range


Caspian Terns Color Pattern

The first thing you notice about Caspian Terns is the black cap on their head. It takes up most of the upper part of their face and some of the back of their head. They also have small, black eyes that are engulfed by the black mask. As a result, it appears as if Caspian Terns are somehow missing eyes. 

Their overall plumage is white in color. Once the black mask ends, you see a white face followed by a white neck, chest, and belly. Even the underpart is white. The underside of their wing is also white on the back of their body and the wing is a whitish-gray. Their tail is also a mixture of white and gray. The outer primary feathers are also black on the underside. Then, the legs are a dark shade of black. As opposed to it, the bills are a brilliant red color. 

There is not much difference between juvenile Caspian Terns and breeding adult terns. However, instead of having a gray-colored back, there are brown or gray markings. Again, even nonbreeding adults are not much different in color patterns. The one thing you do notice is the crown. Instead of the deep black, you are used to, you are suddenly presented with a gray crown. The feathers also appear more unkempt when they are wintering. 

Description And Identification

What could be easier than identifying Caspian Terns? They might be terns and closer to gulls in species, but their body shape certainly reminds one of the ducks. These seabirds are found close to both saltwater and freshwater spaces. If you can’t go to the coast during the right season, your highest chance of seeing them on land is around large lakes and rivers. Instead of trying to find them anywhere on the ground, you just have to keep on looking at the big blue sky. At some point, this species of tern will be seen hovering up in the air as they look for their prey. 

If you happen to see them and are not certain this is the species you are looking for amongst the colony of terns, well, it is easy guesswork to make. Is the bird species bigger than all the other terns in the area? You have your answer. If they have a large bright red bill that almost seems orange under the sunlight? All your questions are answered. Are the wings too large? More than you ever thought a medium-sized species like Terns can have? There you go! You are looking at a Caspian Tern. 

If there is still some confusion left, try to hone in on their calls. Do you hear this raspy call that sounds like a “rraaeee”? Then, you know for certain. 

Caspian Terns appear great in pictures. As a birder, if you are looking for one and do manage to see one, not getting a good picture would be a shame. They fly around a lot so bring a high-quality camera along with your other birding gears. Also, maintain distance from them so as to not ruin their peace. From a distance, you can take as many pictures as you want. You can also simply observe them for hours with your binoculars. 

Caspian Tern Song 

Juvenile and female Caspian Terns during courtship season have this whistling call that sounds like they are saying ree. It is a faint, weak noise that doesn’t last long. From adult Caspian Terns, a roaring, loud and gravelly call is heard. It is a “rraaeu” sound of sorts. The call is either made to contact other birds or to give off warnings to any intruders coming close to the nest. 

Caspian Tern Size

If we compare all terns, it is clear Caspian Terns are the largest. For seabirds, they are quite the heavy body species. They have a large head unlike what we are used to seeing in Terns. Their bill is as straight and pointy as you would expect. The tail is a shallow, forked-shaped one. The wings are long and broad and more pointed than you would think a tern would have. 

Ring-billed Gulls happen to be smaller than them while they tower over Herring Gulls. In length, the longest Caspian Tern is known to have 54 cm. The weight is more than you can even begin to imagine. Yes, the thinnest Caspian is about 530 g. The largest of them are at least 782 g. The wingspan is even broader than one would assume. It is about 128 cm, the longest wingspan for any Tern. 

Caspian Tern Behavior

These kinds of forages keep on flying over the water bodies. They hover and rest in the air until they see a fish hiding in the water. Then, they swoop down to catch their prey. Usually, they stay up high in the air. They are seen at the lower level less often. Mostly, it is when there is prey visible on the water surface that they come down. They are not hesitant about stealing food from other bird species lest the opportunity arises. 

What Caspian Terns Eat

Their diet plan is centered around fish. In whatever locality they have settled in, their concentration is often fixated on a type of fish that has been abandoned. On California coasts, this might be shinier perch. In the Great Lake area, this can be alewife. 

In case of low availability of food, they turn to insects to satisfy their hunger. If even that is not present, they won’t hesitate to eat the eggs of other bird species. Or even the young of other species for that matter. 

If you would like to feed your own birds check out these bird seeds!

Where Caspian Terns Live And Habitat

The habitat of Caspian Terns consists of coastal waters, huge lakes, bays, and beaches. Whether it is freshwater or saltwater, they can adjust easily. They do have a clear preference for protected water bodies. That’s why, you will find them around lakes, lagoons, and rivers more. Rarely do they fly over open seas when they are foraging. 

If they are inland, they will find huge lakes rather than stick around small ponds. Around coasts and islands, they choose open grounds to nest on. 

Range and Migration

Including the Great Lake and other coasts of North America, Caspian Terns reside near large lakes and oceans during the breeding season. In Europe, they are local birds, especially in the Black Sea and Baltic Sea regions. They are also permanent dwellers of Australia, New Zealand, Asia, and Africa. 

The birds from North America end up traveling to the northern region of South America, the southern coasts of North America, and to the west of the Indies. For local Asian and European Terns, the non-breeding season is spent in the tropics of the Old World. The ones in Africa, Australia, and New Zealand refuse to move at all and if they do, they travel the shortest distance possible. 

A recent discovery, in 2016, was made on a nest of Caspian Terns in northwest Alaska. This was at least 1000 miles far from where they have been previously sighted in the region. This overall trend of Terns moving to Alaska has been assigned to a rise in global warming each passing minute. 

Check out the migration patterns of ducks by clicking the link.

Caspian Tern Life Cycle

Caspian Terns have 1 to 3 eggs at most. Rarely are the female terns capable of laying more than 5 eggs. The eggs possess the pale buff coloring familiar to all eggs of terns. The brown or black marking is also present. Both the parents warm the eggs though female Caspians are known to do more of the work. Then, it takes about 20 to 22 days before the eggs are ready to hatch and the young can finally come out. 

Barely days after they have hatched, they become capable enough to leave the nest. If there are no attempts made to disturb the colony, the young can stay in the nest for a long time. They can spend their time there until they have better control of their wings to fly. Both male and female Caspian Terns bring food to their young. Then, at about a month after they are born, the time for their first flight comes. Even after being able to fly, there have been cases where the young have stayed with their parents for 8 months. 


3 years after they are born, the first breeding season comes for Caspian Terns. They usually make their nests in colonial grounds. Sometimes, pairs isolate themselves. Over their colony, male Caspian Terns might do low flights while they carry fish in their bill. The female follows after him. Part of their courtship involves the male feeding the female on the ground. 

For their nest site, they choose dry, bare ground. Usually, debris or driftwood surrounds this nest. Sometimes, they might find dead vegetation and build a nest on top of it. Both members of the couple do their best to make the nest. It helps that it is a shallow depression at most. Debris might be used to line this nest. 

Anatomy of a Caspian Tern

When we say Caspian Terns are heavy body species, we mean really large. Other terns appear too small in front of them. Their big size also doesn’t let them hide away from human eyes. If you are looking for other tern species when they are gathered in an area, your eyes will automatically travel to Caspians. 

For a species with such a large body, they certainly have short and thin legs. The legs are so thin compared to their body that it leaves the question of how it supports them at all. Maybe it makes it a good thing that the species spends most of their time hovering in the air over water bodies. Their bill is a big, straight one. The bill is large enough to easily capture medium-sized fishes and keep them there. The tail is short compared to the body but is overall still a big tail. It is forked at the end. They also have a large heads with small eyes on them. 

Then, there is the wingspan. When the wings are folded, it is hard to tell how big it is. When they spread it though, it takes up an incredible amount of space. 

Final Thoughts

Caspian Terns are a rare species by no means. The population is concentrated in certain areas though, which makes it harder to find them where you live. You will have to make trips to specific locations as a birder if you ever hope to see them. It would be a good idea to make use of location maps when you suspect Caspian Terns are close to you. 

They like roosting with other species of terns and gulls, enjoying the coastal breeze of the ocean and lakes and rivers they find on land. If you want to find them, there are two ways. One is their loud calls and the other is the red bill that is characteristic of Caspian Terns. 

As of now, the population is presumed to be stable. They might even be increasing over the years. All signs point towards the species expanding their range, especially moving to the south of Alaska. Here are also more birds from Alaska that are worth checking out.

There are lots of cool places in the world and one of those places is Yosemite National Park. Or the Rocky National Park.


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Bird Watching Binoculars for Identifying Caspian Tern  

The most common types of bird-watching binoculars for viewing Caspian Terns are 8×21 binoculars and 10×42 binoculars. Bird Watching Academy & Camp sells really nice 8×21 binoculars and 10×42 binoculars. You can view and purchase them here.

Caspian Tern Stickers

Stickers are a great way for you to display your love for bird watching and the Caspian Terns. Here is the sticker pack we sell with a Caspian Terns sticker.

Check out this cool snowy owl patch. Always remember Bird Watching Academy by having a mug!

Bird Feeders For Caspian Tern

There are many types of bird feeders. Bird feeders are a great addition to your backyard. Bird feeders will increase the chances of attracting birds drastically. Both kids and adults will have a great time watching birds eat at these bird feeders. There are a wide variety of bird feeders on the market and it is important to find the best fit for you and your backyard.

Best Bird Houses For Caspian Tern

There are many types of birdhouses. Building a birdhouse is always fun but can be frustrating. These 4 birdhouses have become our favorites. Getting a birdhouse for kids to watch birds grow is always fun. We spent a little extra money on these birdhouses but they have been worth the higher price and look great.

All birds need to clean themselves that’s why you should consider purchasing a birdbath.

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