Gulls, known colloquially as seagulls, belong to the seabird family Laridae. There are 10 genera of gulls, and they are most closely related to the terns (family Sternidae) and only distantly related to auks, skimmers and even more distantly to waders.
Gull have a worldwide cosmopolitan distribution and breed on every continent. Most gull species are migratory, with birds moving to warmer habitats during the winter. They are medium to large birds, usually gray or white, often with black markings on the head or wings.
These birds are highly adaptable feeders that opportunistically take a wide range of prey, including fish, marine and freshwater invertebrates, rodents, amphibians, reptiles and plant materials. They live in colonies, especially during the mating season. Breeding pairs mostly stick to their own territory and defend it against intruders. Gulls are monogamous and mate for life.
Some species of seagull are considered to be threatened, while others are listed as Least Concern by the IUCN Red List. In the United States, they are protected birds under the Migratory Bird Treaty Act of 1918. In the UK, they are protected under the Wildlife and Countryside Act. They are most affected by climate change and pollution.
Seagull Characteristics
Seagulls are medium to large sized birds. Their size can vary depending on the species; the smallest species, the little gull, has a length of 25 to 30 cm (10 to 12 in) and a weight of 68 to 162 g (23⁄8 to 53⁄4 oz), while the largest species, the great black-backed gull, has a weight of 1.75 kg (3 lb 14 oz) and a length of 76 cm (30 in).
These birds have fairly bulky bodies, with long legs, webbed feet, long wings, and stout bills, which end in a hook. The bill is often yellow in color with a red spot for the larger white-headed species and red, dark red or black in the smaller species. They have a small claw halfway up the lower leg that allows them to roost on high ledges without falling off.
Their bodies are normally covered in white, gray, and sometimes even black plumage, but the color of the head can vary by species, but is usually white or black.
The tails of all but three species are rounded; Sabine’s gull and swallow-tailed gulls have forked tails, and Ross’s gull, has a wedge-shaped tail.
Seagull Lifespan
Seagulls have a pretty long lifespan, with most species living up to 30 years old. Some can live longer though, and some have been known to live to 49 years old!
Seagull Diet
Gulls are mostly carnivorous. They are highly adaptable feeders and take a wide range of prey. The most common foods they eat are fish, marine and freshwater invertebrates, arthropods, insects, rodents, eggs, carrion, offal, reptiles and amphibians. They will also eat plant items and human refuse.
The gull diet has shifted due to overfishing from humans. Research has shown that overfishing has caused gulls to prey more on crustaceans rather than fish such as sardines.
Not only are they adaptable feeders, but they are also adaptable in the way they catch their prey. Gulls feed in the air, on water, or on land. They have only a limited ability to dive below the water to feed on deeper prey, and will much more often hunt for prey when marine hunters, such as orcas and gray whales, drive prey to the surface.
Gulls can be very clever feeders. If they have caught a clam or mussel and cannot open the hard shell, they will fly some distance to find a suitable surface on which to drop shells and crack them open to eat the inside. They have also been known to follow ploughs in fields where they know upturned grubs and other food sources will be plentiful.
Seagulls can drink both fresh and salt water. Most animals are unable to do this, but seagulls have a special pair of glands right above their eyes which is specifically designed to flush the salt from their systems through openings in the bill.
Seagull Behavior
Seagulls live in large colonies with other gulls, either with other gull species or other seabird species. They are vocal communicators that use several distinct calls to demonstrate aggression, identify mating partners, warn the colony of a threat, and resolve a territorial dispute. Baby chicks will also use calls to beg for food from their parents.
Seagulls show ease when swimming, flying, and walking. They are better adapted to walking on land than most other seabirds, and the smaller gulls tend to be more manoeuvrable while walking. Gulls walk in a side to side motion. When flying, they are able to hover and they are also able to take off quickly with little space.
Gulls are very intelligent animals. They display this intelligence when it comes to feeding, as they drop hard-shelled molluscs onto rocks so that they break open so they can eat them. They’ll also stamp their feet in a group to imitate rainfall and trick earthworms to come to the surface. Another example of intelligence is behavior of hovering over bridges in order to absorb raising heat from paved roadways.
Seagull Reproduction
Gulls are monogamous and mate for life. Their breeding season usually occurs in the early springtime after returning to the same site from their annual migration. They return to the same colony, which can vary from just a few pairs of gulls to over a hundred thousand pairs, and may be exclusive to that gull species or shared with other seabird species.
Within their colonies, breeding pairs are very territorial. Gulls will defend their territories from rivals of both sexes through calls and aerial attacks. Most seagulls build their nest in a hollow depression on the ground (and sometimes cliffs) out of vegetation, feathers, rope, and even plastic. The nest is usually located next to a rock, log, or bush to protect it from predators. The building of the nest is part of the pair-bonding.
After mating, the female usually lays three eggs, although it can be less for smaller species. The eggs are usually dark tan to brown or dark olive with dark splotches and scrawl markings. Both the male and the female incubate the eggs, which lasts for around 22 and 26 days and starts after the laying the first egg. This means that the the first two chicks are born close together, and the third chick some time later.
The young gulls are brooded by their parents for about one or two weeks, and often at least one parent remains with them to guard them until they fledge. Both parents take on feeding duties, although early on the male does most of the feeding and the female does of the brooding and guarding of the chicks.
Many young chicks have a mottled brown appearance compared with the more solid colors of the adult plumage. Young gulls form nursery flocks where they will play and learn vital skills for adulthood. Nursery flocks are watched over by a few adult males and these flocks will remain together until the birds are old enough to breed. They reach sexual maturity within a few years.
Seagull Location and Habitat
Gulls are found all over the world and have cosmopolitan distribution. They breed on every continent. Seagulls are mostly found in colonies close to ocean habitats, although some birds will travel far inland in the non-breeding season.
These birds are migratory and move to warmer habitats during the winter. Some migrate very long distances, while others migrate much shorter distances. The biggest impact on their migration behavior is food.
Seagull Conservation Status
Most species of seagull are considered to be Least Concern by the IUCN Red List, although there are some species that are threatened. It is thought the seagull population is declining, and this is likely due to climate change, loss of habitat, pollution and overfishing. Plastic pollution is of most concern, as it is thought that many are regularly consuming plastic waste left by humans on beaches.
In the United States, gulls are protected birds under the Migratory Bird Treaty Act of 1918. In the UK, they are protected under the Wildlife and Countryside Act. This means that in both these countries it is illegal to hunt these birds.
Seagull Predators
Adult seagulls have few predators, although they can occasionally be preyed on by sharks, eagles, falcons and hawks. Young seagulls and gull eggs are most likely to be preyed on, and can be taken by raccoons, minks, foxes, cats, and birds of prey.
To scare off predators, groups of seagulls will go after the predator and use their feet and wings to bat them away.
Seagull FAQ’s
Are seagulls and gulls the same animal?
Seagulls and gulls are the same. In fact, the term “seagull” is a colloquial term. It is not used by ornithologists and biologists.
Why can seagulls drink both freshwater and saltwater?
Seagulls can drink both freshwater and saltwater because they have special pair of glands right above their eyes which is specifically designed to flush the salt from their systems through openings in the bill, which helps to assist the kidneys in maintaining electrolyte balance.
Can seagulls hurt humans?
Seagulls are very strong birds, and have been known to hurt both humans and animals. While they are not aggressive animals, they can “attack” humans when trying to take food. They take our food because they have lost their fear of humans, and have realised that we are easy source of food!
Are seagulls migratory?
Gulls are migratory. They move to warmer areas during the winter. The distance they travel depends on the species — some travel very far, while others just disperse around the breeding grounds.
Seagull Species
Gulls belong to the family Laridae. There are 54 species of gull, broken down into 10 genera, as laid out below. Some species have subspecies.
Genus: Larus
- Pacific gull, Larus pacificus
- Belcher’s gull, Larus belcheri
- Olrog’s gull, Larus atlanticus
- Black-tailed gull, Larus crassirostris
- Heermann’s gull, Larus heermanni
- Common gull or mew gull, Larus canus
- Short-billed gull, Larus brachyrhynchus
- Ring-billed gull, Larus delawarensis
- California gull, Larus californicus
- Great black-backed gull, Larus marinus
- Kelp gull, Larus dominicanus
- Cape gull, Larus dominicanus vetula
- Glaucous-winged gull, Larus glaucescens
- Western gull, Larus occidentalis
- Yellow-footed gull, Larus livens
- Glaucous gull, Larus hyperboreus
- Iceland gull, Larus glaucoides
- Kumlien’s gull, Larus glaucoides kumlieni
- Thayer’s gull, Larus glaucoides thayeri
- European herring gull, Larus argentatus
- American herring gull, Larus smithsonianus
- Caspian gull, Larus cachinnans
- Yellow-legged gull, Larus michahellis
- East Siberian herring gull, Larus vegae
- Armenian gull, Larus armenicus
- Slaty-backed gull, Larus schistisagus
- Lesser black-backed gull, Larus fuscus
- Heuglin’s gull, Larus fuscus heuglini
Genus: Ichthyaetus
- White-eyed gull, Ichthyaetus leucophthalmus
- Sooty gull, Ichthyaetus hemprichii
- Great black-headed gull or Pallas’s gull, Ichthyaetus ichthyaetus
- Audouin’s gull, Ichthyaetus audouinii
- Mediterranean gull, Ichthyaetus melanocephalus
- Relict gull, Ichthyaetus relictus
Genus: Leucophaeus
- Dolphin gull, Leucophaeus scoresbii
- Laughing gull, Leucophaeus atricilla
- Franklin’s gull, Leucophaeus pipixcan
- Lava gull, Leucophaeus fuliginosus
- Gray gull, Leucophaeus modestus
Genus: Chroicocephalus
- Silver gull, Chroicocephalus novaehollandiae
- Red-billed gull, Chroicocephalus novaehollandiae scopulinus
- Huahine gull, Chroicocephalus utunui (extinct)
- Hartlaub’s gull, Chroicocephalus hartlaubii
- Brown-hooded gull, Chroicocephalus maculipennis
- Gray-headed gull, Chroicocephalus cirrocephalus
- Andean gull, Chroicocephalus serranus
- Black-billed gull, Chroicocephalus bulleri
- Brown-headed gull, Chroicocephalus brunnicephalus
- Black-headed gull, Chroicocephalus ridibundus
- Slender-billed gull, Chroicocephalus genei
- Bonaparte’s gull, Chroicocephalus philadelphia
- Saunders’s gull, Chroicocephalus saundersi
Genus: Hydrocoloeus
- Little gull, Hydrocoloeus minutus
Genus: Rhodostethia
- Ross’s gull, Rhodostethia rosea
Genus: Rissa
- Black-legged kittiwake, Rissa tridactyla
- Red-legged kittiwake, Rissa brevirostris
Genus: Pagophila
- Ivory gull, Pagophila eburnea
Genus: Xema
- Sabine’s gull, Xema sabini
Genus: Creagrus
- Swallow-tailed gull, Creagrus furcatus
Here are some facts about some of the most common species of seagull.
Little Gull
The little gull (Hydrocoloeus minutus) is the smallest gull species. It has a length of 25 to 30 cm (10 to 12 in), a wingspan of 61 to 78 cm (24 to 30.5 in), and a weight of 68 to 162 g (23⁄8 to 53⁄4 oz). It is pale gray in its breeding plumage with a black hood, dark underwings and often a pinkish flush on the breast. In winter, the head goes white apart from a darker cap and eye-spot. The bill is thin and black and the legs dark red.
These gulls breed in northern Europe and across the Palearctic. They are migratory, wintering on coasts in western Europe, the Mediterranean and, in small numbers, the northeast United States.
The little gull is listed as Least Concern on the IUCN Red List.
Great Black-Backed Gull
The great black-backed gull (Larus marinus) is the largest gull species. It is 64 to 79 cm (25 to 31 in) long with a 1.5 to 1.7 m (4 ft 11 in to 5 ft 7 in) wingspan and a body weight of 0.75 to 2.3 kg (1 lb 10 oz to 5 lb 1 oz). It has a white head, neck and underparts, dark gray wings and back, pink legs and yellow bill.
These gulls breed on the European and North American coasts and islands of the North Atlantic. They are listed as Least Concern on the IUCN Red List.
European Herring Gull
The European herring gull (Larus argentatus) breeds across Northern Europe, Western Europe, Central Europe, Eastern Europe, Scandinavia, and the Baltic states. It is a large gull, measuring up to 66 cm (26 in) long and weighing between 1,050 and 1,525 g (2.315 and 3.362 lb).
These gulls have a light gray back and upper wings and white head and underparts. The wingtips are black with white spots known as “mirrors”. Their bill is yellow with a red spot.
The European herring gull is commonly found in human-adapted areas along the shores of Western Europe, where they are scavengers. They are currently listed as Least Concern on the IUCN Red List.
Black-Headed Gull
The black-headed gull (Chroicocephalus ridibundus) breeds in much of the Palearctic including Europe and also in coastal eastern Canada. It is mostly migratory and winters further south. It is a small gull that measures between 37 and 44 cm (15 and 17 in) long with a 94 to 110 cm (37 to 43 in) wingspan and weighs from 190 to 400 g (6.7 to 14.1 oz).
These gulls have a chocolate-brown head, a pale gray body, black tips to the primary wing feathers, and red bill and legs. It is a noisy species, especially in colonies.
The eggs of the black-headed gull are considered a delicacy by some in the UK and are eaten hard boiled. The collection of black-headed gull eggs is heavily regulated by the UK government.
The black-headed gull is listed as Least Concern on the IUCN Red List.
Common Gull
The common gull (Larus canus), also known as the sea mew, breeds in the Palearctic, northern Europe, and migrates further south in the winter. It is medium in size, measuring between 40 and 46 cm (16 and 18 in) long. Its body is gray above and white below, and its legs are yellow in breeding season. It has a shorter, tapered bill, which is a greenish shade of yellow.
There are three subspecies of the common gull — the nominate species, and the Russian common gull and the Kamchatka gull. The common gull is currently listed as Least Concern on the IUCN Red List.
Red-Billed Gull
The red-billed gull (Chroicocephalus novaehollandiae scopulinus), also known as tarāpunga, is native to New Zealand. It is usually considered a subspecies of the silver gull (Chroicocephalus novaehollandiae).
This gull is small, and gets its name from its all-red bill. It also red eye ring, red legs and feet, pale gray wings with black wingtips. The rest of the body and tail are white.
The population of the red-billed gull is estimated to be around 500,000 individuals.
Black-Tailed Gull
The black-tailed gull (Larus crassirostris) is found in East Asia, along the coastlines of the East China Sea, Japan, Manchuria and the Kuril Islands. It is a medium sized gull, measuring around 46 cm (19 in) in length, with a wingspan of 126 to 128 cm (49.6 to 50.3 in).
As its name suggests, it has a black tail. It has yellow legs and a red and black spot at the end of its bill. Its underside is white, with the upper plumage gray.
The black-tailed gull is currently listed as Least Concern on the IUCN Red List.
Laughing Gull
The laughing gull (Leucophaeus atricilla) is found in North and South America, breeding on the Atlantic coast of North America, the Caribbean, and northern South America. It has two subspecies. It is named for its laugh-like call.
This gull measures between 36 and 41 cm (14 and 16 in) long and has a wingspan of 98 and 110 cm (39 and 43 in). It weighs between 203 and 371g (7.2 and 13.1 oz). The laughing gull is white apart from its back and wings which are dark grey. It also has a black head.
The laughing gull is listed as Least Concern on the IUCN Red List.
Yellow-Legged Gull
The yellow-legged gull (Larus michahellis) is found in Europe, the Middle East and North Africa. As its name suggests, it has yellow legs and a gray back. This bird is large in size, measuring from 52 to 68 cm (20 to 27 in) in total length. They have a wingspan between 120 to 155 cm (47 to 61 in) and weigh from 550 to 1,600 g (1.21 to 3.53 lb).
The yellow-legged gull has two subspecies, L. m. michahellis and L. m. atlantis. They are similar to herring gulls, lesser black-backed gulls and great black-backed gulls. They are listed as Least Concern on the IUCN Red List.
Mediterranean Gull
The Mediterranean gull (Ichthyaetus melanocephalus) is mainly found around the Black Sea and in central Turkey. In the winter, it migrates to Mediterranean and Atlantic coasts. It is a small gull, with a white plumage and a pale gray mantle. It has a black head and a dark red bill.
The Mediterranean gull is currently listed as Least Concern on the IUCN Red List.
Western Gull
The western gull (Larus occidentalis) is found on the west coast of North America, ranging from British Columbia, Canada to Baja California, Mexico. It is a large gull that can measure 55 to 68 cm (22 to 27 in) in total length, with a wingspan between 130 and 144 cm (51 and 57 in). It weighs 800 to 1,400 g (1.8 to 3.1 lb).
This seagull has a white head and body, with a dark gray mantle. It has a large and bulbous-tipped yellow bill with a red spot. There are two subspecies of the western gull, which differ in their appearance.
The western gull is often seen around marinas, beaches and parks, trying to steal human food. They are currently listed as Least Concern on the IUCN Red List
Glaucous Gull
The glaucous gull (Larus hyperboreus) is the second largest gull in the world, measuring between 55 and 77 cm (22 and 30 in) in length with a wingspan of between 132 and 170 cm (52 and 67 in). It can weigh from 960 to 2,700 g (2.12 to 5.95 lb).
This bird breeds in Arctic regions of the Northern Hemisphere and winters south to shores of the Holarctic. It is very pale in color, with no black on either the wings or the tail.
Their are four subspecies of the glaucous gull. They are currently listed as Least Concern on the IUCN Red List.
