Seabirds are flying (and in some cases non-flying) vertebrates that have evolved to live alongside oceans, coasts, and other aquatic environments. Compared with many land birds, they often show more subdued plumage tones and possess specialized salt-removing glands that help them cope with a salty diet. Below you’ll find a clear overview of what seabirds are, the traits that define them, and a practical guide to well-known seabird groups.
What Are Seabirds?
Seabirds are birds adapted to marine and coastal habitats such as beaches, rocky shorelines, estuaries, wetlands, lagoons, and sometimes inland waters connected to marine food chains. Many species travel long distances and may migrate between continents after the breeding season. Because breeding opportunities are often concentrated in safe nesting areas, a large proportion of seabirds nest in colonies—sometimes in numbers that can reach hundreds of thousands (or more) in a single location.
From an evolutionary perspective, seabird lineages expanded and diversified over long geological periods as they adapted—both physically and physiologically—to feeding in or near the ocean. These adaptations include salt management, waterproof feathers, specialized wing shapes, and hunting strategies that match their preferred prey and habitat.
Characteristics of Seabirds
1) Wing shape and flight style
Pelagic gliders (open-ocean fliers) often have long, narrow wings that allow efficient soaring over vast distances.
Diving birds tend to have shorter wings that improve maneuverability underwater, even if that makes flying more energy-demanding.
2) Plumage built for water and weather
Many seabirds have dense, water-resistant feathers that help them stay warm and dry in windy, cold marine conditions.
Plumage is often less bright than that of many land birds, commonly featuring whites, grays, browns, and blacks that support camouflage and reduce visibility to predators.
3) Salt management
Seabirds commonly have salt glands above the eyes (supraorbital glands) that filter excess salt from their bloodstream, allowing them to drink seawater and eat salty prey.
4) Webbed feet and aquatic movement
Many seabirds have webbed feet that improve paddling on the surface and provide propulsion while diving.
5) Diverse feeding strategies
Surface feeding: picking prey from the water’s surface.
Pursuit diving: swimming underwater to chase fish or invertebrates.
Plunge diving: dropping from the air to snatch prey beneath the surface.
Common Seabird Groups (Names and Traits)
Albatrosses (Family: Diomedeidae)
Albatrosses are large oceanic birds best known for their impressive wingspans—among the greatest of any living flying bird. They spend much of their lives over open water, gliding efficiently on ocean winds. Their diet commonly includes squid, fish, and krill. Many species form long-term pair bonds, returning to breeding sites to raise chicks with strong cooperation between partners.
Cormorants (Family: Phalacrocoracidae)
Cormorants are skilled fish hunters that capture prey by diving and pursuing it underwater. Some species coordinate in groups, diving together to concentrate fish schools and improve hunting success. Their feathers are often less waterproof than those of many other seabirds, which can help reduce buoyancy and allow deeper, longer dives—though it also means they frequently spread their wings to dry.
Terns (Family: Sternidae)
Terns typically live near coasts, rivers, and wetlands. They are streamlined birds with relatively short legs, long pointed bills, and often forked tails. Many species have pale gray-and-white plumage. Terns are famous for their precise feeding technique: hovering or flying over the water and then diving to catch small fish. Some species also eat insects, especially in freshwater habitats.
Eiders (Genus: Somateria)
Eiders are sea ducks adapted to cold coastal regions. Different species occupy distinct ranges across the Arctic and subarctic, often along rocky shorelines and island coasts. They feed mainly on marine invertebrates—such as mollusks and crustaceans—by diving. Eiders are also well known for their insulating down, which helps them endure harsh climates during nesting and incubation.
Frigatebirds (Family: Fregatidae)
Frigatebirds are tropical seabirds built for soaring, with long wings and a remarkably light body that allows them to glide for long periods over warm seas. Rather than diving deeply, they often snatch prey near the surface. Males are famous for courtship displays that include inflating a bright red throat pouch to attract females. Their flight agility is exceptional, making them striking to watch in coastal skies.
Auks, Puffins, and Guillemots (Family: Alcidae)
Alcids are northern-hemisphere seabirds that “fly” underwater using their wings, making them excellent swimmers and divers. Although they may resemble penguins in shape and behavior, they are not closely related. Their wings are short, requiring rapid wingbeats in the air, but they are highly efficient for underwater propulsion. This family includes puffins, guillemots, murres, and other cliff-nesting seabirds known for dense coastal breeding colonies.
Herons (Family: Ardeidae)
Herons are long-legged wading birds found in marshes, lakes, estuaries, and other shallow waters where they hunt fish, crustaceans, amphibians, and aquatic insects. Many species stand motionless for long periods before striking quickly with a spear-like bill. While some herons gather in breeding colonies, they are often solitary feeders and maintain space while hunting.
Gulls (Family: Laridae)
Gulls are among the most recognizable coastal birds, ranging widely across shorelines, ports, and even inland areas. Their plumage typically includes combinations of white, gray, and black, often with distinctive wing patterns. Gulls are adaptable feeders with strong bills, eating fish, invertebrates, and a variety of other foods depending on local availability. Their size and appearance vary widely, reflecting the diversity within the family.
Pelicans (Genus: Pelecanus)
Pelicans are large waterbirds instantly recognized by their long bill and expandable throat pouch. They use the pouch to scoop fish and water, then drain the water before swallowing prey. Many pelicans are highly social, feeding in groups and nesting in colonies. Their coordinated behavior can make them very efficient hunters in productive coastal and estuarine waters.
Penguins (Family: Spheniscidae)
Penguins are seabirds that do not fly, living almost entirely in the Southern Hemisphere. Their wings have evolved into flippers, optimized for powerful swimming and deep diving. Penguins also have dense bones and specialized insulation to retain body heat in cold waters. They are agile underwater predators, feeding mainly on fish, squid, and krill, and many species breed in large colonies where they rely on vocal and visual cues to recognize mates and chicks.
Why Seabirds Matter in Marine Ecosystems
Seabirds help maintain balance in coastal and ocean food webs by regulating prey populations and serving as indicators of marine health. Changes in seabird numbers, breeding success, or migration timing can reflect shifts in ocean conditions, food availability, and habitat quality.
Quick Tips for Identifying Seabirds
Look for these clues
Wing shape: long and narrow (gliders) vs. short and compact (divers).
Feet: webbed feet are common in swimmers and divers.
Behavior: plunge-diving, surface feeding, or wading in shallow water.
Habitat: open ocean, coastal cliffs, sandy beaches, marshes, or estuaries.
Seabird Names at a Glance
Albatrosses (Diomedeidae)
Cormorants (Phalacrocoracidae)
Terns (Sternidae)
Eiders (Somateria spp.)
Frigatebirds (Fregatidae)
Auks/Puffins/Guillemots (Alcidae)
Herons (Ardeidae)
Gulls (Laridae)
Pelicans (Pelecanus spp.)
Penguins (Spheniscidae)
