There are several types of birds that are specialized to eat primarily fish or other aquatic animals. Birds that are dependent on fish and other aquatic prey are often referred to as “fish-eating birds” or “piscivorous birds.” Some examples of birds that rely heavily on fish in their diet include cormorants, gannets, pelicans, kingfishers, gulls, terns, and some species of herons, egrets, and bitterns. While they may occasionally eat other prey, fish make up the bulk of their diet.
Major Groups of Fish-Eating Birds
Some of the major groups of birds with species specialized for eating fish include:
Pelicans
Pelicans are large waterbirds with long bills and huge throat pouches used for catching fish. The eight living pelican species are found on lakes, coasts, and rivers around the world. They feed by plunging their heads into the water to scoop up fish.
Cormorants
Cormorants are medium-sized waterbirds with long necks and slender, hooked bills for catching fish. There are about 40 species of cormorants worldwide. They often perch on rocks or branches and dive into the water to pursue prey.
Gannets
Gannets are large seabirds that specialize in plunge diving for fish. There are six species found across the oceans. They have long, pointed wings and dagger-like bills. Northern gannets can dive from heights of over 30 meters to catch prey.
Kingfishers
Kingfishers are brightly colored, medium-sized birds with large heads and long, dagger-like bills adapted for catching fish. There are over 90 kingfisher species worldwide found near waterways and coasts. They catch fish by plunging from perches.
Herons
While herons eat a variety of aquatic animals, some species specialize in fish as their main prey. These include tiger herons, green herons, and some species of night herons and egrets. Long legs, necks, and harpoon-like bills help them catch fish.
Gulls and Terns
Many gulls and terns are also specialized fish eaters. They use their excellent eyesight and maneuverability to dive for schooling fish or steal prey from other birds. Skimmers have uniquely shaped bills to help them scoop up small fish.
Unique Adaptations for Eating Fish
Fish-eating birds have evolved a number of anatomical and behavioral adaptations to help them catch and consume their slippery, aquatic prey:
- Streamlined bodies built for diving and swimming
- Oil glands to help repel water and keep plumage waterproof
- Long, sharp bills to spear, grip, and carry fish
- Long wingspans for soaring over water
- Excellent eyesight to spot prey below the water’s surface
- Ability to plunge-dive from heights to pursue prey underwater
- Tactics like coordinated group hunting
These adaptations allow fish-eating birds to thrive around waterways where fish are abundant. Excellent fishing abilities give them reliable access to a nutritious, high-protein food source.
Types of Fish Eaten
Fish-eating birds prey on a diversity of fish species. The types of fish depended on the habitat and diving abilities of different birds. Some major types of fish consumed include:
Surface Schooling Fish
Birds like gulls and terns commonly feed on small, schooling forage fish found near the water’s surface, including menhaden, anchovies, herring, and sardines. Their agile flight helps them dive into schools.
Large Pelagic Fish
Powerful divers like gannets and boobies regularly take large open ocean fish like mackerel, tuna, and flying fish. Cormorants also take bigger fish like salmon once waters warm.
Bottom-Dwelling Fish
Penguins and cormorants that dive deeply pursue fish dwelling near lake and ocean bottoms, including cod, sculpins, and flatfish. Herons spearing in shallows take catfish, perch, and sunfish.
Bait Fish
Kingfishers, tiger herons, and other shoreline-hunting birds grab small fish in shallows, including minnows, killifish, sticklebacks, and fingerlings. Quick reflexes help them snatch elusive prey.
| Bird Group | Examples of Fish Eaten |
|---|---|
| Pelicans | Menhaden, mullet, perch, sunfish |
| Cormorants | Cods, salmon, rockfish, sculpins |
| Gannets | Mackerel, tuna, flying fish |
| Kingfishers | Minnows, killifish, sticklebacks |
| Herons | Catfish, perch, sunfish, baitfish |
| Gulls/Terns | Anchovies, herring, menhaden, sardines |
Hunting and Feeding Strategies
Fish-eating birds use a variety of hunting strategies tailored to their anatomy and prey:
Plunge-Diving
Gannets, pelicans, boobies, and terns plunge directly down from flight into the water to pursue fish. This ambush tactic helps them take prey by surprise.
Diving from Perches
Cormorants, kingfishers, and some herons dive from perches like overhanging branches, rocks, or posts. This gives them an aerial view to spot prey.
Wading
Herons and egrets wade through shallows watching for fish passing by. Their lightning-fast reflexes allow them to stab prey.
Surface Seizing
Skimmers cruise with their specialized open bills at the water’s surface, snapping up small fish. Gulls also pick small fish from the surface while swimming or flying.
Coordinated Hunting
Some pelicans, cormorants, and herons hunt in groups, flushing fish into tight areas where they’re easier to catch.
Once caught, most fish are immediately swallowed whole. Pelicans and cormorants have stretchy throat pouches to contain large, slippery fish and drain water before swallowing.
Examples of Fish-Eating Bird Species
Brown Pelican
- Dives from 20-65 ft to take fish in coastal areas
- Large throat pouch can hold 2-3 gallons of fish and water
- Feeds on menhaden, mullet, sheepshead, and perch
Double-Crested Cormorant
- Plunge dives from the surface down to 45 ft depth
- Hooked bill helps grasp slimy, wriggling fish
- Eats bass, perch, suckers, trout, and other freshwater fish
Belted Kingfisher
- Perches over water then dives for small fish
- Spears prey with long, dagger-like bill
- Feeds on minnows, sticklebacks, and young game fish
Great Egret
- Slowly stalks shallow water waiting to ambush fish
- Uses precision bill strikes and foot stirring to herd prey
- Eats sunfish, catfish, shad, and smaller saltwater fish
Ring-Billed Gull
- Dips down to snatch small fish from surface while flying
- Scavenges dead fish and steals from other birds
- Eats alewives, shad, menhaden, mullet, and minnows
Threats and Conservation
Though well adapted for fishing, these birds still face a number of threats:
- Habitat degradation – Pollution, development, dams etc. can reduce food supplies and nesting areas.
- Overfishing – Depletion of fish stocks by humans leaves less prey available.
- Disturbance – Many species rely on undisturbed nesting colonies.
- Invasive species – Nests are vulnerable to takeover by invasive species.
- Oil spills – Oil spills pose a major hazard, especially to plunge diving seabirds.
Protecting wetlands, managing fisheries sustainably, preventing oil spills, and reducing disturbances are key conservation goals to preserve fish-eating birds.
Many fish-eating species were decimated in past centuries by overhunting for feathers and eggs, though have rebounded under modern protections. Maintaining healthy populations of these unique fishing birds remains an important focus.
Conclusion
Birds that rely primarily on fish and other aquatic life for food represent a diverse array of species worldwide. Pelicans, cormorants, gannets, kingfishers, some herons and egrets, gulls, terns, and other groups have evolved specialized adaptations that make them powerful fish hunters. Long bills, stretchy throat pouches, oily waterproofing, and plunge-diving abilities allow them to pursue fish in lakes, rivers, and oceans. Though faced with some conservation threats, these iconic and often majestic piscivorous birds remain vital components of aquatic ecosystems. Protecting wetlands and fisheries is key to preserving healthy fish-eating bird populations into the future.
