Fish are essential to many birds’ diets, from small kingfishers to massive eagles and pelicans. But how are they able to catch these fish with such ease? Birds use different strategies to enter the water and eat a good meal.
Birds catch fish in three main ways. Some birds will dive into the water to catch fish, birds that grab fish from the surface, and birds that sit on the water surface and dive. A bird’s body shape, bill, feet, and eyesight all help birds catch fish.
The different ways that birds catch fish are fascinating. This article examines how they do this and how their bodies help them.
Birds That Dive
Many fish-eating birds will come in from above, flying over the water and waiting for the perfect time to strike or waiting on perches. They will enter the water at just the right angle, snatch their prey and return to the air to repeat the process. One of the most impressive birds to do this is the northern gannet. Gannets are large sea birds that can dive with great power into the water. They often come together around large shoals and can be seen fishing alongside marine mammals.
Kingfishers are different and wait patiently on perches darting in and out of the water with ease. These birds do their best to be at the right height, but this comes more naturally to long-legged waders like herons and egrets. Heron species can stand statuesque by the water, waiting for the right moment to strike. Egrets, meanwhile, are more active.
Some birds from above try their best not to enter the water. Ospreys and eagles will swoop in with their feet outstretched, grab the fish, and use their powerful muscles to lift it back into the air and away to somewhere they can feed. Black skimmers will fly close to the water with their bills open and scoop up what they can, using as little energy as possible.
Surface divers will spend their time on the surface of a lake or the ocean, periodically diving down to hunt for prey. The loon can dive for as long as five minutes, using their heavier bodies to descend deeper into the water and search for food. You could see one dive, which could be a while before it reappears at a different point on the lake.
Species like cormorants will also take big chances on larger fish that smaller birds can’t carry. Birdwatchers are often amazed to see them struggling with large fish like adult salmon and somehow managing to swallow them whole.
Birds that fish need the perfect tools for the job, which can vary depending on how they hunt. The physical adaptations of fishing birds are also important for successful hunting. The body shape is essential, as are the differences in attributes like their bills and feet. Those that enter the water need to do so safely and effectively. It also helps to have good eyesight to handle the properties of the water.
Body shape can also make a big difference. When chasing after them in the water, birds need a streamlined body to enter the water and come away with their prize. Many sea birds will have a longer neck, sleek bodies, and legs positioned further back. This can make them awkward in the air or on land but brilliant underwater.
The gannet takes this idea of the perfectly streamlined body to new levels. It can tuck in its pointed wings as it descends into the water like a missile. They can do this from 100ft in the air and range speeds of 60mph, propelling them deeper into the water than other birds. Therefore, they can reach more fish than those just at the surface. This is a dangerous activity, and the birds must hit the water at just the right angle to avoid breaking their necks. They also have air sacs in their face and chest that act like airbags.
A lot of these birds have very different bills depending on their methods. The skimmers are out of proportion and perfect for fishing on the top of the ocean. Pelicans take this further with their big pouches to scoop up fish. However, the small Atlantic puffin can also handle many fish at once. It lines them up neatly with barbs on its tongue, taking as many back to the nest as possible.
When it comes to the feet, it helps if those surface divers are broad and webbed to handle the water better. Egrets, meanwhile, have bright yellow feet that move around in the water. There is debate over whether this is to disturb prey in the silt, act as an enticing lure, or both. Fish-eating hawks and eagles can rely on their powerful talons, with the osprey holding the fish straight ahead to remain aerodynamic.
The bird’s eyesight also plays a significant role in their chance of success. Birds that dive underwater need to be able to see what they are doing. They have a third nictitating eyelid that comes over and protects the eye while also allowing for as much visibility as possible. Many birds that hunt from above can also judge distance perfectly and correct for the refraction of the water to locate their prey.
Hunting for fish is easy if you have the skills and the physical adaptations to succeed. Many birds here have evolved to become proficient at catching fish and provide a service for controlling population numbers. But, other species realize they can get a good meal by stealing fish rather than hunting for them.
Gull species will take what they can get that washes up on a shore. Eagles will even see if they can harass other birds – either younger eagles or osprey – into giving up their catch. The worst culprit in all of this is the parasitic jaeger. This is a kleptoparasite, meaning it will spend its time stealing the hard-earned catches of other birds. It is an easy way to save energy and get a good meal.
Bryan Harding is a member of the American Society of Mammalogists and a member of the American Birding Association. Bryan is especially fond of mammals and has studied and worked with them around the world. Bryan serves as owner, writer, and publisher of North American Nature.