Fish are an important part of many birds’ diets, from small kingfishers to massive eagles and pelicans. But, how are they able to catch these fish with such ease? Various bird species use many different strategies to enter the water and come away with 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. In this article, we look at how they do this and how their bodies help them.
Birds That Dive
Many fish-eating birds will come in from above, either 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 to do this from the air 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 just 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 that come in from above try their best not to enter the water at all. 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 in the process 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 has the ability to dive for as long as five minutes at a time, using their heavier bodies to descend deeper into the water and search for food. You could see one dive and it 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. It doesn’t matter if they can’t take off for a little while under the weight as a surface diver.
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 important, as are the differences in attributes like their bills and feet. Those that enter the water need to be able 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, which propels 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 need to 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 is also able to handle many fish at once. It lines them up neatly with barbs on its tongue, taking as many as possible back to the nest.
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 big 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 great if you have the skills and the physical adaptations to succeed. Many birds here have evolved to become proficient at taking all kinds of fish and providing a great service for controlling population numbers. But, other species realize that 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, which means that 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.