Cormorant Fishing Behavior: How They Hunt and Catch Fish

What is cormorant fishing behavior?

Cormorant fishing behavior is the set of actions these birds use to locate, pursue, and capture fish. On prairie lakes, you'll most often see double-crested cormorants hunting alone or in loose groups. Their method involves diving from the surface, chasing fish underwater with powerful webbed feet, and surfacing to swallow the catch. Unlike ospreys or eagles, cormorants do not plunge from the air; they slip under from a floating position. This behavior is efficient and highly adapted to the open, often shallow waters of the prairies.

How do cormorants dive and pursue fish underwater?

Cormorants dive from the surface with a small forward leap or a quiet sinking motion. They compress their feathers, reducing buoyancy, and use their feet for propulsion. Their wings are held tight against the body; only the feet drive them forward. A dive may last 30 to 70 seconds, though most are under 30 seconds. Cormorants can reach depths of 5 to 25 meters, but in prairie lakes, which are often less than 10 meters deep, they work near the bottom or in open midwater. Underwater pursuit is direct: they chase fish, not ambush them. Watch for a bird disappearing with a slight splash, then resurfacing often far from where it went down.

What conditions affect diving?

Water clarity influences hunting success. Cormorants rely on vision, so clear water helps them spot fish. On windy days, choppy water may make dives shorter or less frequent. Cold water does not stop them; their dense, wettable feathers actually help by reducing drag. You may notice cormorants spending long periods with wings spread after fishing—this is to dry their feathers in the sun and wind, not to cool off.

What fish prey do cormorants eat on prairie lakes?

Cormorants are generalist fish-eaters. On prairie lakes, common fish prey include yellow perch, walleye, northern pike, whitefish, and various minnows. They also take small carp, suckers, and sticklebacks. Prey size usually ranges from 5 to 25 cm. Cormorants do not store fish; they swallow each one head first, usually right after surfacing. Because they eat a variety of species, their impact on any single fish population varies by lake and season. During spring and fall migrations, their numbers and feeding pressure can be higher on larger lakes.

How do cormorants handle prey after catching it?

Prey handling is quick and practical. A cormorant usually surfaces with the fish crosswise in its bill. It then flips the fish to orient it head first, using small tosses or underwater shakes. Swallowing is immediate. If the fish is large or spiny, the bird may spend several seconds adjusting the angle. Sometimes a cormorant will bring a fish to a perch—a rock or dead tree—to reposition it. Gulls or other birds may try to steal fish during this vulnerable moment, so watch for brief chases.

Do cormorants hunt in groups?

Yes, group foraging is common, especially when fish are schooling. You may see a line or semicircle of cormorants moving together, diving and surfacing in loose coordination. This behavior can concentrate fish, making them easier to catch. It is not a true cooperative hunt like pelicans; each cormorant catches its own fish. Group foraging often happens in late summer when young fish are abundant. Single cormorants also feed independently, particularly in small ponds or when prey is scattered.

What can birdwatchers notice and how can they prepare?

On your next outing to a prairie lake, look for these signs of cormorant fishing behavior: a bird floating low in the water, a sudden smooth dive, a long pause, then a resurfacing with a fish. Bring binoculars to see prey handling details. A notebook helps track dive times and fish sizes. Season matters: spring and fall migrations bring more birds; summer offers nesting colonies and regular feeding flights. Respect nesting islands and roost sites—keep a distance of at least 100 meters if possible. Cormorants are protected under the Migratory Bird Treaty Act in the U.S., so disturbing them or their nests is illegal. Quiet observation from a shoreline or boat yields the best views.

Comparison of cormorant fishing tactics across conditions

Remember that these are general patterns; cormorant behavior varies by lake and individual. Patient observation will reveal the local rhythms.