a shark below the water
A silky shark in the Jardines De La Reina, Cuba.Photo Credit: © Lorenzo Ragazzi/TNC

I heard the story countless times in my youth: a female duck and her ducklings swam along a lake’s edge, pecking at grasses and insects. One duckling strayed a bit far from mother, and suddenly the water erupted in an explosive splash. The duckling vanished, the dinner of a startlingly large fish.

Most of the people who told such stories were what you might charitably call unreliable narrators. The stories were also almost never firsthand accounts, but something witnessed by a cousin’s best friend’s barber. The stories were fishing tales, not science.

But thanks to YouTube, David Attenborough and actual research, we now know that sometimes fish doeat birds.

It’s not often. There is a lighthearted Twitter debate among biology nerds called #BirdVsFish. In truth, birds have the upper hand (errrrr..wing?) most of the time. A lot of birds specialize in feeding on fish.

But when fish do feed on birds? It’s dramatic, and perhaps even a bit disturbing. Here are some examples.

  • Targets of Opportunity

    First: yes, northern pike, largemouth bass and other large, predatory fish really do eat the occasional duckling. A quick search of YouTube will provide you with ample evidence of this, although I suggest you not undertake this task unless you have several hours to spare.

    You will read some claims, often on fishing blogs, that ducks actually form a significant percentage of a pike’s diet. There is little evidence to support this notion. As early as the 1950s, some wildlife managers feared pike were eating too many ducks on national wildlife refuges. But when those managers conducted studies, they struggled to find any duckling in pike stomachs.

    Many predator fish species are opportunists. A fish like a northern pike preys primarily on other fish and crayfish. But it won’t pass up free protein. If a critter is small enough to fit in its mouth, the pike will likely eat it. This is why you catch big fish on goofy-looking lures.

    A pike will eat a garter snake or a mouse or a blackbird or a duck. It is not selective.

    This doesn’t mean pike actively hunt ducklings. In most instances, there will be far more minnows around than ducks (and the small fish are easier to catch). However, there are instances when fish could key in on birds as prey. Anytime you have a concentration of wildlife, predators will take advantage of the bounty. A colony of nesting birds along the water’s edge, for instance, could draw fish that pick off any baby birds that fall.

  • The Eagle Has Landed (In a Fish’s Stomach)

    Bald eagles regularly dine on fish, but there is one documented instance in which the tables turned. The U.S. Fish and Wildlife Service reports on one instance where two pike sampled in a river contained partially-digested bald eagle chicks.

    Obviously, bald eagle chicks are not usual prey for pike. Apparently both birds fell out of the nest, and two different fish took advantage.

    The U.S. Fish and Wildlife Service report includes these details:

    But two northern pike captured on 11 June 2000 had recently consumed newly hatched chicks of the bald eagle (Haliaeetus leucocephalus), a species that to our knowledge has not been reported previously as prey of northern pike. Both bald eagle chicks were positioned head forward, and their posterior regions were partially digested. We estimated the chicks’ ages from their development as younger than five days. The northern pike predators were 71 and 77 cm fork length.

  • Of Catfish and Pigeons

    In one section of the River Tarn in southwestern France, a large catfish species not only actively seeks pigeons, but does so by attacking the birds on land.

    The wels catfish is a predatory and adaptable species frequently featured on shows like River Monsters. It has been introduced well beyond its original range in Europe. It adapts readily to the local prey, but the River Tarn presents a wild twist.

    Pigeons drink water from a river island, and the catfish hunt along the edges. The catfish lunges onto the gravelly water’s edge, beaching itself. It then grabs a pigeon and pulls it back into the water. Millions of viewers became familiar with this spectacle through the documentary Planet Earth II.

    The catfish exhibit hunting behavior quite similar to orcas in Chile that beach themselves to kill seals.

    These catfish can reach immense sizes. But science writer Ed Yong notes that it is generally the smaller catfish that hunt pigeons. Yong hypothesizes that the smaller catfish may find it easier to get back in the water after beaching themselves.

    As an angler, I’d love to target these pigeon-eating catfish. I’d want to cast a suitably-weird lure (perhaps the Savage Duck) right along the water’s edge, twitch it and wait for the ensuing explosion. It would have to one of the ultimate urban angling adventures.

  • More River Monsters

    Two other freshwater fish are commonly listed as bird predators. The Mongolian taimen is the largest member of the salmonid family, and has a deserved reputation as a fierce predator. Ducks and other birds are often listed as part of its diet.

    I could find no concrete evidence that shows taimen eating ducks. However, taimen have been documented eating many rodent species. A Japanese taimen was found with more than 40 lemmings in its stomach. It would seem like a duckling would be a likely snack for such a fish.

    The Murray cod is the largest exclusively freshwater species in Australia; it is also reported to eat water birds. In this case, there is a lot of documentation to go with the claims.

    At the Narrandera Fisheries Centre, Murray cod are bred to be restock fisheries where their populations have been depleted. When the fisheries managers caught one of the breeding cod in this center, it would regurgitate black ducks.

  • Shark Attack

    Unsurprisingly, several shark species nosh on sea birds if the opportunity presents itself. However, around the Hawaiian islands, a small population of tiger sharks has learned to return each year to feed on young albatrosses.

    Albatrosses are superb long-distance flyers, with the longest wingspan of any bird. But the young make frequently crash landings in the water, and it’s difficult for them to get airborne again. The tiger sharks feast on this easy prey.

    According to the Inquistr: “Only a small population of tiger sharks have discerned that the albatross breading season will lead to easy prey for them, yet the group that returns to the Hawaiian Islands each year in anticipation of this event can consume a full 10 percent of all chicks reared in a season. Peak hunting time only lasts a few weeks, before the birds are strong enough to leave the island, giving the tiger sharks little reason to remain in the area.”

  • The Sooty Tern Hatch

    The giant trevally is known in fly fishing circles as one of the most ferocious, hard-fighting fish. There are frequent stories of a giant trevally eating a fly, only to have others try to rip the fly out of the hooked fish’s mouth.

    On one atoll in the Seychelles, sooty terns nest on the edge of an island. The giant trevally have learned to hunt these birds when they fall in the water, a spectacle that has achieved fame through the documentary Blue Planet.

    According to Peter McLeod in his book, GT: A Fly Fisher’s Guide to Giant Trevally,

    “Big fish have been witnessed coming in on the waves from the ocean, hanging around until they target a fledgling or even a fuly-grown specimen, tracking it and then taking it from the air in one hit before returning to the ocean to digest the meal.”

    McLeod mentions one intrepid angler who fished this “hatch” by using a “tern fly” made from a black flip-flop. Sign me up.