For many people vacationing in the lake-filled woods of Northern Wisconsin, the haunting cry of the loon is the sound of summer. About 4,000 of the black-and white birds nest in the state by May or June and it’s not uncommon to find fluffy gray loon chicks riding around on their parents’ backs. But researchers counting loon chicks recently found something unusual during their rounds: Instead of a gray chick they found a fluffy yellow mallard chick perched on the back of a loon. And even stranger, the loons have continued to raise it as their own throughout the summer.
According to the Loon Project, a scientific study that has been studying northern Wisconsin’s loons since 1993, Evelyn Doolittle, a college student counting and monitoring the loon chicks, came back from a visit to Long Lake in Oneida County in the north central part of the state where she’d seen her first chick. She commented that baby loons and baby ducks sure looked similar. Veteran loon counter Elaina Lomery didn’t think too much about the observation. Both chicks are small, fluffy and hang out with their parents. But when she visited the nesting pair at Long Lake herself ten days later, she found to her surprise that indeed the chick was a duckling, riding around on one of the loon’s backs.
Ryan F. Mandelbaum, writing for Audubon, reports that a month later, the interspecies family was still together, with the loons still feeding the growing duck, letting it hitch a ride and teaching it to dive. Mallards are “dabbling” ducks, meaning adults feed by dipping their heads underwater with their tailfeathers to the sky eating vegetation and invertebrates. While they can dive under the water if necessary, it’s very rare behavior. Loons, on the other hand, are divers and can stay underwater for extended periods, chasing fish. The baby mallard has been observed taking small fish from its adoptive mama, but it turns away the large fish its proud papa tries to feed it.
The pairing is especially unusual since loons and mallards aren’t on friendly terms. “Loons invariably try and drive off mallards when they see them on the water; they’re kind of enemies,” Walter Piper, director of the Loon Project tells Mandelbaum. “It’s exciting and bizarre to have a Mallard raised by loons.”
So how did the little duck end up in a loon family? Researchers did find a loon nest on the shores of Long Lake with the remnants of one shell, indicating the couple hatched a loon chick that likely did not survive. Around the same time, the duckling likely became separated from its family. Loons, Piper says, are known for adopting loon chicks separated from their families.
“Loon pairs provide extensive parental care for their young, of course, and are hormonally primed to do so,” he writes on the Loon Project blog. “In any event, the tiny waif was likely discovered by the loon pair just after they had lost their chick and were predisposed to find and care for anything that even remotely resembled a newly hatched loon.”
Cultural differences have caused a few hiccups along the way. Chelsey Lewis at the Milwaukee Journal Sentinel reports that loon chicks are pretty casual about being fed and just wait for their parents to bring them their fishy snacks on their own time. The duckling, however, rushes up to mama as soon as she surfaces with food, begging for bite. It’s an especially unusual behavior because mallard mothers do not feed their ducklings directly.
The mallard also lacks some instincts baby loons might have. In July and August, single loons patrol the skies looking for their own breeding territories and mates. One sign of a good lake is the presence of a breeding pair with a chick. If a single loon sees this, they may challenge one of the parents to single combat and evict them from the lake, taking over their family. That’s why, when another loon flies overhead, the chick dives or hides on shore while the parents head for the center of the lake and pretend that they’re a childless couple.
The duck, however, doesn’t know this drill and didn’t follow procedures when another loon did appear. “Instead of diving itself and racing underwater to hide near shore, as a loon chick would have, the duckling freaked,” Piper writes. “When it spotted its foster parents far away and next to non-breeders that had landed, the duckling raced towards middle of the lake, while peeping loudly, making itself very obvious.”
Luckily, the interlopers were confused by the whole situation, and everything turned out swimmingly.
So, what will happen to the duckling, once it’s fully grown, which should happen by the end of the summer? Lori Naumann, a spokesperson for the Nongame Wildlife Program of the Minnesota Department of Natural Resources, tells Mandelbaum that the mallard will probably find its way back to its own flock.
“It will still probably figure out that it’s a duck,” she says. “It’s going to seek different habitat, and eventually, its food source will change to plant matter.”
Piper also says it’s likely the diving duckling will find its own kind, though that’s not for. certain. Whatever the case, these few months have been special. “In short, we know bits and pieces of the story of how a pair of loons came to care for a mallard duckling. Much regarding this series of unlikely events remains shrouded in mystery,” he writes. “Even in our considerable ignorance, though, it is impossible not to marvel at this charming spectacle.”
Interspecies families in the bird world are rare, and the mallard/common loon combo has not been seen before. Lewis reports that researchers documented Arctic loons taking care of an eider duck in the 1970s. Loons in British Columbia were also documented taking care of a goldeneye duckling a few years ago. In 2017, scientists watched as bald eagles in British Columbia raised a red-tailed hawk chick as their own. The same phenomenon is happening this summer in Redding, California.
The saga of the loony mallard is something of a bright spot for this year’s loon families. The Loon Project found that chicks only hatched on about one quarter of the 120 lakes they are monitoring, down from about half last year. That was likely caused by ice that stayed very late into the breeding season on the lakes and the loon population in the state appears relatively stable for now. However, models created by Audubon estimate that climate change will push breeding loons, and whatever types of chicks they're caring for, out of the state completely by 2080.