Long Lake in Washburn County, Wis. is seeing a new twist on the classic ugly duckling tale. Rather than a flock of ducks adopting a baby swan, researchers have witnessed a pair of wild loons adopt an orphaned mallard duckling.
The unlikely grouping was first spotted on a rainy day this past June by a member of the Loon Project’s research team, a scientific group that observes the behaviour of common loons. The researcher who first made the observation was new to the team and with her vision obscured by poor weather, she assumed it was a loon chick. But on the Loon Project’s next visit, one of the team’s veteran researchers spotted the little fuzzball hopping a lift on a loon’s back and immediately identified it as a mallard duckling.
The grouping comes as quite a surprise considering loons have been known to attack and kill adult and duckling mallards. “There’s no love lost between mallards and loons,” says Walter Piper, a biology professor at Chapman University and the founder of the Loon Project.
Piper hypothesizes that this “improbable family” was brought together after the loons lost their own chick. Crossing paths with the wayward duckling likely engaged their parental instinct. “Animals are hormonally primed by the hormone prolactin to show parental care,” Piper says.
This includes loons, meaning they have a strong behavioural tendency and physiological basis to be protective of their young, feed their young, stay near their young, and chase predators away from their young. Impulses that would have still been present after losing their own chick.
“When you think of a loon pair that’s just hatched their eggs that have small chicks, they’re going to be in the position where they strongly want to take care of something, and so it’s not all together surprising and without precedence that they should have adopted a mallard duckling that was also looking for some parental care from the other perspective.”
While the relationship does seem novel, it isn’t the first time loons have adopted ducklings. There have been reports of common loons rearing goldeneye ducklings in British Columbia, and a study from the ’70s that claimed arctic loons had adopted five eider ducklings.
What makes this case so remarkable is the duckling’s ability to adopt and mimic the loons’ behaviours. “Mallard ducks are dabblers,” Piper says. Meaning they grab food along the shoreline and upend themselves in shallow water. But “this is a duckling that dives, or at least dove a number of times and got to the bottom of the lake and retrieved a snail on one occasion… just like its foster parents do and unlike its own species would.”
The duckling has also developed a taste for fish, a delicacy not often found on a mallard’s menu. The loons would feed the fish to the duckling directly; an uncommon trait considering mallards do not feed their young. Instead, they bring them to feeding areas, prompting them to forage for themselves.
The duckling stayed with the loon pair for 70 days, approximately 10 days longer than it would have with mallard parents. “We presume it fledged just as a mallard would, except it spent a little bit of a longer time with its parents than it would have ordinarily.”
Despite having grown to adult size, the duckling hasn’t betrayed its loon upbringing. “You’ll see that [loon chicks] stand on the parent’s back at varying sizes,” Piper says. “[The duckling] did it when it was just about full size, and it was so heavy that it would almost sink its parents totally in the water.”