A single female common merganser leading a long, tight line of more than 50 ducklings (56 in the count most widely shared online) across Lake Bemidji in northern Minnesota: that is the scene amateur wildlife photographer Brent Cizek caught from a small boat in late June 2018. The photo spread around the world and was later featured by the National Audubon Society. People wanted to know one thing above all: could one duck really have that many babies?
The short answer is no, not by herself. A merganser lays roughly a dozen eggs at most in a normal clutch. What Cizek photographed was almost certainly a creche, a mixed group of young from several broods that ends up following one adult female. It is a known and fairly common behaviour in mergansers, and the photo is a rare, clear record of how big such a group can get.
How the photo was taken
Cizek was out on Lake Bemidji with one camera and one lens on a windy day, by his own account not ideal conditions for a small boat. Near the shoreline he spotted what looked like a cluster of birds. As he moved closer, the shape resolved into a duck followed by a long tail of ducklings, and he later described his heart racing because he had never seen anything like it.
The birds began swimming out into open water. With waves tossing the boat and the group hard to keep in frame, he fired off around 50 frames and hoped that at least one would be sharp. Back home, he found that just one was in focus. Counting the ducklings in it, he found more than 50; the figure of 56 is the one that circulated with the photo.
He posted the image online and it was quickly shared widely, picked up by news sites and by Audubon. Cizek, a keen supporter of bird conservation, said he hoped the picture would encourage people to care about birds and the places they live. He also said the female looked proud and calm at the head of the line, and that he wondered how she managed to look after so many young.
Meet the common merganser
The common merganser (Mergus merganser), called the goosander in Britain and Europe, is a large diving duck of lakes and rivers across the northern hemisphere. Unlike dabbling ducks such as mallards, mergansers are fish-eaters. Their slim, serrated bills, sometimes called sawbills, are built to grip slippery prey.
Females have a grey body and a rusty-brown head with a shaggy crest; males in breeding plumage are mostly white with a dark green head. In North America they breed across Canada and the northern United States, including the lakes of northern Minnesota.
Mergansers usually nest in tree cavities, old woodpecker holes or nest boxes near water. Within a day or two of hatching, the ducklings leap from the nest, sometimes from a considerable height, and follow their mother to the water. They feed themselves from the start, diving for insects and later small fish, while the adult guards and guides them.
Why one duck can lead so many ducklings
Two separate behaviours can produce a group like this, and they are often confused.
Egg-dumping (brood parasitism)
Female ducks of several species sometimes lay eggs in other females' nests, a habit biologists call intraspecific brood parasitism, or more informally egg-dumping. Cavity-nesting ducks such as mergansers, goldeneyes and wood ducks are well known for it, partly because good nesting holes are scarce. A nest can end up holding far more eggs than one female laid. Even so, a nest producing 56 ducklings is very unlikely.
Creches (brood amalgamation)
The more important explanation is what happens after hatching. Merganser broods often merge on the water. Ducklings that lose track of their mother, or whose mothers leave early, may join another family, and some females tend to collect young from several broods. The result is a creche: one or a few adults escorting dozens of ducklings. In mergansers these groups can be very large, and observers have recorded creches of dozens of young.
So the female in Cizek's photo was probably not the biological mother of most of the ducklings behind her. That takes nothing away from the image. She was still the one leading and guarding them.
Why ducklings benefit from a big group
Safety in numbers is part of it. Young ducklings face predators from every direction: pike and large fish from below, gulls, eagles and herons from above, and mink or otters along the shore. In a large group, the chance that any one duckling is taken drops, and more eyes can spot danger. Following an experienced adult also helps young birds find good feeding areas.
For the adult, the extra cost of a few more ducklings may be small, because the young feed themselves. That helps explain why a female will tolerate or even attract strangers. Researchers still debate exactly how much each side gains, and the answer probably varies with predators, food and the number of adults around.
The group kept growing
Cizek went back to the lake to see the family again. A few weeks later he saw the same female with about two dozen more young, 76 ducklings in all, which suggests she had picked up even more strays along the way. That later count belongs to a different day and a different set of photos, so it is best read as a sign that the creche was still absorbing young rather than as a correction of the original photo.
The video below shows the line of ducklings on the water and gives a sense of how the group moved.
If you see a duck family like this
Large duck creches are a delight to watch, but they are vulnerable. Give them space, especially from a boat: keep well back, cut your speed and avoid splitting the line, because ducklings separated from the group are at real risk. Keep dogs leashed near shorelines in late spring and early summer, and do not feed bread to ducks or ducklings; it offers little nutrition and can foul the water.
If you find a single duckling alone, it is usually best to watch from a distance for a while, since the adult may be nearby. If it is clearly orphaned or injured, contact a licensed wildlife rehabilitator rather than trying to raise it yourself.
Sources: Audubon: Here's why this mama merganser has more than 50 ducklings; Live Science: This duck supermom leads 76 ducklings; Wikipedia: Common merganser; Wikipedia: Brood parasite; Healthy Food House: Super mom spotted on a Minnesota lake with 56 ducklings in tow. Photograph: Brent Cizek, as featured by the National Audubon Society.
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