BLANE KLEMEK OUTDOORS: Trumpeter swans of Assawa Lake

Trumpeter swans
A pair of trumpeter swans swim on the open water of the Mississippi River between Lake Irving and Lake Bemidji on March 21. (Annalise Braught / Bemidji Pioneer)

The trumpeter swan couple of Assawa Lake became proud parents of five precocious cygnets on June 10. And so far all seven birds, mom and dad included, are doing well.

While I have no way of knowing for certain, the chances are good that Assawa’s resident swan-pair are the same birds that laid claim to the lake for the last two or more years, but as non-breeding adults it typically takes two to four years before a bonded pair nests for the first time. Arriving well before the ice disappeared on April 22, it didn’t take long for the love birds to commence nest-building activities following ice-out.

I’ve never had a front row seat to trumpeter swan nesting behavior, and what a delight it was from start to finish. The pair chose a location directly across the basin from the furthest extent of my modest backyard. The distance from the lawn to the other side of the lake where the swans built their large nest-mound was about 200 yards, or the length of two football fields.

How exactly swans, or any bird for that matter, communicate and coordinate the innate behavior of nest-building is a fascinating subject all by itself. There’s definitely plenty of communication and pair-bonding that occurs between mated pairs of birds that share nest construction duties, swans included. Searching for nest sites and nest building are integral parts of courtship.

As the trumpeter swans of Assawa Lake began building their large nest on a mat of floating vegetation where the sedge meadow meets the open water, I understood why they chose such a location, especially when the vegetative nest began growing in height. Coupled with the nest’s three-foot height and each of the incubating birds’ five-foot long outstretched necks, the swans would have a commanding 360-degree view for spotting predators and trespassers.


My enjoyment of observing the swans building their nest was enhanced by a pair of binoculars. Each bird carried bits of vegetation, usually last season’s dried-up cattail stalks and leaves. Once the nest was finished, these cattail bits and pieces took on the appearance of a corn shock or muskrat lodge. And when the female swan began testing out her nest-bowl with her body by sitting in it, she began using her neck like a long-reach excavator as she dredged up other vegetation with her beak to fortify and shape her nest just so.

The female swan (females are called pens) began laying an egg a day during the last days of April/first part of May. Soon after, her vigil began of near non-stop incubation of her very large, five-inch long eggs. Her mate (males are called cobs) also shared in incubation duties so the female could feed and stretch her legs. Sometimes, especially early in the incubation process when the weather was mild, the nest would be abandoned for short periods of time while both swans swam and foraged together.

By the time the morning of June 10 arrived, I had been making multiple daily trips to my vantage point to hopefully observe the moment the cygnets hatched, as I knew the time was close, since incubation began a month prior. It generally takes four to five weeks for hatching to occur. As I stood peering through the optics, I began to make out small grayish-colored puffballs protruding from underneath the resting swan in her nest.

After hatching, cygnets and other waterfowl nestlings like ducklings and goslings often stay inside the nest for up to 24 hours as their mother broods them to keep them safe and warm. Holding true to this behavior, the next morning I was thrilled to see both parents slowly swimming about the lake with five newborn cygnets in tow. The parents, often busily foraging in their graceful underwater head-and-neck submersions, were dislodging pieces of plant material and protein-rich insects as the hungry cygnets feverishly fed on whatever floated up to the surface.

And each evening after sunset during the cygnets’ first week of life on Assawa Lake, the doting parents led their brood back to the nest. The female would then climb up into it, followed by each cygnet one-by-one in order to spend the night safe and warm with mom. Meanwhile, dad, understandably wore out from a long day caring for the kids, would sleep onshore a few yards away with his neck and head limply slung over his back.

A day in the life of a trumpeter swan family is only one of the limitless natural marvels occurring right now during Minnesota’s glorious springtime. Indeed, that we all have front row seats to Mother Nature’s wonders are blessings to be thankful for as we get out and enjoy the great outdoors.

Blane Klemek is a Minnesota DNR wildlife manager. He can be reached at


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