Meet the ducks that nest in trees

When most people think of ducks, they probably think of birds that quack and live on water. Well, most ducks don’t quack and some nest in trees! Let’s take a close look at two of our local tree ducks, both of which have nested at Stillman Nature Center in Barrington — the wood duck and hooded merganser.

Wood duck

The wood duck is one of the most beautiful species of waterfowl to be found on the planet. The male, in particular, is a spectacular bird. In the spring, he has an iridescent green and purple crested head, red eyes, white throat, and burgundy breast. The female, who also sports a crested head, has a distinctive white patch around the eye.

When perched on a branch or floating high on the water, the drake’s resplendent colors are quite visible. I say floating high since wood ducks are more buoyant than other ducks.

Paddling tall suits this duck fine since most of its diet is made up of seeds (including acorns) and aquatic plants. It does not need to dive for dinner.

Should you come upon a group of woodies that suddenly take flight, you will probably hear their wings whistling by. You might also detect a distinct squealing oo-eek, oo-eek call. These high-intensity vocalizations are made by the hens and used to keep in contact with the other ducks.

Filling cavities

Unlike some water birds, such as herons, that build stick nests in trees, wood ducks use cavities. Since they aren’t equipped to excavate their own holes, they use preexisting openings.

The majority of suitable nest cavities develop when large branches break, leading to the development of heart rot in the tree’s trunk. The trees should be at least a foot in diameter at breast height although nests are more common in larger trees.

Selecting the right cavity is done by the hen. The drake keeps her company, however. Unless she simply returns to last year’s nest, the search starts early in the morning and can last for hours.

Ideally, the cavity should be 30 feet or more above the ground although lower ones are often used. The entrance is usually between 10 and 19 square inches while the depth of the cavity averages just under two feet. These birds will also use nest boxes, which you can build — plans are available at many sites online.

Look out below

Ducklings are precocial, which means that their eyes are open and they are covered with downy feathers as soon as they hatch. By the end of their first day, the ducklings are ready to walk, paddle, and feed themselves. You could say that they hit the ground running which is exactly what they do!

The hen’s brood, numbering from nine to 14, usually leave in the morning, about 24 hours after hatching. Of course, they don’t jump until the hen has scanned the area for trouble. If the coast is clear, she flies down to the ground or water below and softly calls “kuk, kuk, kuk.”

This is the cue for the ducklings to leap from the cavity. Given the heights they fall from, the young are surprisingly resilient, literally bouncing off the ground. Once on terra firma, they can have quite a hike ahead of them. Some nest trees are up to a mile away from the nearest water.

Interesting thing, not every little bird in the duckling parade is the offspring of the duck that incubated it (more on this later).

Hooded merganser

Personally speaking, when it comes to the best looking Midwestern duck, the stylish black-and-white hooded merganser wins hands down.

As with the wood ducks, both males and females sport a crest on their heads. Unlike the wood ducks, the merganser drake knows how to work his.

His crest is bright white edged in black. Like a fan, it can be collapsed or fully expanded. As you might expect, it is put to full use during courtship.

Cruising the sand bars

The male merganser’s elaborate courtship behaviors include crest-raising, head-shaking, turn-the-back-of-the-head, upward-stretch, head-pumping, and, last but not least, ritualized drinking.

Should you want to watch merganser courtship displays at Stillman, visit the nature center soon. The hooded mergansers arrive almost as soon as the ice breaks up. If you visit later in the spring, you might see a family of mergansers or wood ducks.

Low riders

Merganser comes from the Latin meaning “diving goose.” The French know it as bec-de-scie or “saw-beak.” The Ojibwa word is ah-zig which translates as “obscure.” Now, let’s put these together.

The hooded merganser does dive for prey which includes small fish, frogs, crayfish, and aquatic insects. Its serrated bill provides a firm grasp on its slippery meals. But, obscure?

Yes. Unlike the wood duck, the hooded merganser often sits low, which it can do by compressing the air sacs in its body and slowly submerging. Given that it searches for prey with its eyes, riding low makes sense.

Are you my mother?

Although its eyes are well-adapted for focusing on underwater prey, they don’t appear to be useful in identifying offspring.

Like the wood duck, the merganser hen scouts out possible nest cavities. She gives a soft guttural call to her ducklings when it is safe to jump from the nest. Finally, the female merganser leads a parade of 10 to 12 precocial ducklings, some of which may not be hers.

This brood parasitism, as its called, can be wood duck eggs in a hooded merganser nest or vice versa. It can also be an egg from a hen of the same species that is dumped in another bird’s nest.

Nest box studies indicate that the frequency of egg dumping is not related to the availability but rather the visibility of boxes. That is to say, a box mounted on a post over open water is more likely to be parasitized than one hidden back in the woods.

On a serious note

Current events prompt me to close this essay with the opening lines of “Ducks,” a poem by F.W. Harvey. Harvey was an English poet and broadcaster who wrote this poem while being held as a prisoner of war in World War I.

From troubles of the world

I turn to ducks,

Beautiful comical things

Sleeping or curled

Their heads beneath white wings

By water cool,

Or finding curious things

To eat in various mucks.

• Mark Spreyer is executive director of the Stillman Nature Center in Barrington. Email him at stillmangho@gmail.com.