It’s Nesting Time for Bird Species on Mackinac
Nature Notes
By
Patricia Martin

It’s nesting time on Mackinac. Many of our seasonal feathered friends have returned to make their summer homes on the Island. Lately, I’ve been seeing different species collecting materials for building: grass, straw, horse hair, and twigs.

Birds build their nests out of many different, and often multiple, substances and in a wide variety of locations, from holes in trees and forks of branches to tangled shrubs and right out on the ground or beach. Look at the Sandpiper, whose nest is a ring of small stones. Some birds have even put the structures of man to work, like the Barn Swallows, which build nests under roof overhangs, or some of my neighborhood sparrows, which can be seen darting in and out of unused dryer vents with materials for nest building.

Female (left) and male Common Merganser

Many birds return to the same breeding site year after year, including familiar birds like the Goldeneye, Sandpipers, and Barn Swallows. The Bank Swallows used to nest here, until their sand banks were bulldozed. The advantage of going back each year to the same site is that the bird is familiar with the area and, therefore, there is a reduced susceptibility to predation. Some birds actually return to the same nest or colony year after year. Specific nest sites, however, may be used over time by a succession of individuals for reasons such as physical stability, protection from predators and bad weather, and closeness to a rich food supply.

Male Hooded Merganser

My neighbor asked if I had noticed that the mergansers had returned to their nesting site. I asked where the nest was, and he said in the unused chimney of the Inn on Mackinac. He said that they had nested there last year and he had seen them there again, though he hadn’t seen any young ones yet.

Mergansers are fish-eating, diving ducks with long, thin serrated bills. In flight, they move rapidly, with the head held straight and horizontal. There are three species of mergansers in North America, and all three spend their summers in our area. With the exception of the male Common Merganser, all three species have crests on their heads and a white wing patch.

The Red-breasted Merganser is one of the most common water birds in this area. They’re often seen along the east and west shores of the Island, followed by a dozen or more young. I wrote about them in a previous column. I do not believe that these were the birds nesting in the chimney, as they usually build their nests on the ground in a simple depression, well lined with vegetation, feathers, and down, and usually within 25 feet of the shore.

Both the Hooded and the Common Merganser are better candidates for the chimney nesting residence, as they both commonly nest in hollows of trees and may return to the same nest perennially.

The Hooded Merganser is the smallest of the three species, with a length of 16 to 19 inches and a wingspan of about two feet, and, ironically, it has the largest crest. The male’s crest is a vertical white fan bordered with black that can be raised and lowered during display. When the crest is folded, the head appears puffy. When swimming, the male’s white breast is visible, broken by two black strips. The female has a loose, rusty crest with drab brown and gray coloring. The song of these ducks sounds like hoarse grunts and chatters. When the male displays, he gives a rolling froglike “crrrrooo” and sometimes a hollow pop.

In the nests of the Hooded Mergansers, 10 to 12 eggs are usually laid. The females, however, will sometimes lay eggs in another female’s nest, resulting in dump nests of up to 36 eggs. The male often deserts the female early in incubation, and the female may share incubation duties with other birds, including Wood Ducks and Goldeneyes.

Hooded Mergansers are excellent divers, using both wings and feet to swim swiftly underwater. They predominately eat fish, however, they also feed on crustaceans, aquatic insects, other animals, and plants. These mergansers are able to fly quickly into the air from the water.

In the past, these Hooded Mergansers have been in decline, but their populations have recently been increasing, in part owing to the availability of nesting boxes, even those built for Wood Ducks. I’ve seen the Hooded Merganser along the shoreline every spring for the last four or five years.

The Common Merganser is the largest merganser in North America, measuring about two feet with a wingspan of nearly three. The male’s body is mostly white, with a dark head and red bill. The male has no crest, though the female has a chestnut head with a short ragged crest. The rest of the female is gray with a white chin. The song of the male Common Merganser is a harsh croak and the female, a loud, harsh “karr karr.”

Like the other mergansers, these birds are great swimmers and divers and enjoy pursuing small fish underwater. They also eat a variety of other underwater delicacies. These birds patter across the water or land in order to build up enough speed to take off.

Keep your eyes open along the lake for these three species of water birds and their young, which should be appearing soon. It might also be a good idea to check out unused chimneys and other such structures. You might just find a nest but, of course, do not disturb.

P.S. More wildflowers are beginning to bloom in the woods. I saw my first Yellow Lady’s Slipper blooming this week.

Trish Martin is a year-around resident of Mackinac Island, has earned a master’s degree in botany from Central Michigan University, and owns Bogan Lane Inn.