For the Birds Radio Program: Hooded Merganser
Early every spring there is a brief window of time when Hooded Mergansers bring elegance and style to wooded lakes, ponds, and streams. This is the time to get out and enjoy them. Although this species is a reasonably common nester in the north woods, the males seem to disappear altogether by mid-spring, and handsome as they are, that handsomeness is infinitely enhanced by the head-bobbing and crest raising they do in their twitterpated state in spring. Hooded Mergansers are biologically something of a transition species between Buffleheads and other mergansers, and share many behaviors with Bufflehead, including some of their courtship rituals.
Hooded Mergansers nest in natural cavities and fairly large woodpecker holes. Their eggs are unique in being almost perfectly spherical, with an unusually thick shell. As is the case with many cavity nesters, Hooded Merganser eggs are pure white. Inside dark cavities there is no value in cryptic coloration, and white may make the eggs visible enough to protect the eggs from being accidentally crushed when a female rushes back in to incubate.
From early accounts it seems almost certain that this species nested in virtually every wet wooded area in the eastern and mountainous western United States. But habitat changes associated with settlement occurred so long ago in so many parts of the east and northeast that Hoodies had become scarce or eliminated as breeders by Audubon’s time. And eastern populations fell precipitously in the forty years prior to 1925, primarily because logging of old forests eliminated nesting cavities, and also because of the birds’ unwary nature around hunters—the Migratory Bird Act was one of the reasons they’ve survived. Hoodies aren’t as fishy tasting as Common and Red-breasted Mergansers but aren’t particularly good eating, especially compared to Wood Ducks. So back then people wouldn’t have done a lot to help them despite their dangerous decline, but fortunately Hooded Mergansers benefitted from nest boxes set out to save Wood Ducks, which had been extirpated from many areas for the same reasons Hoodies had. Hooded Mergansers today are exceptionally wary and reclusive, which is partly why they’re so difficult to spot, though their wooded habitat contributes to that, too. Nowadays breeding Hoodies occur throughout most of their ancestral range, although populations are small and localized. Fortunately for northlanders, they are most abundant in the Great Lakes region.
When I lived in Madison, Wisconsin, I used to get up at 4 am every spring morning to go birding before I went to the school where I taught junior high. Unfortunately, the park I went to didn’t open until 7 am. I never thought about how I’d been breaking the law until the morning I was watching some courting Hooded Mergansers as a policeman suddenly approached. I looked up from my scope when I heard his footsteps, blurting out before I realized that he was there to kick me out that here were some displaying Hooded Mergansers. He looked through the scope and his face broke into a huge smile. “Wow!” he said, and told me that he saw Hoodies during hunting season, but had never seen them courting before. He didn’t kick me out, and throughout the rest of that migration season he stopped by now and again to ask what birds I’d been seeing. Just one more example of the importance of birds when dealing with legal issues.