Volant. P.A. – You can find them paddling on the Black Swamps near Volant or even wandering around Lake Britain if you’re lucky. These two places provide the water and cover they need for nesting. The large crest on their heads and their golden-yellow eyes are dead giveaways for identifying the Hooded Merganser, a member of the duck family that Audubon says is the only species in this habitat that eats fish. The Tweetspeak class’ adventure to the Volant Strip Grasslands and Black Swamp gave us our first official look at the merganser on the water.
The Hooded Merganser has a black crest with a distinct white patch on the sides. Those white patches are only found on adult males. The patches can vary in size depending on whether the crest is raised or lowered during courtship of a mate. Regardless of the size the white patches are abundantly prominent. A quick review of my Sibley Field Guide to Eastern Birds of North America revealed the immature males will not have the white patches.
Ornithologists and birders use plumage and patterns to identify the species and even the sex of the bird. The Hooded Merganser female feathers are dark brown and gray with some warm color feathers on their heads they also feature a prominent crest, but not as splashy as the male’s.
When it came time to identify the male’s case, it is identified by its majority black top with its white breast and its rich chestnut flanks. The males have one characteristic that makes them stick out like a sore thumb, their bright-fluorescent yellow eyes. They are easy to spot since the head is majority black.
So why is the merganser’s head so fancy? The Cornell Lab reports pattern and color variations are often based on the sex of the bird while also influenced by age, the time of year or even molting. In the merganser, it is clear that this is a form of sexual dimorphism. Even the yellow color of the male’s eyes show this form of dimorphism as the female’s eyes are a dark brown color.
I feel very lucky I was able to witness this species in the wild. I learned from my guide it is the smallest of three species of merganser that are year-round residents of Pennsylvania. Audubon also reports the species numbers were in decline in past decades, but recently has rebounded in numbers. Audubon credits that to the use of artificial boxes. Spotting this bird was a great success for me as a birder and I am privileged to have seen it.