Plants and Animals

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From Missouri Conservationist: Dec 2011

Common Merganser

Winged master anglers, these diving ducks can be seen fishing Missouri’s big rivers this month.

Every winter I head to my favorite location along the Upper Mississippi Conservation Area in St. Charles County to photograph common mergansers (Mergus merganser). When I discovered the spot a few years ago, I was actually searching for American white pelicans. I was delighted to find both species at the site. After returning for four years, I’ve decided it is no coincidence that pelicans and mergansers are often found together. I’ll explain later.

The common merganser is a large, slender diving duck with a burnt orange, serrated bill that it uses to catch fish. The drake has an iridescent green head that is darker than that of a mallard, more of a forest green, with dark eyes that are barely visible. Its body is brilliant white with a gray back and tail and white wings with black primary feathers. The contrasting colors of the male merganser are a formidable challenge to wildlife photographers, even in good light. The female common merganser has more reserved coloration but is as beautiful as the male, in my opinion. The hen’s head is rusty with matching eyes and a backswept crest. The feathers of the wings and body are gray, fading to white on the breast and lower neck. Its flanks and chin are white.

Common mergansers winter in Missouri and are found along our larger rivers and reservoirs where they feed on fish, mollusks, crustaceans, frogs and even small birds and mammals, given the opportunity. Nesting is far north of Missouri, mostly in Canada, where mergansers line a tree cavity with down and produce a clutch of up to 15 eggs. Young leave the nest a few days from hatching and begin diving for aquatic insects under close scrutiny from their mother. Later they begin feeding on fish and larger prey. The common merganser population is stable in North America and while they are not considered a fine table duck, mergansers are legally hunted in Missouri during waterfowl season.

So why would pelicans purposefully mingle with mergansers? The answer is to steal food! I’ve watched the two species together for hours as the mergansers, master anglers of the avian world, dive for fish and surface with quivering prizes, their glory short-lived as a cadre of huge pelicans attack and steal every scaly morsel. Pelicans are apparently smart enough to know that mergansers will catch fish with aplomb, and they are ornery enough to plunder free meals at every opportunity. At first, I wondered why mergansers stuck around in such annoying conditions, but I soon realized that it didn’t matter because the pelicans simply followed them wherever they went. As you can see from the healthy individuals in these photographs, these beautiful divers do find a way to swallow a meal or two during daily smackdowns with their pouch-billed rivals. Such is the life of the common merganser at a special place on the Mississippi River.

—Story and photo by Danny Brown

This Issue's Staff

Editor In Chief - Ara Clark
Managing Editor - Nichole LeClair Terrill
Art Director - Cliff White
Staff Writer - Bonnie Chasteen
Staff Writer - Jim Low
Photographer - Noppadol Paothong
Photographer - David Stonner
Designer - Stephanie Thurber
Artist - Mark Raithel
Circulation - Laura Scheuler