By Tom Dennis
Canvasback, Aythya valisineria
The Canvasback, one of our largest diving ducks, is a common year-round local duck that is easily recognized if you know what to look for. It has some unique features, including what may seem to be a strange scientific name but read on to see why it’s actually quite descriptive of the birds feeding behavior.
The genus name Aythya comes from Greek aithuia, an unidentified seabird mentioned by authors that include Aristotle. The species epithet valisineria comes from the wild celery plant Vallisneria americana. This aquatic plant is abundant in the St. Clair River and its tributaries and the winter buds and rhizomes (specialized root form) are the Canvasbacks preferred food during the nonbreeding period. The presence of this plant is a key factor in them remaining in our area during cold weather when they would typically migrate further south. Historically, the majority of these birds would migrate to the Chesapeake Bay but with its recent loss of submerged aquatic vegetation their range has shifted.
The common name is descriptive of the adult male bird’s back, sides and belly — having white with fine irregular lines resembling the weave of canvas. They can be quite easily distinguished from their genus cousin Redhead by the distinctive wedge-shaped head and bill on a long graceful neck. Their attire is completed with a chestnut red head and neck, black breast, rump, bill, and legs, and red eye. The female has the same distinctive head with dull gray to brown plumage.
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Canvasbacks breed and nest in prairie potholes in north-central states, throughout western Canada and into Alaska, preferring marshes surrounded by cattails and bulrushes that provide protective cover. They build a bulky nest with vegetation that they line with down. These beautiful diving ducks have a diverse diet that besides wild celery, includes other aquatic plants, snails and insect larvae. Because they strain the bottom mud as they feed, they are especially affected by lead poisoning from shotgun pellets in areas that are heavily hunted. Their population has fluctuated greatly over the past several decades and protection of natural waterways, breeding grounds, and safe hunting methods are crucial in survival of this species.
Canvasbacks are often seen at the Winter Bird Blast, jointly sponsored by Friends of the St. Clair River and Blue Water Audubon Society. The fifth annual popular event will be held on Saturday, February 23, 2019 and all ages are welcome to come learn and view this species and many other local winter birds. The indoor lesson followed by an outdoor fieldtrip start at 9:00 AM and will then be followed by a painting event at Studio 1219 where experts will help you create your very own masterpiece of the Common Goldeneye. I will also have a selection of my home-made glass bird feeders for sale with profits going to local conservation organizations.
Tom Dennis is a free-lance writer, passionate birder, zoologist, and naturalist.
Tom Dennis is a resident of Fort Gratiot where he and Laurie Melms Dennis, his wife of 45 years, tend to their bird and butterfly friendly gardens. He is a speaker and free-lance writer, passionate birder, advanced master gardener, creation scientist, and naturalist, with degrees from Michigan State University in Zoology and Biology. Tom is an active member of Blue Water Audubon Society, Master Gardeners of St. Clair County, Port Huron Civic Theater, Ross Bible Church, Tapestry Garden Club, Blueways of St. Clair, and is a steward of the Blue Water Riverwalk with Friends of the St. Clair River.