by Sally Stockwell
Just like human snowbirds, many of “our” birds head south for the winter. They breed here in Maine or pass through Maine on their way to breed even farther north, then head to warmer climes for many of the same reasons—it takes less energy to stay warm, the days are longer, and there is ample food of all kinds. Even some bats and insects migrate south for the winter, such as the Eastern Red Bat, Monarch Butterfly, and darner dragonflies (yes, dragonflies—who knew?). Then there are the true snowbirds that visit us each winter, coming south from the Canadian taiga and tundra.
Let’s take a closer look at a few of these winged critters and follow them on their amazing journeys. Where do they go? What do they do when they’re gone? Come with me on an armchair travelogue from the warm confines of your winter home. Let’s start at the northern tip of Maine and work our way south.
Forests
Blackpoll warblers breed in wet black spruce and tamarack forests that stretch from northern Maine, across Canada, and up to Alaska. I first met Blackpoll Warblers when I was conducting breeding bird surveys in peatlands of Maine. They liked the black spruce forests with wet feet that formed a ring around bogs, and I loved listening to their wispy song and trying to find them grazing on insects on the spindly branches of the trees. Their coloring matches the trunks of the stunted spruce so they are very hard to find.
Most Blackpolls migrate south to the coast of Maine or Maritimes before jumping off and flying nonstop more than 1800 miles to overwinter in either the Caribbean or northern South America, east of the Andes. The trip takes them about 88 hours, so they need to double their weight before heading south. Imagine all the energy needed to make that flight!
In the winter they can be found in forest edges and second-growth forests below 10,000 feet, and during migration they stop in mature evergreen and deciduous forests. Habitat loss is shrinking their wintering grounds; and logging and other extractive industries, plus climate change, threaten their boreal breeding grounds. That’s why Maine Audubon is working with forest landowners, foresters, and loggers to improve breeding habitat for Blackpolls and other forest birds of conservation concern through our Forestry for Maine Birds program.
Five of Maine’s bats hibernate in large groups in caves. However, tree bats—or those that roost hanging underneath leaves and nest singly or in small groups in tree cavities or under the bark of trees—do not hibernate in caves for the winter, but migrate to southern parts of the U.S. and then hibernate, hiding in hollow trees or under leaf litter. There are three tree bats in Maine: Hoary Bat, Silver-haired Bat, and Eastern Red Bat. Eastern Red Bats mate during the fall migration, and females give birth the following spring. Little is known of their actual migratory pathway or final wintering range.
Forests cover more than 95% of the state, but tucked among those forests are many streams, wetlands, ponds, and lakes, so let’s take a look at some of the migratory species that breed in those habitats as well.
Streams and Wetlands
What could be more thrilling than to see a Wood Duck swimming and flying along the course of a river? These birds favor streams, swamps, marshes, beaver ponds, and floodplain forests, with ample vegetation along the shore for finding food and hiding from predators, and adjacent to upland forests for nesting. Contrary to popular notions, they do not nest only in wood duck boxes, but in natural cavities in larger, older trees—sometimes more than a mile away from water. Wood ducks in Maine and Canada migrate to the southern U.S. or Mexico for the winter, but in other parts of the U.S. where the water doesn’t freeze, they can be found year-round.
Moving to saltwater, one of the hidden gems that makes its home in salt marshes along Maine’s coast is the Saltmarsh Sparrow—a cryptic bird that nests in the high marsh grass and is accustomed to being occasionally flooded by high tides. When that happens, the young climb up on the tall grasses around their nest and take refuge until the tide subsides. Lately, with sea level rise, that trick doesn’t always work, so Maine Audubon is working with biologists who are experimenting with building floating nest platforms. Saltmarsh Sparrows migrate south along the Atlantic coast, stopping in salt marshes along the way, with some wintering in Florida or the Gulf Coast.
By now, most everyone has heard about the amazing migratory journeys of the Monarch Butterfly, but did you know that some dragonflies also have a multi-generational, migratory lifestyle? A recent study documented the Common Green Darner migration, which involves at least three generations that travel 400 miles from their southern to northern ranges and back each year. The young spend most of their time in the water as dragonfly nymphs, and only a short time flying around as adults, when we are most likely to see them.
Lakes
When most Mainers think of loons, they think of haunting wails and young chicks riding on parents’ backs on our freshwater lakes and ponds during the warmer breeding months. But did you know that these same loons normally winter in ocean waters off the Atlantic coast? They actually spend more of their life on the ocean than on freshwater. In the frosty months, you’ll often find Common Loons socializing in groups and eating seafood meals including crabs, flounder, and herring. Because our lakes freeze, Common Loons normally migrate in late fall to salty waters including coastal bays and coves, sometimes even frequenting areas up to 60 miles offshore in New England’s coastal waters. Some of Maine’s breeding loons do travel farther south, however, to wintering sites in New Jersey, Maryland, and beyond. Wherever they travel, most will return to the same four to eight square miles of ocean every winter.
Grasslands and beaches—though they are not extensive in Maine—are of particular interest to us. Most of our grassland birds have shown dramatic declines in recent decades and the only shorebird that nests on our beaches is endangered. Helping these species during breeding and migration is an important conservation goal for Maine Audubon and many other organizations.
Grasslands
Like other grassland birds—those that used to nest in the tallgrass and mixed grass prairies of the central and western U.S. and Canada—Bobolinks now nest in large fields, meadows, and hayfields across the northern U.S., including in Maine. They have a bubbly song that rises with them above the field grass, and they feed on seeds, insects, and spiders. After breeding, they move to marshes to molt before flying in groups across Florida and the Gulf of Mexico, making a long stopover in Venezuela, then settling in south of the equator in Bolivia, Paraguay, and Argentina for the winter—an annual round trip of more than 12,000 miles!
Beaches
Many shorebirds such as the Semipalmated Sandpiper migrate through Maine on their way to nesting areas in the Arctic and wintering areas in the Caribbean and Central and South America, but there’s only one that nests on the beaches of southern Maine: the Piping Plover. Piping Plovers make a scrape in the sand for a nest, typically lay four eggs, and usher their chicks around the beach searching for insects and other invertebrates in the seaweed rack and mudflats. In late summer, they depart. But to where?
We are still learning more every year about Piping Plover migration and wintering habitat. Many of them winter on remote sandy cays that are expansive and difficult to access. In 2012 about ten percent of all the Atlantic Coast population of plovers was observed at Joulter Cays in the Bahamas—a new discovery. Now, through an intensive collaborative conservation effort, the area is on its way to becoming a National Park partially due to these recent discoveries. Nesting Maine plovers have also been found wintering in South Carolina and Georgia.
The true “snowbirds” — birds that move south into Maine from northern Canada to spend their winter with us—are some of my favorite birds, as they love northern winters as much as I do.
Snow Buntings, Snowy Owls, and more visit us each winter from the Canadian taiga and tundra. I’ve seen Snow Buntings whizzing by in the wind on the top of Katahdin and foraging in the snowy hayfields near my home in southern Maine, and I always stop to marvel at their small size but tough nature. They remind me of the many wonders and challenges of traveling in the high Canadian Arctic where they breed, making a nest in rock crevices lined with moss, grass, fur, and feathers to keep the young warm. They feed on grass and flower seeds, insects, and spiders.
Other snowbirds include Lapland Longspurs, Dark-eyed Juncos, Common Redpolls, and Bohemian Waxwings. Often these birds travel in flocks, searching for food and avoiding predators by sticking together. These are the birds you should be looking for this winter at your feeder or when you are out walking, skiing, or snowshoeing. They will keep you company, bundled up against the cold, ready to embrace all of winter’s glory.
Sally Stockwell is Director of Conservation at Maine Audubon. She is a wildlife ecologist with a Ph.D. from the University of Maine and over 40 years of conservation education and action in Maine. She has worked as a naturalist, outdoor adventure leader, and environmental education and college instructor in Maine, Minnesota, the Western and Southwestern US, and Alaska. Sally remembers first visiting the extended Stockwell family at Keoka Lake as a young girl from St. Paul, Minnesota and relishing the clear water, the smell of the pines, and the freedom of running through the woods. She has visited ever since, and was fortunate enough to bring her own two children into the family fold while raising them in Cumberland, Maine.
This article is reprinted with permission from Maine Audubon and was originally published in the Winter 2021-22 issue of Habitat Magazine.
Online extra: For an expanded version of this article with more species, visit https://maineaudubon.org/snowbirds/
Blackpoll, Common Loon, and Piping Plover photos courtesy of the Maine Audubon Society. Eastern Red Bat photo courtesy of NH PBS. Wood Duck photo courtesy the Maine Bird Conservancy. Common Green Darner photo courtesy of Science News. Saltmarsh Sparrow is courtesy of Bri Benvenuti, US Fish and Wildlife Service.
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