Get to know your invaders. Just because this invasion season is starting a little slowly doesn’t mean you won’t be invaded. You will.
Birds go south in the winter. It’s hard for some people to fathom that Maine is south, relatively speaking. We have our regular snowbirds that come down from the arctic in predictable numbers. American tree sparrows show up every winter, often foraging under feeders. Then we have our irregulars. Redpolls may invade one year, then be totally absent the next.
Maine’s summer residents head to the same places every winter, usually in the tropics. Some go all the way to the southern tip of Argentina. But our arctic invaders are not nearly so predictable. They’re accustomed to freezing weather, so they wander south only to find food and relief from abnormal chill. During a mild winter, they may never venture south of the Canadian border at all.
Moderate temperatures this year have kept things rather quiet around here. That can change at any moment. An arctic blast will send many Canadian birds scurrying to the lower 48. Even if winter stays mild, some will exhaust the food supply farther north and look for greener pastures here.
Bohemian waxwings almost always show up sooner or later. Be on the lookout for this invader among crab apples and ornamental berries. I usually spy a few while Christmas shopping, but the only ones I’ve noted so far this year were up in the woods west of Baxter fully two months ago. There were three. Later in winter, they can gather by the thousands.
Pine grosbeaks are another fruit eater that devours our berries in winter. I haven’t seen any this year, even in their favorite spots. Two years ago, they arrived before the maples had turned red, then were totally gone again by New Years. Last year they came late, with hundreds flooding the University of Maine campus in early February. It all depends on the availability of food and reasonable weather up north.
I invite you to share my winter fun in watching small finches. American goldfinches, pine siskins and common redpolls are closely related. Goldfinches and siskins nest in Maine. Redpolls are subarctic breeders, with a tendency to invade southward. These three species often associate because they like the same small seeds and the advantages of safety in numbers.
Every winter, the mix of these three species is different. Cold weather drives the goldfinches to Massachusetts. Colder weather drives the siskins there, too. But cold weather draws the redpolls here. In changeable weather, mixed flocks of all three can start nibbling on your Nyjer seed in the thistle feeder. It’s a good way to judge how winter is progressing.
The first half of December was mild. Under such conditions, there is plenty of natural food in the woods, and small finches don’t visit feeders very much. Over the first two weeks of this month, I’ve only had a few goldfinches show up at the feeder. However, when I walk around my neighborhood, I can actually hear them up in the treetops, and I can pick out the buzzier sound of a few siskins among them. My feeders are fully stocked, waiting for the inevitable snow that will drive them to my backyard.
I haven’t seen one yet, but I’ve been expecting redpolls. A phenomenon occurred just north of us in late October. The Tadoussac Bird Observatory in Quebec reported a record number of redpolls flying by in a seven-hour span. They tallied 15,790 redpolls on Oct. 26. That beat the old record by more than a thousand. Most redpolls will stay above the St. Lawrence River, but some are bound to come this way. The Observatory is only about 50 miles away from our border. In fact, a few redpolls have already been meandering around Aroostook County.
Snowy owls are definitely invading. Several have been witnessed in The County. They’re on mountain tops in Acadia. And several have been tallied in southern Maine, including two at the old Brunswick Naval Air Station. I’m not expecting the huge influx we experienced over the last three winters, but they won’t be rare, either.
I saw only one northern shrike all last winter. They should invade in bigger numbers this year. I’m also expecting more crossbills. Numbers have been low recently, but the spruce cone crop has rebounded and it’s only a matter of time until they also invade us again. Bring it on.
Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at mainebirdingtrail.com. He can be reached at duchesne@midmaine.com.