Red-winged blackbirds have already made their return to Maine, and are now being joined by other species like American woodcock in getting a jump on establishing their territory. Toby Talbot/Associated Press
EARLY WOODCOCK ARRIVALS
One of my favorite early migrants that has already begun returning to Maine is the American woodcock, well known for its nasal calls and aerial displays beginning at sunset on cool spring nights. Every year we get a handful of early sightings, and the usual question in tow is “will they be alright?”
This is a valid concern for a shorebird, especially with several inches of snow on the ground, so let’s look at how these birds survive and why they show up so early.
First, keep in mind that American woodcocks are short-distance migrants. Unlike many of the shorebirds we see in Maine – who are wintering as far south as the southern half of South America – woodcocks mostly winter in the United States. Since they are already so close, they can react to changes in the weather and come north on warm late-winter days. Those long-distance migrants, on the other hand, are relying on photoperiod, the amount of daylight in the day. As the photoperiod gets longer, it signals to sandpipers and plovers to start the long journey north. But woodcocks just need a little warmth to trigger their migratory urge.
There is a huge benefit to the birds that are willing to risk moving early: less competition. The earlier that males can move into the wet fields where they’ll perform their splendid courtship display, the more likely they are to get a mate. This is a high-risk, high-reward venture. It is very risky to migrate early because of the chance it will snow again, or be too cold, and the birds won’t be able to find food (since they are typically probing that cold ground for invertebrates). The high reward, though, is higher reproductive rates.
Red-winged blackbirds are another species we see taking their chances on this. I’ve had ambitious male red-winged blackbirds singing from the tops of the maples around my yard for more than a month now. Blackbirds are much easier to detect than woodcocks, so hopefully one you’ll be able to study yourselves. The blackbirds also have the option of turning to your bird feeders if food is scarce. Still, woodcocks are opportunists, and we often get reports of them feeding around the warm foundations of houses when snow is covering the fields they would normally prefer.
WHO’S BEEN HIBERNATING?
When I recently told a friend that I had seen two skunks running around in my yard after a big snow storm, they remarked “I thought skunks hibernate.”
Then, the next day, as I drove into Maine Audubon’s Gilsland Farm sanctuary in Falmouth, an Eastern chipmunk was sitting atop the newly piled snow, and my first thought was “an early riser!” So I thought it would be fun to give a quick rundown of the different winter survival techniques used by Maine’s mammals, especially as we happily (hopefully) see more of them as winter comes to an end.
First, the most passive way to survive the winter is to hibernate. I do envy this technique. Spend a few months eating a bunch of food to build up fat reserves, then sleep during the shortest, coldest days until food becomes plentiful again. Sign me up! The myth to dispel here is how few mammals actually hibernate in Maine: five species of bats, two species of jumping mice, and groundhogs. Of the eight total bat species we have in Maine, three migrate south in the winter, while the others – big brown bat, little brown bat, Northern long-eared bat, Eastern small-footed bat, and tri-colored bat – all hibernate in caves. Those hibernating bats are the ones that, unfortunately, are suffering huge population declines because of the spread of white-nose syndrome (in which a fungus prevents them from successfully hibernating and makes them unable to survive the winter).
Black bears hibernate, though, right? Actually, strictly speaking, a “true” hibernator goes through a series of metabolic suppressions, including lowering body temperature, heart rate and respiratory rate. Bears, however, keep their body temperatures fairly high. This is especially helpful for the females that are giving birth while in the dens.
Other mammals often thought of as hibernators, like the skunk mentioned above, instead will go through a series of short torpors, or deep sleeps. Raccoons and chipmunks fit in this category, too. That’s part of the reason why we don’t see many of them in the winter, though they do sometimes appear on warm days or nights; you can smell how active skunks are. Eastern chipmunks also live mostly underground, surviving on the food they cached last fall, but they will journey to the surface to resupply.
Hopefully this helps clear up some of the often misattributed winter survival techniques that Maine’s mammals go through to survive Maine’s deep snow and cold temperatures, and gives us all an appreciation for the amazing adaptations they’ve developed.
Have you got a nature question of your own? Email questions to ask@maineaudubon.org and visit maineaudubon.org to learn more about birding, native plants, and programs and events focusing on Maine wildlife and habitat. Doug and other naturalists lead free bird walks on Thursday mornings, 8 to 10 am in March (7 to 9 am starting in April), at the Gilsland Farm Audubon Sanctuary in Falmouth.
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