By December, the feeling of winter has truly set in at Fresh Pond. All the deciduous trees around the pond have dropped their leaves, save the most stubborn oaks and beeches, some of which will hold onto those leaves through the winter. The greenest things you’ll see on a walk around the pond are most likely the lichens and mosses that grow on tree trunks. Almost every arthropod living around the pond is either dead, underwater, or well-hidden and hunkered down for the winter. Amidst this stillness and deadness, though, some of the year’s highest ecological dramas are playing themselves out. The animals that remain active throughout the coldest months have developed remarkable adaptations to these harsh conditions. Birds like chickadees and kinglets experience dramatic daily fluctuations of both body temperature and weight. Chipmunks and squirrels work through their vast stores of nuts and seeds. The region sees an influx of winter residents, who have migrated from further north. You’ll be rewarded for paying attention to any scale of the ecosystem in the winter at Fresh Pond, whether observing the slow work of saprophytic fungi or the soaring flight of the red-tailed hawk.
“Observing the changes in nature and the rest of our environment throughout the seasons is one of the most joyful things about living in New England. Whether I’m taking in a buzzing bee metropolis on a patch of goldenrod, breathing steam on a walk around an iced-over pond, or feeling the air come alive on our first warm spring day, I’m always happy when I’m observing nature’s changes like this. These natural rhythms give us a place to find solid ground, whatever we might be going through.”
EwA citizen scientists and interns survey the Lusitania meadow 📍 for arthropods every single week during the warm seasons. During the colder months, we explore the general biodiversity of the reservation in more detail. This gives us the opportunity to get to know the meadow and its surroundings intimately. Each week highlights different relationships between the plants and their visitors—fascinating stories unfold. This almanac is a wonderful means to share with our communities what we observe and record at Lusitania over the course of the year.
📅 Once a month, we open EwA documentation sessions to the public. Check us out on Eventbrite and come experience with us the magic of this wonderful meadow—an oasis in the middle of a very busy city.
The arrival of December signals the imminent approach of the winter solstice, the shortest day of the year, on December 21. The variety of traditions and celebrations surrounding the solstice that takes place across the world serves as a reminder of how completely these slow natural rhythms influence our lives. The observation of the solstice dates back at least to the neolithic; the main axis of Stonehenge points toward the place the sun sets every year on the shortest day. While we’re lucky that this time of year no longer signals such a perilous season of food scarcity and starvation, it’s important to take a moment and reflect on how completely our experience still changes in these dark months. Many of us feel it quite viscerally around now, with twilight long gone before dinner is even on the stove. Any chance to recognize this occasion, whether it’s a short, mindful few minutes or a full celebration, represents time well spent.
While the 21st is the shortest day, neither the latest sunrise nor the earliest sunset occurs on the solstice. Due to a geometric quirk in the apparent path of the sun, the earliest sunset (4:12 PM) will be a couple of weeks before the solstice, on December 7, and the latest sunrise (7:13 AM) won’t occur until January 3. The solstice is simply the day in between those two dates on which the total minutes of sunlight are fewest. By the end of the month, sunset will already be getting a minute later every day, and each passing day will bring a larger difference than the last.
The warmest Boston gets in December in an average year is a monthly maximum of 16.3ºC (61.3ºF). The low temperature of the month, on average, is -11.6ºC (11.1ºF). The average daily high temperature throughout December in Boston is 5.1ºC (41.2ºF), and the average nightly low is -2.1ºC (28.2ºF). Frost is frequent throughout December in Boston, and it is the first month with the potential for lasting snowpack, with 23cm (9.0 in) of snow each year on average. A thin film of ice might form on Fresh Pond throughout parts of December, but not usually the thick layer of ice that gave the pond its place in history as part of a vast ice harvesting empire in the 19th century.
Ducks to Watch out For: Ring-necked Ducks on the Pond
A regular winter inhabitant of Fresh Pond is the Ring-Necked Duck (Aythya collaris), a diving duck. Male ring-necked ducks are identifiable by the white ring on the bill, the angular shape of the head, and a white triangle on the breast appearing in front of the duck’s wings when folded. Female ring-necked ducks, while drabber and harder to distinguish from other ducks, can also be identified by their banded bill and angular head. The eponymous ring around the duck’s neck is very hard to make out from a distance, as the name was given by naturalists who had the advantage of examining dead specimens up close.
Ring-necked ducks often flock with other Aythya diving ducks such as Lesser Scaups (Aythya affinis) and Redheads (Aythya americana), but this behavior is seldom seen on Fresh Pond. Ring-Necked Ducks are the only diving ducks that prefer inland lakes and ponds as their habitat, which might explain why Fresh Pond’s flocks are so exclusive of other species.
Massachusetts is at the upper limit of the ring-necked duck’s winter range, meaning this is the furthest north in the region that you’re likely to see the ducks staying through the winter instead of passing through. Like many North American birds, the winter range of the duck is likely to shift northward as the earth warms and northern winter conditions become more hospitable.
Ring-necked ducks make shallow dives to feed at the bottom of whatever body of water they inhabit. The ducks are omnivorous, consuming different proportions of plant and invertebrate matter depending on the time of year and developmental stage of the duck. In the winter, ring-necked ducks feed predominantly on aquatic plant material like the seeds and rhizomes of water lilies, sedges, and arrowheads. Heavy consumption of the dragonfly larvae, earthworms, caddisflies, and mollusks that make up the animal portion of their diet is largely reserved for breeding females and young chicks. Ring-necked ducks swallow mollusks whole, and their shells are later crushed in the bird’s gizzard. Ring-necked duck chicks are completely dependent on an invertebrate diet.
The population of ring-necked ducks at Fresh Pond is substantial and easy to notice starting in November and continuing throughout the winter. Multiple small flocks of around 3-10 ducks can typically be observed on a walk around the pond. It’s easy and fun to watch their feeding behavior and interactions with each other – be sure to look out for them on your next visit!
Hibernation and Torpor
Every organism that relies on a certain range of temperatures to maintain its metabolism is deeply affected by the onset of winter’s harsh conditions. That’s a long way of saying that every member of Fresh Pond’s ecosystems has to adjust in some way to the cold temperatures that come with December and the months after. Of these adaptations, perhaps the most familiar is hibernation, a seemingly easy-to-define behavior that manifests as a long period of winter inactivity.
As the great naturalist Bernd Heinrich points out in a 2003 article for Northern Woodlands, the true definition of hibernation is a little harder to pin down. Many different species go through long periods of inactivity through the cold winter months, and not all of them are technically hibernators. The only “true” hibernators are those mammals that enter long periods of torpor, a state in which the animal takes on significantly lowered body temperatures and an almost completely halted metabolism, punctuated by short episodes of arousal from said torpor. The inactivity that befalls cold-blooded reptiles and amphibians throughout the winter months is called brumation, not hibernation, and comes with a set of metabolic processes that distinguish it from hibernation. The halt in development that arthropods experience through the winter is called diapause, as insects are not “true” hibernators either.
Even within the “true” hibernators, there is a wide range of hibernation states. Bears hibernate at a body temperature (34ºC, or 93ºF) far higher than most other hibernating animals, and some ground squirrels and some closely related animals differ completely in whether they hibernate or not. Take the squirrel family, Sciuridae, for example, which includes gray squirrels (Sciurus carolinensis), chipmunks (Tamias striatus), and groundhogs (Marmota monax). (Did you know that groundhogs are technically squirrels? Now you do.) Tree squirrels such as gray squirrels do not hibernate at all, although their average body temperature lowers slightly throughout the winter, and are active all year long. Gray squirrels adapt to winter conditions by continuing to collect food and sharing body heat with other squirrels in their dreys (squirrel nests) or tree cavities.
Ground squirrels like chipmunks and groundhogs, on the other hand, enter deep hibernation. When chipmunks are in torpor during hibernation, their body temperature drops as low as 6ºC (43ºF), and their heart rate falls from about 400 beats per minute to somewhere in the mid-20s. Groundhogs’ body temperatures can dip even lower, to 2ºC (35ºF). In these conditions, the typical metabolism of the animal is almost completely absent. Though hibernation may look a lot like sleep, deep torpor precludes the many important maintenance processes an animal’s body performs while truly asleep. Torpor is “a sleep so deep that it no longer involves sleep.” As such, a hibernating chipmunk or groundhog must temporarily rise out of its torpor to sleep from time to time! Chipmunks also usually eat some of the thousands of seeds they have stored in their burrows during these periods of arousal.
Hibernation is hardly a shortcut through the hardships of winter – it’s an extremely taxing survival technique. It requires an animal to basically enter a controlled coma in response to extreme food scarcity. Chipmunks and groundhogs can lose up to half their body weight throughout hibernation, and the slow violence of torpor can even cause brain damage. Next time you’re walking by Lusitania Meadow, or the chipmunk burrow by your front step, take a moment to appreciate the slow, perilous, immobile feat being undertaken by rodents a few feet below.
Frigid Fungi: Spotlight on Turkey Tail
One of the most common and conspicuous fungi that you can spot at Fresh Pond in December is the turkey tail (Trametes versicolor). Turkey tail is a medium-sized polypore that grows on decaying wood and looks like the flared tail of a tom turkey — hence its name. It can be identified by its bracket-like shape, abundant fruiting bodies, and contrasting bands of rusty reds, oranges, or browns. The false turkey tail (Stereum ostrea) can look quite similar, but the two can be distinguished in the field (see the Nature Quest further down).
Turkey tail is a saprophyte, meaning it grows on dead organic matter. More specifically, turkey tail inhabits dead or wounded hardwood. The fungus breaks down and digests the lignin of deadwood. Lignins are the substances that give woody plants their stiff, “woody” quality. Once the lignin has been broken down by a fungus such as a turkey tail, only the cellulose remains in the dead plant cell walls. This remaining cellulose is white in color, and thus the type of rot caused by turkey tail is called white rot.
The polypore you see on the outside of the log is the fruiting body, or reproductive organ, of the fungus. The rest of the organism is inside of the log, in the form of hyphae – tiny strands of cells – which exude enzymes to break down the wood’s lignin. Mycologist and friend, Larry Millman, tells us that there’s a reason why one sees so many turkey tails grouped together on a log but doesn’t see any other fungi. It’s because the turkey tail’s mycelium releases powerful enzymes that ward off or kill the mycelia of other fungi growing inside the same woods. These enzymes say ‘This food is mine!’
The fruiting bodies of turkey tail don’t always overwinter, but they’re certainly capable of doing so, and that is why turkey tail is often so visible in winter! At Fresh Pond, you can be sure to spot some turkey tail, along with other saprophytes, on a large dead tree near Butterfly Meadow.
🔎 Nature Quest » Learning the Difference Between False and True Turkey Tail
On the face of it, a false turkey tail and a “true” turkey tail look incredibly similar. Both grow on damaged or dead hardwoods and display vivid bands of red, orange, or brown color. There is one key, consistent difference between the two, though, and it has to do with the fungi’ role as a reproductive organ. Different species of fungi bear a wide variety of spore-bearing surfaces.
“True” turkey tail is a polypore, meaning that its underside consists of pores. False turkey tail has no such pores. So if you’re stumped on whether the turkey tail you’re looking at is false or true, just get a little closer to the ground and have a look at its underside! If it has pores, it’s a “true” turkey tail. A mirror can be a useful tool in examining the underside of mushrooms, too.
The winter brings fresh adaptations, heightened stakes, and new ways of seeing to a naturalist’s walk at Fresh Pond. A field that once buzzed with pollinators is now only moved by wind and the occasional bird. The chipmunks that once scurried the forest floor are weathering the harshest months of the year underground in deep torpor. Even if you’re in the midst of your own sort of hibernation this December, it’s well worth the trip to Fresh Pond to stay in touch with the slow pulse of the ecosystem. Whether you see a duck dive beneath the frigid water or a mushroom holding on through the cold, you’ll always find something worth being curious about.
Enjoy your visit. 📅 Join our monthly Fresh Pond Wildlife Documentation Walk. Share your findings with us (you can comment below)! We will be back next month with a new slice of life in the meadow.
EwA Useful Links
📖 Fascinating Fungi of New England (2011) by Larry Millman (Author)
📖 The Book of Swamp & Bog: Trees, Shrubs, and Wildflowers of Eastern Freshwater Wetlands (1995) by John Eastman (Author), Amelia Hansen (Illustrator)
December, 7th 2020 | by Mike McGlathery
Editing & layout by Claire O’Neill. Thanks to Larry Millman for reviewing ‘Spotlight on Turkey-tail’. Banner picture © Claire O’Neill. All the in-text species photos in this article are visual records that the EwA team collects at our various study sites, including at Fresh Pond. Click on any picture and you will land on the record and its owner. Photos are licensed under Attribution-NonCommercial (CC BY-NC). See EwA’s biodiversity occurrence records specific to this place in the EwA at Fresh Pond iNaturalist project.
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