I recently had an experience while snowshoeing which I have always hoped to have, but which has escaped me during all these years of tromping through the woods. I was following the tracks of a Ruffed Grouse and all of a sudden it exploded out of the snow about two feet in front of me as it left its night time shelter. Now that we have over ten inches of fluffy snow, grouse can dive into the snow and spend the night in their self-made snow roosts. Finding a grouse’s snow roost is a relatively common experience; being startled by a grouse exiting one is not.
Diving head first into the snow, the grouse works its way anywhere from three to ten feet, creating a 4-inch-wide tunnel through the snow before it hollows out a small cavity and settles down for the night in its own little igloo. Up until recently, a hard crust prevented grouse from seeking shelter this winter in this manner. Had temperatures been very cold, many grouse would have suffered and even perished under these conditions. Fortunately, they can now roost in the snow, where temperatures are much warmer (as high as 32°F.), and rarely fall below 20°F. regardless of how cold it gets outside. Not only do these roosts hide the occupants from predators, but they provide an energy savings of 30 percent or more for grouse.
(Photo: Snow roost entrance hole (nearest the bottom of photo) where a grouse dove into the snow, and the exit hole (nearest top of photo), three feet from entrance hole, which a Ruffed Grouse created when it exploded out of its roost. If you look closely at the exit hole, you may be able to detect wing marks.)
At this time of year one would expect to find Leopard Frogs lying on the bottom of a pond, partially but not completely covered with leaves or mud as they hibernate their way through winter. Because of the depth of a pond, and the fact that in winter the water temperature is around 39°F., ice isn’t an issue at the bottom of a pond, and the frogs and turtles that overwinter there don’t usually freeze.
However, sometimes ponds freeze over before amphibians or reptiles that overwinter in them arrive at their hibernacula. Apparently this is what happened to these Leopard Frogs, and they took refuge in the only open body of water they could find – a large but shallow puddle about 10’ wide by 20’ long in a dirt road. Shortly after they arrived temperatures dropped and the frogs were trapped under (and eventually will be encased in) the ice. Unlike Wood Frogs, Spring Peepers and Gray Treefrogs, Leopard Frogs are not freeze tolerant, so their demise is inevitable. (Thanks to Kelly Maginnis for photo, and Jim Andrews for his herpetological expertise.)
One of my very favorite animal signs is the winterized home of a Deer or White-footed Mouse. Most songbirds do not re-use their nests. Once the nestlings have fledged, what doesn’t get recycled directly from the nest by other birds or critters slowly disintegrates from rain and snow. That is, unless an agile mouse discovers it and renovates it first. Deer and White-footed Mice are known for using abandoned nests as larders (see https://naturallycuriouswithmaryholland.wordpress.com/2013/10/25/mice-preparing-for-winter/) or as homes for the winter. For the latter, a roof is constructed, usually out of milkweed or cattail fluff, but I have even found man-made insulation used as construction material for a roof. (The pictured nest has been well insulated with a roof of cattail fluff.)
There are a few weeks in September and October when acorns (and beechnuts) are mature enough to eat, but haven’t yet fallen to the ground. Porcupines take advantage of this nutritious supply of food that is not yet accessible to small rodents, deer and turkeys, and climb oak trees to consume acorns. Because an average porcupine weighs between 12 and 35 pounds, it is unable to climb all the way out to the end of a branch, where acorns are located, so it nips off the tips of fruit-bearing branches and then scoops out the acorn, leaving the cap still attached to the branch (diagnostic porcupine sign). When all the acorns on a branch have been eaten, the branch is discarded. You can often find many of these branch tips, or “nip twigs,” in the canopy of large oaks on a good mast year, but inevitably some fall to the ground. The end of the twig is usually cut at a 45° angle, and often you can see the lines made by the porcupine’s incisors. (Beechnuts are also harvested in this manner, as are the cones and terminal buds of eastern hemlock in winter.) Red squirrels also nip twigs in order to reach fruit, but typically do so when they harvest the cones and terminal buds of conifers. (Thanks to Ethel & Michael Weinberger for photo opportunity)
In the Northeast, honeybees typically choose a protected site such as a hollow tree in which to build their hive. Harsh winters demand this protection. Infrequently you will see where an attempt has been made to survive the elements without anything to contain the heat that the honeybees produce by shivering, or to block the wind, snow or sleet. Inevitably, this far north, the colony does not survive the winter.
Even though Deer Mice are active year round, we don’t often see them, as they are active from dusk until dawn. During the winter, when it’s very cold, they commonly resort to short periods of torpor (4 to 9 hours) during the day to conserve energy. While torpid, their body temperature may fall to 55° F. from a normal temperature of 98°F.
When active, Deer Mice travel both under and on top of the snow. When travelling under the snow, they tunnel through it or use tunnels created by other small mammals. When travelling on top of the snow, their tracks, and often the drag mark from their tail, are evident. The pictured Deer Mouse was found curled up, frozen, at the end of a very lengthy trail of tracks and tunnels that ran over and through woods. Where the tracks began there was a slight depression in the snow (no tunnel, no tracks), indicating that the mouse might have fallen from the air after escaping from the talons of a bird of prey.
Rabbits and hares comprise much of a Bobcat’s diet, but when prey is scarce or hard to capture, adult male or sometimes large adult female Bobcats will attack bedded, weak or injured adult White-tailed Deer. Bobcats often cache prey (such as a deer) that is too large to eat in one feeding, returning to feed on it for an extended period of time. They scrape up leaves, bark, twigs, soil. snow – whatever is available – and cover their prey. When feeding on a deer, Bobcats bite away the hair to avoid eating it, and this discarded hair is frequently mixed with the debris that the cat drags over the kill to cover it (see main photo – taken the day after the deer was cached), or is left windblown around the carcass. A characteristic sign of Bobcat feeding is the amount of hair strewn around the carcass and the lack of broken long bones (Bobcats don’t have the strength to break them with their teeth).
Typically a Bobcat rests near its cache to protect it, but it doesn’t take long for other animals to detect and take advantage of an easy meal. Within three days of this deer being cached, Coyotes and Common Ravens had discovered it, and both they and the Bobcat had eaten enough of it to expose the deer’s rib cage (see insert).
Other predators that occasionally cache and cover their kills include Mountain Lions, Black Bears and Fishers. Large caches found in the winter in the Northeast are likely to belong to a Bobcat or Fisher (Fishers typically cache and feed on deer that they find as carrion).
(Cache discovered by Lynn & Otto Wurzburg, who observed the Bobcat leaving after caching the deer; photograph by Lynn Wurzburg)