Bountiful acorn and apple crops have enabled black bears to delay denning this fall, as this recently-discovered apple-filled bear scat attests to. Denning is triggered by a seasonal shortage of food, low temperatures, and snow cover on the ground. When these conditions cause bears to den, they typically stay within their summer range boundaries. On average black bears enter their dens in November and emerge in April, but this varies considerably with crop and temperature conditions.
Denning sequence usually begins with yearlings, followed by pregnant females, then solitary females, females with cubs, adult males, and last, subadults (not sexually mature) of both sexes. Most dens are excavated below ground, and on well-drained, upland sites. Rarely are they re-used in consecutive years. Adult males are the first to emerge in the spring, followed by subadult males and females, then females accompanied by yearlings, and finally, females with cubs of the year.
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Red Foxes have a very diverse diet – birds, small mammals, snakes, frogs, eggs, insects, fish, earthworms, berries, fruit — the list is endless and this diversity is part of the reason that foxes thrive in almost any habitat. However, the fox whose tracks I was following recently passed up a meaty meal – that of a Spotted Salamander. The story the tracks tell suggests that the fox dropped the salamander after unearthing it from its hibernaculum and carrying it some distance. It’s likely that it had detected the sticky white toxic liquid that Spotted Salamanders secrete from poison glands in their skin when they are threatened. Unfortunately, detection did not occur in time to save the salamander’s life. Either its experience with the fox and/or freezing temperatures killed the salamander, preventing it from going back into hibernation. (Note red fox tracks to right of salamander.)
Although muskrats are primarily nocturnal, you occasionally see them in the daytime, especially in the spring and fall. They often reside in ponds or marshes, where they live in the pond bank or build their own house out of mud, cattails and other available plant material. Muskrats are herbivores, favoring cattail roots, arrowhead, bur reed, pickerelweed and other aquatic vegetation. The pictured muskrat is not feeding, however — more often than not muskrats eat their food where they find it, especially during the warmer months. It is doing its share of parental care — this is the time of year when the first of several litters of muskrats are born. While the mother nurses her four or so young, the father spends time gathering bedding material for his offspring. The muskrat in this photograph spent a morning cutting and gathering several mouthfuls of grasses growing by the side of the pond. When he couldn’t fit one more blade of grass in his mouth he would scurry down the bank and disappear into a burrow which most likely led to a chamber where his young are being raised. Like their beaver cousins, muskrats tend to keep a tidy house and forage for fresh bedding for their young with some regularity.
Long before the beetles and flies move in to get their share of a dead carcass many meat eaters have usually taken advantage of the easy meal. A motion camera on a dead white-tailed deer recently captured the images of 12 scavengers over a six day period. They included an opossum, several coyotes, a raccoon, red fox, striped skunk, American crow, raven, turkey vulture, red-tailed hawk and bald eagle. By the end of this time, there wasn’t much left except for bare bones, which, as winter progresses, will eventually be eaten as well. Not a shred is wasted – nature knows how to recycle and has been doing it for eons.
A white-tailed deer’s diet consists of a wide variety of herbaceous and woody plants, the ratio of one to the other being determined by the season. Fungi, fruits and herbaceous plants form much of the summer diet. Dried leaves and grasses, acorns, beechnuts and woody browse are important autumn and early winter food. After snowfall, the winter diet consists mostly of woody browse (twigs, leaves, shoots and buds) from many different trees (maples, birches and cedars among them). Come spring, deer eat buds, twigs and emerging leaves. Deer are ruminants (as are cattle, goats, sheep and moose). They have a four-chambered stomach, which is necessary in order to digest the cellulose in the vegetation they consume. Food goes first to the rumen, the first of the four chambers, which contains bacteria and other microorganisms that help digest the cellulose. Food is circulated from the rumen back to the deer’s mouth by the second chamber, or reticulum, and the deer ruminates (“chews its cud”). The third chamber, or omasum, functions as a pump, sending the food to the final chamber, the abomasum, where the digestion process is completed.
Some birds, especially those that eat seeds, buds, leaves and nuts, such as ruffed grouse, eat food very rapidly, faster than it can be passed through the digestive system. These birds usually have a pouch-like crop where food is stored to be digested later, when the birds are not out in the open, susceptible to predators. (see 10-24-12 Naturally Curious post) This rapid consumption and storage of food by grouse, often at dawn and dusk, is referred to as “budding.” Examining the contents of road-killed grouse crops is one way of learning more about this adaptive behavior. Assuming some of my readers might (?) share my curiosity about the diet of grouse, I occasionally post the contents of a grouse crop I’ve recently examined. My most recent dissection revealed that the grouse had switched from its herbaceous summer diet to its more woody winter diet — its crop contained no less than 232 male birch flower buds, or catkins. (Disclaimer: This crop was not that of the grouse that was the subject of the 11-9-12 post.)