Red Fox Vixens Preparing Dens
With their breeding season nearly at an end, red fox vixens are preparing for the arrival of a litter of pups in March or April. This involves locating and cleaning several dens, and then choosing one in which to give birth and raise young. An adult female red fox may use the same den year after year; eventually one of her daughters may take it over.
While specific den locations vary, most are on sandy hillsides, often in the woods but close to an open area, and usually there is water within 300 feet or so. A den typically has several entrances, with the main one measuring about ten inches in diameter. At this time of year (if there is snow on the ground) it is relatively easy to locate fox dens, due to soil that has been removed and scattered on the snow.
Vixens often renovate an abandoned woodchuck burrow, but occasionally den underneath an outbuilding, in a hollow log, rock pile or other sheltered area. Pictured are a typical hillside den as well as an abandoned beaver lodge that has been renovated by a fox. Scat (located about 2 o’clock in the photo) deposited near the entrance of the lodge indicates that this may well be a den that will be used for raising young.
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More Buds
The previous “bud scale” post engaged readers to an extent that made me feel another post with additional buds to scrutinize would be welcome. Apologies to non-woody plant aficionados!
When identifying woody plants in winter, one takes advantage of everything a tree or shrub has to tell you: bud/branch arrangement (opposite/alternate), bark, silhouette and terminal buds. Buds are so revealing that they alone can immediately tell you what species you are seeking to identify. Is there one bud at the tip of each branch (willows) or multiple terminal buds (red oak)? Are there bud scales (no-witch hazel; yes- bigtooth aspen)? If so, what are their number (willows – one) and arrangement (overlapping, like shingles – red oak)? Are the buds red (striped maple), brown (witch hazel), yellow (bitternut hickory), green, or some combination of these colors? Are they pointed (bigtooth aspen) or rounded (willow)? Every species of tree has buds with a unique combination of these characteristics. Now is the time to observe them, as some will soon start to open.
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Meadow Voles Soon To Begin Breeding
Under perfect conditions, with no predators, no deaths and abundant food, a pair of meadow voles (Microtus pennsylvanicus) could produce a million descendants in a single year. Because they are prey for nearly every meat-eating animal that exists, however, their population, while large, is nowhere near this.
Even though the number of meadow voles is relatively high and they are active day and night, year round, it is unusual to actually set eyes on one. What we do find, especially this time of year, are meadow vole signs in the snow: mazes of runways on the surface of the ground that are exposed as snow starts to melt, air-exchange holes originating in their tunnels and extending to the surface of the snow, tracks and entrance/exit holes to their tunnels.
The social behavior of meadow voles is about to undergo a seasonal change. During the winter, when they are not breeding, meadow voles are more social and commonly share their nests, probably to conserve heat. In another month, however, as breeding begins, females become fiercely territorial towards other females, and males are aggressively establishing dominance over each other. The peaceable subnivean meadow vole kingdom is about to come to an end. (Thanks to Susan and Dean Greenberg for photo op.)
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Tufted Titmice Singing
“Peter – Peter – Peter.” “Peter – Peter – Peter.” The song of the tufted titmouse is one of the first bird songs heard in late winter. Unlike its scratchy, nasal call note, the titmouse’s song is a relatively loud, clear, two-note whistle which is repeated rapidly up to 11 times in succession. If you become aware of it, it can even become a bit monotonous. While it is mostly males that do the singing, females sometimes give voice to a softer version of this song.
To hear a tufted titmouse’s song and call notes, go to http://www.langelliott.com/wp-content/mary-holland/tufted_titmouse.mp3. (Sound recording © Lang Elliott – langelliott.com & miracleofnature.org)
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North American River Otters Running & Gliding
One hundred years ago, naturalists were puzzled by the disappearance of otters in the winter. Some people theorized that they must be hibernating, but in fact, otters are active throughout the year — they just aren’t observed as often in the winter as in the summer. Because they inhabit water, where the fish that they eat are found, and often reside in bank dens (above water level), otters can spend most of their winter under cover of ice. However, some do travel over land from open water to open water, upon occasion. In fact, it is not unusual for them to cover several miles in their search for an open stream or a spring. Run and glide, run and glide, often along a frozen river or marsh, but also through the woods, where otter tracks seem so incongruous. Paired foot prints stop and start each slide; this combination is a dead giveaway as to who is making grooves in the snow. Ultimately, if you persevere when following them, you will find that these slides disappear into open water.
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Stoneflies Drumming
Stoneflies spend the larval stage of their life in streams. When the larvae mature, they crawl out of the streams they grew up in, split their larval skins and emerge as winged adults, ready to mate. Stoneflies are unique among aquatic insects in that there are different species that emerge in all months of the year. Most species mature in warmer months, but some do so during warm spells in winter and there are two families (referred to as winter stoneflies) that emerge only at this time of year, perhaps because of the scarcity of predators.
Recently, perhaps due to the warm weather this past weekend, large numbers of stoneflies emerged. In places, the snowy banks of open streams were littered with half-inch adult stoneflies whose new skins were drying. This entomological exodus from the water typically takes place at night, to avoid being eaten by terrestrial insectivores and birds. After their adult skin dries, winter stoneflies can be seen crawling on top of the snow as they search for a mate.
In many species, male and females locate each other by tapping the tip of their abdomen upon the substrate, a process referred to as “drumming.” Any stoneflies in contact with that substrate will feel the vibrations of this drumming. Male and female drumming patterns are specific for each species and for each sex. Male stoneflies initiate drumming and females answer. This means of auditory communication is closely related to the “songs” of crickets, grasshoppers and katydids. The difference is that the sound waves of the terrestrial insect songs travel through the air and are loud enough for humans to hear, whereas the sound waves of stonefly drumming travels through a solid medium and is inaudible to us.
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Coyotes & Moles
Foxes and coyotes are very apt to dig into the ground where they detect the presence of a mole. In the pictured scene, the digging of a coyote was evident from the disturbed snow and earth and the abundance of coyote tracks. Two excavated holes led directly into an underground tunnel.
While many sources state that moles are part of a coyote’s diet, there are many instances, including the one pictured, where the mole (hairy-tailed) is left untouched after being unearthed by a coyote. Unlike northern short-tailed shrews, moles are not toxic and one wonders what occasionally prevents a coyote from consuming its prey.
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Scent Posts
Scent posts can serve as territorial markers as well as a means of conveying hierarchy, breeding status, gender, fitness, etc. When you think of a scent post, where an animal deposits its scent either by rubbing, urinating or defecating, one often thinks of it as being used by one animal to communicate with other individuals of the same species. However, for whatever the reason, a rock, stump or the junction of two trails can prove irresistibly appealing to more than one species. Each chooses to leave messages for other members of its respective species at the same location. In this case, two predators, a Fisher (left) and an Eastern Coyote (right), left their scat at the base of a rotting stump. The tracks of both of these animals were evident throughout the area. In sharing the same scent post, were they vying for the same territory, advertising for a mate (both are at the peak of their mating season), or simply making their presence known? Unfortunately, the human nose isn’t equipped to answer this question.
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Beaked Hazel
Because of the popularity of hazel nuts, it is surprising to find viable fruits on Beaked Hazel (Corylus cornuta) in mid- to late winter. Ruffed Grouse, Wild Turkey, Red-bellied Woodpeckers, Beavers, Snowshoe Hares, Raccoons, Red Squirrels, Eastern Chipmunks and White-footed Mice all vie for these delectable nuts.
This multi-stemmed, wind-pollinated shrub bears fruit that is wrapped in a modified leaf (involucre). Beaked Hazel (as opposed to American Hazel, Corylus americana) is named after the tapering beak-shape of its nuts’ involucres. One might suspect that any fruits remaining on hazel shrubs at this time of year must not be edible, but the photographed specimen was very tasty!
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Porcupine Preyed Upon By Coyotes
Coyote tracks from several directions coalesced in a spot where the frozen skin of a porcupine lay. There was not one morsel of flesh, and next to no bone, left inside the skin, which had partially been turned inside out. Inspection of the porcupine’s head confirmed the likelihood that coyotes were responsible, as fishers, notable porcupine predators, kill their prey by repeatedly attacking a porcupine’s head, and the head of this porcupine was unscathed (see insert). The only other possible predators would be a bobcat or a great horned owl, and there were no signs of either present. While it is possible that the porcupine died a natural death and opportunistic coyotes took advantage of an easy meal, it appeared to be in good condition, and thus it is equally or more likely that coyotes succeeded in gaining access to the porcupine’s vulnerable, quill-less belly, and successfully attacked and ate it.
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Birds & Burdock
The phenomenon of North American birds being killed by becoming entangled in Common Burdock (Arctium minus) has been documented since at least 1909, when one observer (in A.C. Bent’s compilation) described finding a multitude of Golden-crowned Kinglets in Common Burdock’s grasp:
They were visible in all directions, scores of them sticking to the tops of the clumps on the most exposed clusters of heads. The struggle had ended fatally for all that I saw, and its severity was evidenced by the attitudes of their bodies and the disheveled condition of their plumage. I examined a number of the burdock heads to determine that attraction had brought the kinglets within range of the hooks, and found insect larvae of two species present in considerable abundance.
Typically this phenomenon involves birds that are seeking either insects that are inhabiting the seed heads, or burdock seeds. The birds’ feathers get caught by the hooked bracts (modified leaves) that surround both the flower heads and seed heads of burdock. Small birds such as kinglets, gnatcatchers, goldfinches, nuthatches, hummingbirds, chickadees, warblers and siskins are the usual victims, but larger birds, including a Blue-headed Vireo and a Barn Swallow, have been caught as well. Most of these birds were found with their wings and tail spread, and caught by many parts of their bodies. The more they struggled, the more their feathers became entangled. Victims are not limited to birds — in 1925, a dead bat was discovered caught in a patch of burdock. (Photo by and thanks to Holly Brough)
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Black Bear Lactation Typo
Correction: A Black Bear cub weighs roughly 8 OUNCES, not POUNDS, at birth!
Black Bear Lactation
Black Bear cubs are born in late January or February, weighing about eight ounces. The newborn cub(s) immediately crawl to their mother’s teats (she has six) closest to her pelvis to nurse. Later, as the cubs get older, they nurse from the top four and the mother often “switches off” production in the bottom two. At birth a Black Bear cub weighs half to three-quarters of a pound, and when it emerges from the den in April it averages about six pounds.
Most hibernating mammals are not pregnant. The fact that Black Bear cubs are born in late January or February, and the mother bear nurses them for two or three months while she is not eating or drinking is a phenomenon in and of itself – just ask any ravenous nursing human mother.
Milk production and intake increases four-fold after the cubs emerge from the den. At peak lactation (June and July) a black bear cub consumes about 30 ounces of milk a day. If a bear has two or three cubs, that means she must produce two or three quarts of milk a day. The milk of Black Bears is very rich: human (and cow) milk is about three to five percent fat while Black Bear milk is around 20 to 25 percent fat. In addition, the carbohydrate composition of the Black Bear mother’s milk while she is nursing in the den is relatively high compared to the carbohydrate composition found in milk after denning; the protein content after denning is double that of milk produced during hibernation. At roughly six to eight months of age, Black Bear cubs are weaned. (Thanks to Ben Kilham for photo op.)
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Cedar Waxwings Seeking Fruit
Cedar Waxwings can be found year round in northern New England, but the waxwings we see this winter are not necessarily the same birds that were nesting here last summer. May through September Cedar Waxwings can be found nesting throughout New England. Come fall, most Cedar Waxwings migrate an average of 880 miles in a southerly direction. Thus, many of the waxwings we see in winter are probably Canadian breeders.
Once on their wintering grounds, Cedar Waxwings tend to wander in flocks in search of sugary fruits to eat. In recent years, they have relied increasingly on crops of ornamental fruit trees such as crabapple, hawthorn and mountain ash. In the summer, you see Cedar Waxwings regularly if they are nesting in your area, whereas if you see them one winter day, you may very well not see them the following day, unless there is an ample supply of fruit nearby. Once they discover a food source, be it fruit on a single tree or an orchard full of fruit, these nomads usually descend, strip and eat the fruit until the branches are bare and then depart for greener (or redder) pastures.
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Red Foxes Scent Marking & Breeding
Red foxes communicate in a number of ways, one of which is to scent mark with urine. During their breeding season, which is at its peak this month, male fox urine takes on a strong skunk-like odor, detectable by most human noses. These “sign posts” advertise the fox’s presence, its dominance and sexual status to all other red foxes that pass by.
Foxes leave scent marks along the boundary of their territory, as well as within it. Often you will find both urine and scat placed strategically on elevated objects, such as rocks, stumps and vegetation emerging from snow as well as at the intersection of two trails. Both male and female foxes leave scent marks. Researchers have found that when foxes are looking for food, they mark up to 70 times an hour. When just traveling and not hunting, they do not mark as frequently.
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Red-eyed Vireo Nests
The Red-eyed Vireo’s nest is indisputably a work of art. Unlike most songbird nests, it is suspended below the branch to which it is attached. Perhaps the observant eye of Arthur C. Bent, a compiler of firsthand bird observations in the early to mid-1900’s, describes it best.
“The red-eyed vireo builds a dainty little pensile nest suspended usually from a forking, horizontal branch of a tree, rather below the level of our eyes as we walk through second-growth. The nest is a beautifully finished piece of workmanship, constructed of fine grasses and rootlets, bits of birch bark, and paper from wasps’ nests, bound together and to the supporting branches with spider’s or caterpillar’s webbing, and , perhaps the most constant material, long, narrow, flexible strands of grapevine bark, which help to hold up the cup of the nest. “
As mentioned, pieces of Bald-faced Hornet nests are frequently incorporated into the outside of a Red-eyed Vireo’s nest. These papery bits of hornet nest are purely decorative, and serve no structural purpose. Hornets are aggressive and defend their nests vigorously, so much so that it is unusual to find birds nesting in close proximity to a hornet nest. A vireo nest covered with papery bits of a hornet’s nest looks very much like a young hornet nest. It is conceivable that the use of this decorative material is a strategy employed by vireos to ward off potential nest predators.
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Bud Scales
Much of this coming summer’s woody plant growth is contained in embryonic form inside a tree’s buds. Buds contain an undeveloped shoot, leaf, and/or flower. Formed last summer, these buds must survive the freezing and fluctuating temperatures, relatively dry air and the potential insect, bird and fungal damage that may occur during the fall, winter and early spring.
Bud scales, which are small, modified leaves, cover and protect many of these buds. The number of scales, their arrangement, color, presence or absence of hairs or sticky substances are often distinctive. Willows have one visible bud scale (actually two fused into one), whereas pine and fir buds may have anywhere from 100 to 350. The scales on a bud can either be arranged in pairs facing each other edgewise (American Basswood, pictured) or overlapping like shingles (Sugar Maple, pictured). Colors range from the wine-colored bud scales of Striped Maple to the mustard yellow Bitternut Hickory scales. The texture of bud scales has great variation, including the satiny-smooth hairy bud scales of Box Elder (pictured). Many bud scales, such as poplars, are covered by a gummy substance which serves as added protection.
A few trees and shrubs have buds that lack scales. These are referred to as “naked” buds, and often the embryonic leaves are quite hairy. Witch Hazel, Hobblebush and Staghorn Sumac (pictured) are species of woody plants lacking bud scales.
Most buds have multiple scales which, upon falling off when the bud opens, leave a series of horizontally-elongated scars on the surface of the growing stem. By means of these scars one can determine the age of a young branch, since each year’s growth ends in the formation of a terminal bud which produces an additional group of bud scale scars. Continued growth of the branch causes these scars to be indistinguishable after a few years so that the age of older branches cannot be determined by this means.
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Porcupine Tracks
Alas, yesterday’s Mystery Photo ‘twas not made by a squirrel loaded down with a bag of nuts, a guess hazarded by one reader, but, as most of you knew, it was created by a Porcupine, or Quill Pig (Erethizon dorsatum). A bit pigeon-toed, Porcupines walk with their feet pointed slightly inward, with their feet flat on the ground. Their pebbly soles rarely leave a distinctive pattern, and their toe pads are not usually evident, but under the right conditions, their nails do make an impression. Usually a Porcupine’s quill-laden tail is raised slightly as it moves, but occasionally it drags along the surface of the snow as the Porcupine walks, producing a broad band composed of very fine lines that weaves between the Porcupine’s tracks, as in yesterday’s photo.
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Mystery Photo
Who made these tracks? Hint: Just as one sometimes reads between the lines to understand the real message that is being relayed, it can be helpful to observe the space in between tracks for additional information. (Please post answers under “Comments.”)
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American Martens in Northern New England
American Martens (formerly Pine Martens) are making a comeback in northern New England. On New Hampshire’s Threatened Species List, and on Vermont’s Endangered Species List, American Martens are rebounding from the effects of habitat loss and trapping in the early 1900’s, but are still considered rare. This medium-sized member of the weasel family is slightly larger than a Mink and smaller than a Fisher, and often has a light orange bib, or throat/chest patch. Lighter fur usually is found on their head and along the edges of their ears. In addition to a pair of scent glands, which all weasels have, American Martens have a glandular area on their lower abdomen that exudes a musky-smelling, oily secretion used for scent marking.
American Martens spend a lot of time in trees. Their semi-retractable claws help them climb and hang onto branches. In addition, their hind limbs can be rotated at the ankle (like Gray Squirrels) to allow them to descend a tree very quickly, and their long, bushy tail helps them balance.
Because they store very little fat, martens must hunt every day. In the winter they are active for about four hours a day (14 hours/day in the summer), and during this time consume an average of three voles or the equivalent amount of chipmunks, birds or other small rodents. A sighting of an American Marten is a highly-prized experience. (Thanks to Laurie Stokes, whose photo of a Pine Marten was taken in the White Mountains of New Hampshire.)
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Ruffed Grouse Unable To Seek Refuge in Snow Caves
Unlike much of the Northeast, central Vermont has only a few inches of snow on the ground. These conditions can affect all forms of predators and prey both negatively and positively, from exposed mice and voles to easily-satiated hawks and owls. In the case of Ruffed Grouse, which seek shelter on cold winter nights by diving into the snow, less than 10 inches of snow can spell disaster. In their snow caves they are hidden from view and well insulated (where it rarely drops below 20°F.). A lack of snow can be life-threatening for grouse if the temperature drops too low for too long. Unable to create a sheltered cavity in the snow, Ruffed Grouse bed down on top of it, often close to the base of a tree where there may be some shelter from the wind. Fortunately, most nights have not been extremely cold thus far this winter.
After the grouse departs in the morning, you often find scat where it bedded down. Grouse scat comes in two forms, one a dry, fibrous cylindrical pellet with a white-wash of uric acid at one end, and the other a softer, darker brown plop. The vast majority of a grouse’s diet (buds, twigs, leaves, catkins) goes directly through its digestive system and forms the dry, courser scat. Finer (and more nutritious) material such as the cambium layer of woody plants enters the caeca, two specialized pouches, before passing through the large intestine. The caeca contain bacteria which break down cellulose and produce the more digested, and therefore more liquefied, scat (see foreground in photo).
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