The signs of fall are plentiful – skeins of migrating geese, disappearing insects, falling leaves. Another transformation that takes place in the fall (as well as spring) with White-tailed Deer and other mammals is the molting of a summer coat and the growing in of a winter coat.
The thinner summer coat of a White-tailed Deer consists of shorter, reddish hair. The shorter length of the hair allows the deer’s body heat to easily escape and the light color reflects rather than retains warmth from the sun. Come fall, deer molt the rusty red hairs of summer, and replace them with a coat consisting of longer, darker hairs. This grayish-brown hair is warmer and absorbs more of the sun’s warmth. A spring molt occurs in reverse.
The process of molting happens relatively fast and is often completed within two to three weeks. During this period, deer can look a bit ragged (see photo), as both the red summer hairs as well as the brown winter hairs are evident. If you see a deer at this time, it’s easy to assume that such a deer has mange, but it is just the way a seasonal molt takes place. (Photo by Erin Donahue)
Male White-tailed Deer grow a new pair of antlers every year starting when they are one year old. The size of the antlers depends on the age of the deer, genetics, and diet. Before antlers actually appear, structures called pedicles that connect the antlers to the skull develop. Growth of the actual antlers begins in March or April and as more nutritious food becomes more available during May and June antlers grow more rapidly.
Antlers are one of the fastest growing bones that exist; growth is regulated by hormones which are controlled by the photoperiod, or length of day . Yearling antlers can grow about 1/8-inch a day during the summer, and adults as much as 1/4th of an inch. While they are growing, antlers are covered with a layer of tissue called “velvet” which is dense with blood vessels that carry nutrients to the antlers. In August the supply of blood to the velvet diminishes and the antlers begin to harden. By September the velvet has dried and is falling off. Antlers are used as weapons during rut, or the mating season, after which they fall to the ground, providing a valuable source of calcium and phosphorus for rodents. (Photo by Erin Donahue)
White-tailed Deer bucks grow and shed a pair of antlers annually. The main purpose of these bony growths is to serve as weapons against rival bucks during rut, or mating season. During this time in the fall, prior to their 24-hour receptive period, does release chemicals to signal their readiness to bucks. These chemicals keep the bucks’ testosterone level high, which in turn keeps antlers firmly attached to their heads. Once rut is over, does stop emitting these chemicals, and as a consequence, the bucks’ testosterone level drops significantly.
When a buck’s testosterone level drops, it triggers cells called osteoclasts to become more active in the buck’s pedicles, the permanent bony bases which anchor the antlers to the buck’s skull. As a result, calcium is extracted from the pedicles which weakens the antlers’ connection to the buck’s skull, and eventually the antlers drop off.
It is rare that both antlers drop at the same time – usually there are four to eight days between the loss of the first and the second antler. I assumed that bucks needed to knock their antlers against something hard, such as the trunk of a tree, in order to get them to fall off. However, years ago I witnessed a buck shedding an antler simply by dropping his head and then quickly flicking it upwards, sending an antler flying through the air. (Note pedicle where antler used to be attached. Photo by Alfred Balch)
Coyote tracks from three different directions led to an area where a deer’s well-cleaned skull was the only remnant of a communal meal. It had been dug up from a spot nearby where it had been cached, and carried to a more protected area to work on. Coyotes are omnivores, but about 90% of their diet consists of mammals. Coyote scat I’ve examined has included, among other things, the hair of Muskrat, Snowshoe Hare, White-tailed Deer and small rodents as well as feathers, grass and apples.
Coyotes are commonly blamed whenever there is a decline in the White-tailed Deer population. Studies involving the removal of deer populations in a given area have not found any evidence that Coyote removal caused an increase in the deer population, nor did it affect the overall deer population growth. The fact that Coyotes are not causing deer populations to decline can also be seen in the devastating effect White-tailed Deer are having on forest ecosystems throughout the eastern United States as the Coyote population increases.
That’s not to say Coyotes don’t hunt deer – they do, primarily in the spring (fawns) and in the winter, especially when there is enough snow and/or crust to slow deer down but not Coyotes. However, much of their venison consumption is a result of their scavenging deer carcasses, which they do any time of year. Examine Coyote scat and the chances are great you will find deer hair in it; chances are also great that it came from a carcass, not a living deer.
Bobcats are active all winter, particularly at dawn and dusk, when their primary prey (hares and cottontails) are active. Mice and voles are also a significant part of their diet, and occasionally larger-bodied male Bobcats successfully prey on White-tailed Deer. The pictured tracks reveal that while foraging for food, a Bobcat discovered the remains of a Porcupine that had been killed and skinned by a Fisher.
White-tailed Deer are ruminants. The process of rumination (gathering a lot of food at once and then digesting it later by chewing one’s cud) is fully developed by the age of about two months, or roughly by the end of July. Fawns can be completely weaned and survive without milk at this time, but does often don’t wean them until 3 to 4 months. It’s not unheard of to see a fawn born in May or June still nursing, or attempting to, in October. It stands to reason that it’s hard to give up this valuable source of nutrition, for deer milk is richer in fat, protein and energy than cow’s milk. (Photo taken by Erin Donahue on September 2nd.)
The pollinated and fertilized white flowers of Red Elderberry (Sambucus racemosa) have recently developed into the red fruit for which this plant is named. Many people are familiar with its relative, Common Elderberry (S. canadensis), which produces dark purple fruit that is used to make jams, jellies, pies and elderberry wine. While Red Elderberry fruit can be used to make all of these, its raw berries are toxic. Red Elderberry’s popularity is greatest with pollinators, birds and four-footed mammals.
The cyanide-producing toxins in its flowers, (raw) fruit, stems, bark, leaves and roots do not seem to discourage wildlife’s attraction to Red Elderberry. The odor of its flowers, its nectar, and its highly nutritious pollen attract many ants, bees, wasps and flies. At least 50 species of songbirds eat the bright red fruits, including red-eyed vireos, ruffed grouse, song sparrows, gray catbirds, brown thrashers, and thrushes. Squirrels, mice, raccoons, and black bears also eat the fruit. Porcupines, mice and snowshoe hares eat the buds and bark in winter. The foliage is usually avoided by herbivores, although white-tailed deer and moose browse on it occasionally.
Cattails, sedges, rushes, water lilies and grasses make up the bulk of a Muskrat’s diet although these aquatic rodents have been known to occasionally dine on fish, crustaceans and freshwater clams.
Muskrats typically don’t eat their food where they find it – they usually bring it out to a feeding platform in the water, which provides them with some protection from predators. However, they make an exception for Bullhead Pond-lily flower buds (Nuphar variegata), also known as Spatterdock, which they often devour on the spot wherever they find them (see photo). Beavers, Porcupines (yes, Porcupines can swim), White-tailed Deer and waterfowl also dine on the leaves, rhizomes, buds, flowers and seeds of Bullhead Pond-lilies.
When your quest is to find out as much as you can about the identity, activity, diet and territory of your four-footed neighbors, it is logical to make the most of all your senses. Tracks can be seen, scrapings and bite marks on a tree can be felt and yes, one’s sense of smell can enhance any tracking expedition. Just as the tracks and scat of different species of animals have distinctive characteristics, so does the urine of different animals. Scent marking, including urination, is a behaviour used by animals to identify their territory, and therefore a highly visible sign in winter.
At this time of year, foxes are breeding, and without even putting your nose near where a fox has marked his territory with urine, you can detect its skunk-like odor as you pass by. If you’re so inclined (and I realize many readers may not be) you can heighten your sensory experience as well as your identification prowess by sampling the smell of other animals’ liquid waste. White-tailed deer urine has a pungent, piney smell, quite pleasing to this naturalist’s olfactory receptors. You can detect a porcupine den from a considerable distance by the pungent, very distinctive but hard to describe odor of its urine (which spills out onto and coats the bark of a tree den, thereby advertising the porcupine’s presence). Coyote urine smells very much like a domestic dog’s, and members of the weasel family often have musky-smelling urine, though a recently-sniffed fisher marking had very little scent.
Needless to say, it’s a lot easier to discover and sample urine when there’s snow on the ground and it is more evident. Virginia opossums, snowshoe hares, red and gray squirrels, eastern coyotes, red and gray foxes, raccoons, fishers, mink and striped skunks are all in or entering their breeding seasons, when scent marking is more frequent. Snow is currently on the ground, at least in northern New England. It’s prime time for olfactory activity, if you’re game. (Photo: stump marked by a red fox)
Coyotes are considered opportunisitic omnivores and will eat just about anything. As the seasons and the availability of foods change, so does the coyote’s diet. During the summer, coyotes feed upon berries and insects. Small mammals are an important prey of choice during the fall and into the winter. As winter becomes harder and small mammal populations decline, coyotes turn toward their largest prey – white-tailed deer.
It is not uncommon to come upon deer carcasses in the winter which have been cleaned within an inch of their life by coyotes, illustrating their preference for this ungulate. However, the majority of deer carcasses consumed by coyotes are not killed by them, but are discovered as carrion or road kills. Coyotes infrequently kill healthy adult deer. Occasionally, working in packs, they will chase them down. Scat dissection shows that in late spring, coyotes prey on fawns.
A study of coyote predatory behavior in New York state several years ago found that during the winter, only 8% of adult deer carcasses visited by coyotes had been killed conclusively by coyotes. The remaining 92% were scavenged by coyotes after being killed by vehicles and other injuries. The adult deer that were killed by coyotes had severe pre-existing injuries and were likely to die from other causes in the absence of coyote predation.
Ruffed grouse, white-tailed deer and moose, all prey species and all plant eaters, share certain characteristics that have to do with food consumption and digestion. They all tend to eat large quantities rather quickly in one spot, and then move to another, safer, spot to digest their food. This technique minimizes the amount of time that they are likely to be out in the open and focused more on eating than on predators. Eating quickly and storing the consumed food in a chamber and digesting it later at their leisure, under cover, makes a lot of sense.
All three animals have a multi-chambered stomach and microorganisms efficient at breaking down cellulose and extracting nutrients from plants. After browsing on branches and buds, deer and moose seek shelter where they then regurgitate and chew their cud. Grouse do not linger over their meals – 20 minutes of foraging will sustain them all day. Leaves, buds and twigs are stored in their crop (a wide portion of the esophagus) until the grouse seeks shelter, where the food eventually reaches their gizzard. Here, with the aid of gravel, it is ground up.
While the flowers of Red (Actaea rubra) and White Baneberry (Actaea pachypoda) are quite similar (the flower head of Red Baneberry is more globular than the elongated head of White Baneberry), their respective fruits, the color of which gave them their common names, quickly distinguish these two species from each other.
White Baneberry produces white fruits commonly called “Doll’s eyes” due to the persistent remains of the flower’s stigma, which leaves a black dot on each fruit. Red Baneberry’s shiny red berries also have these black dots, though they are not as apparent. All parts of both species are poisonous, with the berries being the most toxic part of the plant.
Seed dispersal is carried out by animals that have enough tolerance to feed on the berries. These animals include various mice, squirrels, chipmunks and voles, as well as a wide variety of birds and White-tailed Deer.
Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
White-tailed does give birth at the end of May and the beginning of June. A doe giving birth for the first time usually has one fawn; in subsequent years, two or three fawns are common. For the first three or four days after it is born, a fawn is odorless and is well camouflaged thanks to its spotted coat.
During this time the mother leaves her offspring (who remain motionless during her absence) and goes off to feed. (It can be three weeks or so before the fawns follow their mother when she feeds.) The doe stays away as much as possible from her fawns during these first days and weeks to prevent her own body scent from giving away their location. She returns to nurse her young eight to ten times in a twenty-four-hour period.
People discovering what looks to them like an abandoned fawn should know that although the doe may not be in sight, she most likely is within hearing distance and is probably watching them. The fawn has not been abandoned and should not be disturbed. (Thanks to Erin Donahue, who took this photograph.)
Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Microorganisms inside a deer’s four-chambered stomach enable cellulose in the plant material consumed to be digested. In winter, the microorganisms within the deer stomach are different from the microorganisms in spring, summer, and fall. This change allows deer to digest a diet of woody browse during winter months and turn the high-fiber diet into proteins through intricate physiological processes. Among their preferred browse are White Cedar, Yew, American Basswood, Alternate-leaved and Flowering Dogwood, Maples, Staghorn Sumac and Witch Hobble.
Offering food items during this period other than woody browse (such as hay) is detrimental to deer, as it requires different microorganisms in the stomach in order to be digested. Thus, even though a deer’s stomach might be full (of hay, for instance), it may starve due to the inability to digest it. (Photo: White-tailed Deer browsing on Eastern Hemlock)
Scent-marking plays an important communication role in the animal world. A variety of species use glandular secretions to convey (for some distance) messages. From beavers spreading castoreum on scent mounds to fishers leaving their scent every time their hind feet touch the ground, the woods are alive with messages often undetected by most humans. Some of these are left by White-tailed Deer, which have two primary scent-marking behaviors: antler rubbing and scrapes.
One used to associate an antler rub with the act of a buck removing drying velvet from its antlers. However, it turns out that very few rubs are made by deer removing antler velvet, a process that’s normally completed within 24 hours. Instead, most rubs are made by relatively few dominant bucks to signal their readiness to breed and to mark their territory.
All White-tailed Deer possess specialized forehead glands that become increasingly active in autumn, particularly in adult males. All bucks spread their scent by rubbing their foreheads (which contain specialized scent glands) against trees and shrubs that have smooth bark, few, if any, lower limbs and are ½” to 4” in diameter. (Older bucks also will rub trees six or more inches in diameter.) In the Northeast, Trembling Aspen, Staghorn Sumac, Red Maple, and willows are often used for this purpose.
Mature, socially high-ranking bucks exude greater amounts of the glandular secretion than do younger males or females. They begin marking their territory soon after losing velvet and continue marking until they cast their antlers in December or January. The chemical signals left at a rub site tend to suppress the aggressiveness and sex drive of young males. However, those same signals stimulate females. The amount of rubbing an individual buck does depends on the level of testosterone in his blood, which in turn is largely determined by the animal’s age and dominance status.
We may not be able to detect the chemicals on a rub, but it’s hard to miss the sight of the light-colored blazes that magically appear in the woods at this time of year. (Photo: White-tailed Deer rub on Staghorn Sumac. Thanks to Chiho Kaneko and Jeffrey Hamelman for photo op.)
By the end of August, White-tailed Deer fawns are about three months old. Their mother weans them between two and four months of age and during this time they molt, losing their white spots. A new gray-brown winter coat replaces the coat they were born with.
Such creative and informed answers to yesterday’s Mystery Photo, and many that were right on the mark! To set the stage, several 2” to 4”-deep holes riddled the ground under a stand of Eastern Hemlocks. Something had obviously been digging for something, but who and what? Close inspection of the holes revealed two things. The animal that had dug the holes had run into some thick hemlock roots, and with a clean 45° angle cut, had snipped them in order to have access to the soil beneath them. Secondly, some of the holes had pea- to marble-size, spherical tan objects that resembled puffballs both lying at the bottom and wedged into the sides of the holes.
Only because I had read Paul Rezendes’s Tracking & the Art of Seeing years ago did I recognize these holes and spherical structures within as the work of an animal looking for false truffles (a genus of fungi) to eat. By putting the various clues together – a hemlock stand, 3” to 6”-wide holes, clean incisor-snipped roots, and a few remnant truffles – the mystery at to what was being sought was solved.
As to who had done the digging, white-tailed deer, squirrels and porcupines all fancy false truffles. Both porcupines and squirrels have incisors that would make a clean cut through the roots. If porcupines had been digging here, there would likely be scat and/or quills lying about, which there were not. Thus, most likely it was a squirrel that had smelled, unearthed and eaten the false truffles.
Rezendes found that the truffles he discovered had dried spores inside them, and assumed that this made them undesirable to the animal that unearthed them and therefore they were not eaten. The spores of the truffles I found were not dried out, so I have no idea why they weren’t eaten, but I’m very glad they weren’t, as their presence allowed me to solve this mystery and see this phenomenon which I’ve been looking for for decades.
It may interest some to know that false truffles and Eastern Hemlocks have a symbiotic relationship. The fungi are attached to hemlock roots, so the minerals and water they absorb are available to the hemlocks. The hemlocks provide the fungi with sugars that they (hemlocks) produce through photosynthesis. Squirrels (and porcupines and white-tailed deer) and eastern hemlocks have a similar mutually beneficial relationship in that hemlocks provide the truffle-eaters with food, and the squirrels, porcupines and white-tailed deer disperse the spores of the truffles they’ve eaten. (Caution: Do not eat false truffles – they are considered toxic to humans.)
Coyotes will eat just about anything they come across – rodents, rabbits and hares, beavers, muskrats, birds, even garbage. Whatever is available and whatever they can catch they will consume. Very often you find white-tailed deer hair in their scat (see photo), and while a majority of the time it comes from deer carcasses that they have come across, there are two times of year when they are known to hunt deer. One is in the spring, when fawns are vulnerable, and the other is during the winter, when one of two conditions are present that favor coyotes: when the snow is deep and deer have to struggle to move faster than coyotes, and when there are crusty conditions, when coyotes are held up on top of the crust, but deer break through, often cutting and exhausting themselves.
Many wild animals are nocturnal or crepuscular, limiting our chances of firsthand observation of them. Those of us curious to learn more about their lives take advantage of whatever signs these elusive animals leave. In winter, evidence of their presence in the form of tracks and scat can tell us not only their identity, but their diet, direction of travel, size, etc. Beds, kill sites and signs of feeding also provide crucial information. There is one more sign that is often overlooked and under-utilized for identification purposes, and that is the scent of an animal’s urine.
Not everyone will necessarily wish to add this identification tool to their arsenal of naturally curious skills, but for those willing, scent-detection can be extremely useful, especially if conditions for tracking are poor, or if scat is not found. Not only is the scent of a species’ urine distinctive, it can often be detected at a distance. At this time of year (breeding season) red fox urine can easily be mistaken for striped skunk spray. Porcupine urine is strong and distinctive, but hard to describe. Once you’re familiar with it, it can guide you to the location of a den. Coyote urine is very dog-like; bobcat very cat-like. Surprisingly agreeable is the pine-like scent of White-tailed Deer urine (pictured).
Antlers, the fastest growing mammal tissue on earth, are grown by male White-tailed Deer (and very occasionally females) every year and shed every year. They begin growing in the spring, usually April, and complete their growth in August or September. During this period they are covered with “velvet,” a soft skin containing blood vessels and nervous tissue that supply oxygen and nutrients to the antler. Once growth ceases, the velvet dries up and falls off or is inadvertently rubbed off. The mating season of White-tailed Deer, or rut, during which time their antlers are instrumental in establishing hierarchy and securing a mate, peaks in mid-November. Once mating is over, the disadvantages of antlers (cumbersome shape for traveling through woods, and the energy required to carry them) promote the shedding of these bony structures. Specialized cells (osteoclasts) destroy the bone tissue between the antlers and the skull and antlers are shed sometime between the end of December and the beginning of February.
Most sources state that antlers just fall off or that the buck knocks them off by striking them against a tree. My personal observation of a buck in captivity clarified the way antlers are dropped, at least in this one instance. The buck put his head down, quickly jerked it up and to one side, and the antler went flying.
The diet of White-tailed Deer varies with the seasons, but in general deer require a high-quality diet and tend to choose the most nutritious options available. In addition to mast (fruit, acorns, beechnuts) and browse, herbaceous plants and fungi make up the greatest portion of their food. However, their foraging choices are extensive. White-tailed Deer have been known to consume the washed-up carcasses of alewives after they (the alewives) have spawned as well as insects, mice and the nestlings of ground-nesting songbirds.
Microorganisms inside a deer’s four-chambered stomach enable cellulose in the plant material consumed to be digested. In winter, the microorganisms within the deer stomach are different from the microorganisms in spring, summer, and fall. This change allows deer to digest a diet of woody browse during winter months and turn the high-fiber diet into proteins through intricate physiological processes. Offering food items during this period other than woody browse (such as hay) is detrimental to deer, as it requires different microorganisms in the stomach in order to be digested. Thus, even though a deer’s stomach might be full (of hay, for instance), it may starve due to the inability to digest it. (Photo: shelf fungus eaten by White-tailed Deer, showing lower jaw incisor grooves)
Even if you didn’t know that a white-tailed deer’s diet changes in the fall, their scat would be a dead giveaway. Its texture and formation are excellent indicators of what a deer has been eating. During the summer, individual pellets are often lumped together due to the moisture content of their summer diet (grasses, clover, alfalfa, apples and other herbaceous food). As winter approaches, deer transition to a diet of twigs, leaves and acorns which results in the formation of individual, dry pellets. At this time of year, it is possible to find both forms of deer scat.
The low water levels in our ponds this fall do have one benefit – visitors leave obvious signs in the exposed muddy banks. It is fairly astounding how much nocturnal and crepuscular wildlife regularly visits these spots and remains undetected by humans under normal conditions.
If you live near a stand of Red Oak trees, your chances of seeing a Porcupine this fall are greater than average. At the end of August, when the apple supply has dwindled, Porcupines move on to important new food sources – acorns and beechnuts. While American Beech trees in central Vermont have not produced a bumper crop of beechnuts this year, Red Oaks are experiencing a very heavy mast crop. These acorns provide sustenance for many animals – Black Bears, Red and Gray Squirrels, Eastern Chipmunks and other small rodents, White-tailed Deer and Wild Turkeys, to name a few.
Porcupines are typically one of the first acorn consumers, as they are able to climb oaks and eat the acorns before they drop and are accessible to many of the other animals that are limited to foraging on the ground. If you see the tips of branches nipped off with acorn caps (but no acorns) still attached lying under an oak tree, it’s likely that a Porcupine has been dining in the tree and discarding branches after scooping out and eating the acorns.If the tree is large, the Porcupine may reside in the canopy for several days. (Thanks to Emma for photo op.)