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Scent Marking

White-tailed Deer Scent-Marking

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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.)

 

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Black Bears Communicating

6-21-17 black bear by Alfred 2017-05-24 15.35.19Black Bear males are not shy about making their availability and intentions known to the opposite sex. Their most prevalent means of communicating this information is to leave their scent on trees (as well as other structures, such as telephone poles– see photo) by scratching them with their claws, biting them and rubbing on them with their shoulders, back and neck. Often they will use the same marking tree year after year, with signs accumulating on the tree.

Both males and females mark trees year-round, but at this time of year, at the peak of their mating season, males are especially active markers, in order to convey their social identity, reproductive status and location to female passersby. One might consider such marking trees as ancient “scratch.com” mating sites. If you find one, be sure to look for stray hairs that have been inadvertently left behind. (photo by Alfred Balch)

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Classic Fisher Sign

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Fishers are one of the most rewarding mammals to track as they leave so many signs. One of the most common ones, other than their tracks, is their scent posts. This is where a fisher rubs itself, anointing the substrate with its scent as it marks its territory. Young saplings often serve this purpose. The fisher rubs and rolls on a young tree, often a conifer, usually breaking a few branches.

If you see a scraggly-looking sapling in the woods, and there are fisher tracks nearby, examine the sapling closely for fisher hairs that often get caught on the branches when a fisher rubs against them. More often than not, the fisher will also mark the tree with a bit of scat or some urine. Fishers are very adept at controlling the amount of feces they leave, often excreting very small portions as markers throughout their travels.

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Red Foxes Scent Marking & Breeding

2-9-16  red fox marking 017Red 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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Female Eastern Coyotes In Estrus

1-27-16 coyote in estrus 036Female Eastern Coyotes come into estrus only once a year, usually in late winter for two to five days. For two or three months prior to as well as during this time, males roam widely and scent marking by both males and females increases. During their mating season, coyotes often travel in pairs, and it is not unusual to find scent posts where both male and female have scent marked with their urine. (The female’s urine is often tinged with blood.) The percentage of females that breed in a given year (typically 60% to 90%) depends upon the availability of food and their physical condition.

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Fishers Scent Marking With Scat

1-13-16 fisher bed & scat 002Many animals communicate by scent marking in order to stake out territory. This is done through specialized glands on various parts of their bodies as well as with scat and urine. In addition to defining territory, scent marking may also communicate additional information such as the sex, reproductive status or dominance status of the territory-holder. Fishers are a prime example of a scent marking predator. In addition to scent marking with glands on their feet, fishers rub, urinate and deposit scat often near or on raised surfaces (stumps, rocks, saplings), where their scent is likely to be widely dispersed. Frequently scat will also be found near a fisher’s resting spot.

When marking with scat, fishers are somewhat unusual in that it appears that they can control the size of the scat they leave. While field guides say fisher scat is between two and seven inches in length and roughly ¾” in diameter, this is not always the case. (Neither is it always dark and twisted – some fruit, such as rotting apple in the pictured scat, will cause it to be lighter colored.) One wonders what determines the size of the scat that a fisher leaves. Does it plan on marking a great deal in the coming hours, and so parcels it out in bits and pieces so as not to run out? Or is a large amount not always necessary if it has back-up scent from its feet and body? The pictured scat (to the right of the depression a fisher left while resting at the base of a tree) is less than an inch long, and about 1/3” wide — roughly the size of a white ash seed. Chances are that after spending enough time in one place to melt crusty snow the fisher was capable of leaving far more feces, but it chose not to.

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Meadow Voles Food for Coyotes

1-11-15 coyote  192When there is deep snow on the ground, white-tailed deer are often preferred-eating for eastern coyotes, with snowshoe hares not far behind. While small rodents are also consumed during the winter, they make up a larger proportion of a coyote’s diet during spring, summer and fall. With only a few inches of snow on the ground currently, meadow voles are still very vulnerable to predation, as the tufts of grass where they tend to nest are still visible.

Tracks indicate that a coyote stopped to investigate numerous grass tussocks scattered throughout a nearby field recently. Near several of these clumps of grass were slide marks (see foreground in photo) where the coyote had jumped, landed and slid. The groove made by the coyote’s sliding foot always ends with a foot print. At this particular site, the coyote had pounced, slid and then dug and uprooted a nest, possibly procuring a vole, but leaving no trace of success behind. What it did leave behind was scat (3 o’clock in photo), with which the coyote claimed ownership of the site.

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