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Fishers

Forest Floor Mystery: Pellets? Old Scat? Cache?

6-15-16   bones 378

Lying at the base of a large Eastern Hemlock I recently found two piles of bleached bones.  One pile consisted of mostly vertebrae; the other pile had numerous tibias, humeri and ribs.  All were the appropriate size and shape to have come from several Eastern Chipmunk skeletons – at least four or five.   How did they end up in two distinct piles?

The lack of any fur indicated that regardless of how these bones came to be here, they were deposited quite a while ago.  The lack of any partial skulls or jaw bones and the large number of bones in each pile led me to believe that these were not the remains of two pellets that had been regurgitated by resident Barred Owls. No wild owl pellet I’ve ever dissected, including the large pellets cast by Snowy and Great Gray Owls, has contained even half this many bones, and most contained at least part of a jaw bone.

If not pellets, then scat?  How likely is it that a predator could catch and consume multiple chipmunks rapidly enough so that they would end up in the same pile of scat?  One feasible explanation could be that a fox, coyote or fisher preyed on young, inexperienced chipmunks, but the bones were adult-size bones.

Perhaps these two piles are the remains of a predator’s cache – perhaps a bobcat?

The possibilities are endless as to how this chipmunk graveyard came to be.  However, none of the theories proposed here can explain the dissimilarity between the types of bones in each pile.  If any naturally curious readers have insight into this phenomenon, your thoughts are welcome!

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Fisher Raids Wood Duck Nest Box

4-19-16 fisher & wood duck box by Alfred Balch Fishers are rarely seen, as they tend to travel in wooded areas and not expose themselves in open areas. However, this fisher was so intent on getting a meal that he threw caution to the wind.  Fishers are generalist, opportunistic hunters and scavengers, consuming a wide variety of animals and plants. Basically, if it can catch it, a fisher will eat it – amphibians, reptiles, invertebrates, birds and bird eggs, and mammals (snowshoe hares are at the top of the list, but rabbits, squirrels, small rodents, shrews, and porcupines are common prey).

Between its keen sense of smell, and its acrobatic abilities (due to the flexibility of its hind feet, which can be turned 180°), a fisher is able to take advantage of prey and access food wherever it may be – in the tallest tree, or, in this case, a wood duck nest box.

Noted New Hampshire naturalist/tracker/videographer, Alfred Balch, succeeded in documenting the pictured fisher swimming out to an active wood duck nest box, climbing inside and exiting with a wood duck egg gently held in its mouth.  It was observed doing this more than once.  Considering that wood duck clutches consist of anywhere from 6 to 16 eggs, this fisher’s stomach was probably full by the end of the day. The wood duck is the only duck in North America that regularly produces two broods in one season, so hopefully the second clutch will escape the fate of the first.  (Photos by Alfred Balch)

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Scent Posts

2-17-16 scent posts 026Scent 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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American Martens in Northern New England

pine marten2 by Laurie Stokes

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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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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The Short Life Span of Ruffed Grouse

1-8-16  fisher and grouse 177Ruffed grouse typically have a short life span; few live to be three years old. By mid-August about 60 percent of the grouse hatched that year are lost to predators, weather extremes, disease, accidents (such as flying into windows) and hunters. Less than half of the surviving young survive through the winter to have a chance to breed in the spring, and less than half of those that survive long enough to breed make it to a second mating season. The hazards for a ruffed grouse are many, with predation at the top of the list.

Birds of prey, especially the goshawk and great horned owl, take many grouse, but terrestrial hunters such as foxes, coyotes, bobcats and fishers also take advantage of this plentiful food source. Along with hares, porcupines, squirrels, mice and voles, grouse are one of the fisher’s preferred foods. A fisher managed to capture a ruffed grouse in the pictured scene, leaving only tracks and a few tell-tale feathers to tell the story.

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Fishers Eating Fruit & Marking Territory

11-20-15 fisher scat 134When one thinks of fishers, meat-eating predators come to mind. While it is true that the fisher is a generalist, opportunistic hunter and scavenger, and feeds on any prey it can catch and kill (snowshoe hares, rabbits, squirrels and other small rodents, birds, bird eggs, smaller weasels, shrews, porcupines, raccoons, amphibians, reptiles, carrion and a very occasional cat or chicken), it also consumes fruit and nuts, especially when prey is scarce.

Given the amount of apples that are available this fall, even if prey isn’t hard to find, it is not too surprising to see fisher scat composed solely of apples at the base of this scent marking post (confirmed by fine fisher hairs at the very tip of the stump as well as scat).

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


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