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Animal Signs

How Owls Locate Prey Under the Snow

1-26-16  barred owl imprint  067An owl’s range of audible sounds is not unlike that of humans, but an owl’s hearing is much more acute at certain frequencies, enabling it to hear even the slightest movement of their prey under two feet of snow. When a noise is heard, the owl is able to tell its direction because of the minute time difference in which the sound is perceived in the left and right ear. If the sound is to the left of the owl, the left ear hears it before the right ear. The owl turns its head so the sound arrives at both ears simultaneously, at which point it knows its prey is right in front of it. Owls can detect a left/right time difference of about 0.00003 seconds.

Once an owl has determined the direction of its next victim, it flies towards it, keeping its head in line with the direction of the last sound the prey made. If the prey moves, the owl makes corrections mid-flight. When about two feet from the prey, the owl brings its feet forward and spread its talons, and just before striking, thrusts its legs out in front of its face and often close its eyes before the kill. (Photo: barred owl wings and feet imprints; inset: barred owl ear opening.)

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Cougars in New England

1-15-16  cougar tracks  022Are there cougars/mountain lions/pumas/panthers/catamounts (all common names for the same species) in the Northeast? There have been many sightings in every New England state, but official Class 1 confirmation (body, photographs or DNA) only in Connecticut (2011), Massachusetts (1997) and possibly Vermont (1994-mixed DNA results). It depends on whom you talk to, but the consensus of most wildlife biologists is that there may not be a breeding population yet, but they are here (some thought to be of captive origin). There is no question that cougars are extending their range eastward. Through DNA analysis a cougar killed by a car in Connecticut in 2011 proved to have come from the Black Hills of South Dakota. It had traveled about 2000 miles to the East Coast over 2-3 years.

A recent sighting by a friend had me out on snowshoes recently, trying to find traces in the woods where she had had an excellent view of what she identified as a juvenile cougar crossing the road in front of her car. The pictured tracks are what I found and followed. They are definitely cat tracks! Further investigation revealed several sites where parts of a deer had been cached, with typical (of a cat) sheared deer hair (see photo insert) evident. Unfortunately, there was no scat to be found, so adequate DNA wasn’t available for analysis, and thus, it is but one of 50 to 60 reported-but-unconfirmed cougar sightings that Vermont gets each year. It may be officially unconfirmed, but there is no question in my mind which species of cat I was tracking. (Thanks to Squam Lakes Natural Science Center for cougar photo op.)

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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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Red Squirrels Dining on Black Walnuts

1-4-15 black walnut 145The method in which a nut has been opened depends on both the species of nut as well as the species of animal that opened it. To complicate things further, it can be difficult to ascertain who opened a nut as a given species, such as the Red Squirrel, often has more than one way of opening a nut. However, a given squirrel usually chooses one way to open a nut and consistently uses that method, so that if you come upon a pile, or midden, of nuts eaten by a Red Squirrel, the nuts will most likely all have been opened in the same way.

The beveled edges on the hole in the pictured Black Walnut, the fact that it was opened from both sides (leaving the dividing rib between the two sides intact), and the central location of the holes are indications that a Red Squirrel dined on the nutmeat. The chewing of open, jagged holes on either side of a nut is a Red Squirrel’s most common method of opening a nut. Gray Squirrels tend to remove the entire side of a walnut, as opposed to chewing a hole in it.

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Meadow Vole Nests

meadow vole nest  089Meadow voles (Microtus pennsylvanicus), tiny mouse-like rodents, spend a majority of their time on the surface of the ground, particularly in moist fields filled with grasses and sedges. They have elaborate runways through the vegetation – well-worn trails about the width of a garden hose which they keep mowed down with their incisors. Latrines of small brownish-green pellets can be found intermittently along the trails.

Most meadow vole nests are constructed out of dried grasses, also on the surface of the ground, although they are sometimes built at the end of shallow burrows. When above ground, the nests are often located in the center of a grass tussock, where they are less apt to be flooded. When there is snow on the ground they are a bit easier to find, as the heat of the voles inside the nest melts away the snow, forming a chimney that sometimes reveals the nest below.

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Good Winter For Meadow Voles – Not So Much For Woody Plants

4-16-15  meadow vole sign 009Warming temperatures have revealed the considerable amount of activity that occurred under the protective deep layer of snow this past winter. In addition to a multitude of exposed meadow vole runways, there are ample signs of the voracious appetite of this small rodent. Given that more than 90% of a meadow vole’s diet consists of vegetable matter, that it can eat more than its own body weight in 24 hours, and that it breeds throughout the year, it is no surprise that the bark of many woody plants was consumed this winter, resulting in much girdling, and thus the demise, of many shrubs and saplings.

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Raccoon Latrines

4-1 raccoon latrine2 IMG_2714Raccoons defecate in communal sites called latrines. Often these latrines are located on a raised, flat surface or at the base of a tree. Over time, the scat accumulates. Should you come upon a latrine, it’s best not to investigate too closely, as raccoon feces harbor roundworm (Baylisascaris procyonis) eggs which can be easily ingested and cause harm (serious eye disease, spinal cord or brain damage, or even death) to humans. One of these roundworms can produce more than 100,000 eggs a day, and the eggs remain viable for years in the soil.

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