An online resource based on the award-winning nature guide

Archive for November, 2016

Mouse Meals

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Deer and White-footed Mice are viewed negatively due to their association with Deer, or Black-legged, Ticks, carriers of Lyme Disease.  However, these mice are also beneficial, not only as a staple prey food for many predators, but as a vital contributor to the health of our forests.

Mice help spread various kinds of fungi by eating the fruiting bodies (which contain spores) and eventually excreting the spores.   Certain fungi colonize the root system of trees, creating a symbiotic relationship called mycorrhizae. The fungus provides increased water and nutrient absorption capabilities to the tree while the tree provides the fungus with carbohydrates formed from photosynthesis. For many temperate forest trees, these fungi have been shown to be an essential element in order for them to prosper. By consuming fungi and dispersing their spores, these small rodents are inadvertently contributing to the vitality of our forests. (Note: look for the tiny incisor marks of mice in the devoured fungus.)

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Modern Technology Reveals Snowy Owl Winter Behavior

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With the arrival of this winter’s first Snowy Owls in New England comes a renewed interest in the winter ecology of these birds of prey. An organization called Project Snowstorm (www.projectsnowstorm.org ) gathers detailed information every 30 seconds on the movement of Snowy Owls that they have outfitted with a backpack harness containing a solar transmitter. These transmitters use the cellular phone network, not a satellite, and when they are out of range of a cell tower, they store information which is transmitted when the bird is back within cell coverage territory – even if it’s years later.

The information that has been gleaned from this modern technology is stunning, and has allowed us to know far more about the behavior of Snowy Owls in winter. Some Snowy Owls stay within a quarter mile of where they are banded; others cover hundreds of miles within a few weeks. Some Snowy Owls spend much of the winter out on the frozen Great Lakes, where they prey on waterfowl they find in the cracks in the ice that open and close repeatedly.   Not only has it been confirmed that Snowy Owls feed heavily on birds in the winter (especially ducks, geese, grebes and gulls), but their use of channel markers and buoys as hunting perches while they seek prey over the open ocean at night has been documented.

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Fall Beaver Lodge Renovations

11-24-16-beaver-lodge-049a1681Beaver lodges undergo a great many renovations in late fall. If the water level is high, the floor of the lodge and the roof of the sleeping chamber are raised. The lodge is strengthened with the addition of new material to the roof. Long, debarked sticks are pulled up vertically to the apex of the lodge and shorter sticks are then jammed into the lodge in order to pin it all together. When the roof of the lodge is two feet thick or more, mud and vegetation are applied on top of it.

Most of the decomposing plant material used to reinforce the roof of the lodge is dredged up from all around the base of the lodge (increasing the area’s water depth). The lodge is then coated with mud gathered at the bottom of the pond. This final coating of mud is of utmost importance – eventually it will freeze as hard as cement, providing protection from predators such as coyotes that can walk across the pond to the lodge once the water freezes. (A layer of mud is applied to bank lodges (see photo), as well.)

A beaver reaches all portions of the roof by holding the mud beneath its chin with its front feet, and walking upright on its hind legs, using its tail as a brace. The mud is then applied and smoothed over with its front feet. At the top of the lodge, an area about 15” wide is not coated, allowing fresh air to filter down into the roof of the sleeping chamber. On very cold winter days, the escaping moist warm air from the beavers’ breath can be seen drifting from this “chimney” at the apex of the lodge.

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Fishers Crossing Logs

11-25-16-fisher-tracks-049a1848The first snow that sticks on the ground is cause for celebration, if only because it allows you to know so much more about what goes on in the woods and fields that surround you than you would know if it never snowed. At this point the snow isn’t deep enough to distinguish tracks very well in the leaf litter, but thanks to the fisher’s propensity for crossing logs (which are relatively smooth, an excellent substrate for tracks, and retain scents well), one resident’s presence was announced loud and clear recently.

Fisher have large, wide feet with five toes on each foot and semi-retractable claws. This makes them well adapted for walking on snow, climbing trees and grasping and killing prey. (They are also capable of rotating their hind feet nearly 180 degrees, which allows for a headfirst descent from trees.) Their track is very distinctive, and can be quite common in forested areas of the Northeast.

Usually, if given the option, fishers will choose walking on a log over walking on the forest floor. Why would they have developed this preference? There often is no water where this occurs, so it’s not done in an effort to avoid wet feet. My best guess as to the purpose of this behavior is scent-marking. Fishers have been observed sliding along logs on their bellies, as they rub the scent of their anal glands along the top of the log. The fisher scent-marks with cheek, abdominal, neck, flank, and plantar (feet) glands, in addition to anal glands. A fisher leaves its scent with every step of its hind feet, and if rotting logs are superior scent-absorbers, it may be why fishers choose them over the forest floor.

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The Persistent Capsules of Lady’s Slippers

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While the pink, yellow and white pouches of lady’s slippers no longer grace the landscape, the results of their pollination do. Capsules rising above the surrounding ground on single stalks can be seen where lady’s slippers used to reside. These fruits will persist through the winter and even into the next flowering season.

A close look reveals slits along the length of the capsule. Wind, rain or wildlife passing by will shake the capsule, causing thousands of dust-like seeds to be dispersed. Because they carry no food reserves, these seeds must establish a relationship with a mycorrhizal fungus in order to germinate. (photo: Showy Lady’s Slipper flower and fruit)

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An Opossum’s Opposable Thumbs

11-22-16-opossum-hind-foot3-untitled-1Virginia opossums have expanded their range into northern New England, but are still not commonly seen, except, perhaps, lying on roads where they met their demise. There is much to admire about opossums: they are the only North American marsupial, they have more teeth than any other North American land mammal (50) and they possess a prehensile tail and opposable thumbs (both of which are rarities among non-primates).

The recent discovery of a road-killed opossum provided me with an opportunity to examine its feet at close range. An opossum’s front feet have five toes, each bearing a nail. Their hind feet also have five toes, but only four of them have nails. The fifth toe, or “thumb,” lacks a nail and is opposable, allowing opossums to grasp branches and to climb. If you see their tracks, the hind foot is easily discernable from the front due to the fact that the thumb is at a 90-degree angle to the other toes.

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