An online resource based on the award-winning nature guide

November

Raccoons Preparing For Winter

Much like black bears, raccoons develop a voracious appetite in the fall and accumulate a life-sustaining layer of fat as a result (which comprises 50% of their weight).  Although raccoons are opportunists and will eat just about anything (except tomatoes), nuts (acorns, beechnuts, hickory nuts and hazelnuts, especially) and corn are the food of choice at this time of year.

When the temperature consistently drops to 26-28° F. raccoons typically seek shelter in dens (hollow trees, woodchuck and fox burrows). They are not true hibernators, but do enter a state of torpor for weeks and even months at a time when the temperature is low, the snow is deep and the wind is blowing.  It’s not unusual for several raccoons, usually relatives, to den together.

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Wattles, Caruncles & Snoods

Wild tom turkeys have a number of ways of impressing hens in addition to displays involving their feathers. Among them are wattles, caruncles and snoods — fleshy protuberances that adorn their throats and beaks.

A large wattle, or dewlap, is a flap of skin on the throat of a male turkey. The bulbous, fleshy growths at the bottom of the turkey’s throat are major caruncles. Large wattles and caruncles have been shown to correlate with high testosterone levels, good nutrition and the ability to evade predators, which makes the genes of a tom turkey with them very desirable to a female.

The snood, another fleshy outgrowth which hangs down over the male’s beak, is normally pale and not very long. When he starts strutting and courting a hen, the tom’s snood (and caruncles) becomes engorged with blood, making it redder and longer. This impresses both male and female turkeys –the males avoid or defer to him and the females’ interest in him is heightened. A longer snood has also been correlated with a lack of internal parasites, making toms with large snoods even more irresistible to hens.

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Mystery Photo

What do you think made this six-inch-long impression in the snow?  Please enter guesses under “Comments” on the Naturally Curious blog (scroll down). Answer will be revealed on Monday, November 25.

(Photo by artist Susan Bull Riley – http://susanbullriley.com/ )

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.


Bird Nests Revealed

Deciduous leaves have fallen, revealing bird nests that were right under our noses all summer without our even knowing it.  In addition to building in specific habitats and constructing different sized nests, each species of bird uses a combination of building material that is slightly different from every other species. Because of this, the material a bird uses to construct its nest can be diagnostic as far as determining what species built the nest.  Is the nest lined with rootlets? Are grape vines incorporated into the nest? Is moss covering the outside of the nest?  Is there a shed snake skin woven into the nest? The answer to these questions and others can help narrow down the list of possible builders.

This is the time of year to look for nests and try to determine, with the help of a good field guide such as Peterson’s Field Guide to Bird Nests, the identity of the birds that built them.  (Be aware that possession of a bird nest, egg or feather of most migratory birds, even for scientific research or education, is illegal if you do not have a Federal Migratory Bird Scientific Collecting Permit.)

Sometimes you’ll find material in nests that surprise you — some contain man-made, as well as natural, materials. Among the most unusual examples of this are a nest built solely out of barbed wire by a Chihuahuan raven in Texas and the pictured clothes hanger nest built by a crow near Tokyo and photographed by Goetz Kluge.

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Some Ways Mammals Stay Warm In Winter

When temperatures drop significantly, mammals that stay active in the winter have a variety of ways to keep warm, one of which is to have layers of insulation to prevent their body heat from escaping.  Often there is a layer of fat under the skin. In addition to providing a source of energy, fat doesn’t transfer heat as well as other tissues such as muscle or skin, and thus helps to insulate an animal’s body. The next layer consists of a short, dense coat of underfur which is filled with air pockets that provide insulation.  Lastly there frequently is a third layer of oily, water-repellent guard hairs which excel at keeping out water. They are often transparent and hollow, providing extra thermal insulation.

Voles, mice, shrews and red squirrels use elaborate tunnels systems under the snow to escape cold temperatures and strong winds.  Flying Squirrels huddle together in groups to keep warm. Shivering is a warming technique used by many mammals, including humans.  And some active animals, like the pictured Gray Squirrel, simply find a sheltered spot in the sun, close their eyes, and soak up the warmth!  (Thanks to Jody Crosby for photo op.)

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Common Loons Migrating

Much has been learned about the fall migration of Common Loons in northern New England.  They are diurnal migrants, parents generally migrate first, young loons remain on the lakes where they were born or adjacent lakes until close to when the lakes freeze up, and the greatest number of fall migrating loons occurs in late October and the first half of November.

The very large loons in Maine, New Brunswick, and eastern New Hampshire do not migrate far and primarily over-winter in the Gulf of Maine, while smaller loons from other New England states and New York migrate to Long Island Sound south to New Jersey. Many loons migrate singly but group together on larger lakes referred to as staging areas. Overland migration altitudes range from a mile to a mile and a half, while over water loons often migrate within 300 feet of the surface.  One-and two-year old Common Loons remain throughout year on wintering sites. (Cornell’s Birds of North America)

(Photo of adult and juvenile Common Loons taken in early October, just as molting was beginning at the base of the adult’s bill. By December most adult loons have fully molted into their gray winter plumage.)

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Spider Winter Survival Tactics

Spiders are cold-blooded, or ectotherms. Their body temperature is regulated by external sources and can vary with the environment without doing them any harm. When cold weather comes spiders that overwinter as adults adapt in several ways. Their metabolism slows down and they become less active. Eventually they become dormant, entering diapause, a hibernation-like state.  At the same time, they start producing glycol and protein compounds which act as antifreeze and lower the temperature at which their cells will start freezing.  A spider has to get to at least 23 degrees F. to freeze, and sometimes considerably lower.

Where a spider spends the winter depends in large part on the species. Some seek shelter in places where temperatures remain a little warmer than outdoors, such as in leaf litter, rock piles, building cracks and under loose bark. To help block cold wind, some will even build themselves a little pod with their silk, enclosing themselves until it is warm enough to become active again.  (Photo:  spider in silk pod behind loose bark)

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