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Archive for October, 2011

Bald-faced Hornet Nest

If you find a  football-size (or larger), gray, papery structure attached to the branches of a tree or shrub, you’ve probably discovered the nest of a bald-faced hornet. (The only other hornets that build a similar nest are aerial hornets, and their nests usually have wider strips, and less of a scalloped appearance than those of bald-faced hornets.)   This structure is actually a nursery, filled with several horizontal layers of hexagonal cells, in which eggs are laid and larvae are raised.  These horizontal layers are surrounded by a multi-layered envelope, which, like the cells, is made of masticated wood fiber from weathered wood such as fence posts and hornet saliva. The different colors reflect the different sources of wood that have been used.  Although only the queen bald-faced hornet survives over winter (in a rotting log or other protected spot), the workers do not die until  freezing  temperatures have really set in, so wait for another month before approaching a nest!

 


White-tailed Deer and Snow

In the past 24 hours the first storm of the season dumped 4”- 6” of wet snow on the ground at higher elevations in central Vermont and New Hampshire.  Conditions which produce the juxtaposition of red maple leaves, snow and deer  tracks don’t occur every year.  White-tailed deer are very active in the fall — they are feeding heavily and accumulating fat for the  winter and the impending breeding season, or rut.  While a few inches of snow don’t pose much of a challenge for browsing deer, once the snow is fairly deep, their travel is curtailed and deer congregate in yards – densely canopied conifer stands, where protection from the wind and the presence of well-worn deer trails help decrease the amount of energy they expend in order to survive.


Ruffed Grouse Crop & Gizzard: the initial steps of digestion

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Some birds, especially those that eat seeds, buds, leaves and nuts, such as ruffed grouse, eat food very rapidly, faster than it can be passed through the digestive system.  These birds usually have a pouch-like crop  where food is kept to be digested later, when the birds  are not out in the open, susceptible to predators.  When the grouse roosts, food leaves the crop and passes through the stomach, which has two parts: a proventriculus – an enlarged area where gastric juices begin breaking down the food, and a ventriculus, or gizzard, which is very muscular, and crushes hard items, such as nuts. According to Roger Pasquier, in Watching Birds, the evolution of an internal means of breaking down food has enabled birds to do away with the heavy teeth and jaws found in fossil birds.  Many birds, including grouse, swallow sand or gravel (you’ve probably seen birds on dirt roads doing this) which passes into the gizzard and helps grind up hard food items.  One photograph shows the contents of a grouse’s crop – bits of leaves, what I think are huckleberries, barberry fruits, buds and a twig—all intact.   If you look closely at the photograph of the gizzard contents, you will see, in addition to crushed fruits and seeds (and two pieces of what appear to be nuts in the upper left) that the grouse recently consumed, tiny bits of sand (upper right) which help in the grinding process. 


Balsam Fir Cones

Balsam fir’s (Abies balsamea) cylindrical cones are very distinctive, in that they stand erect on year-old branches at the top of the tree, and are not pendant, like the cones of many conifers.  They differ in another way as well, for after the seeds mature and the cone opens to release them in the wind, the cone disintegrates, with the scales falling to the ground, leaving candle-like spikes on the tree. Some historians think that these spikes, when snow-covered, inspired the Germanic people to decorate trees with candles or lights.


Woolly Bears

Legend has it that the more black at either end of a woolly bear, the harder the winter that lies ahead.  Truth be known, the woolly bear caterpillar (larval stage of the Isabella Tiger Moth) molts its skin up to six times, and each time a brown section is added; thus, the longer the summer, the greater the ratio of brown to black on a woolly bear.   A mostly-brown caterpillar is more an indication of an early spring or late fall, rather than a forecast of the coming winter’s severity!


Common Eider

On a recent visit to Peak’s Island, Maine, I observed many common eiders (the largest ducks in the Northern Hemisphere) bobbing in the ocean just off  the rocky coast.  Every so often one would dive and retrieve a mussel, crab or sea urchin which it would then consume.  At low tide, both drakes and female eiders would settle on the seaweed-covered rocks, where the drakes’ plumage (photo) seemed to blend perfectly.


Running Clubmoss, Lycopodium clavatum

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Common clubmoss (Lycopodium clavatum) is, like most clubmosses, small, evergreen and perennial. Some species of clubmosses resemble miniature pine and cedar trees, or giant mosses. Common clubmoss’s horizontal stem creeps along the forest floor, with upright stems arising from it.  This “fern ally” (related to but not a true fern) reproduces with spores, not seeds, that are found in cone-like structures called strobili located at the end of stalks, looking somewhat like a candelabra.  At this time of year, if you tap one of the strobili, you may see a yellow cloud of spores released into the air.


Damselflies Laying Eggs

Different species of damselflies and dragonflies emerge throughout the warmer months of the year.  Entomologists lump them all into three categories  —  “spring,” “summer” and “fall” fliers.  Fall fliers generally emerge in mid-summer and fly through early to mid-October.  Recently, at a nearby pond, it appeared that damselflies were taking advantage of the lingering warm days by mating and laying eggs before cold weather set in.  Nearly every cattail leaf was loaded with several pairs of damselflies, most of which were still attached to one another (the males continue to grasp the females after mating with them to prevent the removal of their sperm by other males).  When I returned the next day, there wasn’t a damselfly in sight.


Beavers Grooming

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Usually inside their lodge, but occasionally outside, beavers spend hours a day coating their fur with a self-made water-repellent liquid.  This is accomplished by rubbing an oily secretion from their anal glands into their fur, thereby waterproofing it.  For the first month or two of life, young beavers don’t produce this substance, and their parents must apply their own secretion to the coats of their young.  Beavers groom themselves wherever they can reach, but rely on other family members to waterproof their backs, which is what is going on in the last photograph of the series.


Eastern Chipmunk Grooming

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Chipmunks are known for their personal hygiene.  If you take the time to sit and observe them, you will find that much of their grooming takes place after eating, when they’ve been holding a seed or nut in their front feet .  They often sit up on their haunches and proceed to lick the insides of both front paws, after which they typically rub their face, presumably to clean whiskers or perhaps facial hairs that might have gotten a bit of food on them.  Chipmunks also take dust baths, during which they saturate their fur with sand and then shake it out, in an attempt to rid themselves of the mites and fleas that are known to plague them.

 


Ribbed Petiole Poplar Gall

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If you look at enough Trembling  Aspen (Populus tremuloides) leaves (and to some degree, those of other poplar species), you are bound to come across some that have an oval swelling about the size of a pea where the leaf  and stem, or petiole, meet.  This swelling is a gall – an abnormal plant growth caused by chemicals coming from the moth (Ectoedemia populella) that laid an egg at this spot this past summer, or from the chewing of the hatched larva as it bored its way into the stem of the leaf.  This gall provides shelter and food for the developing larva, which will, after the leaf falls, go down into the ground to pupate.  An adult moth will emerge next  spring.   

 


Tree Bud Formation

 

Because tree buds tend to swell and increase greatly in size in the spring, this is often the season when we first notice them and assume that this is when trees produce them.  If you look in the axils of leaves on any tree right now, you will see full-size buds that were formed this summer.   These little packages of miniature leaves, branches and sometimes flowers, will remain on trees all winter, tightly closed and often protected from the elements by modified leaves called bud scales.  Come spring, when trees are once again taking up quantities of water, their buds will swell, scales will fall off (leaving bud scale scars), and tiny, pristine leaves will appear.  (Photo is of American beech, Fagus grandifolia, bud.)