An online resource based on the award-winning nature guide

Archive for October, 2012

Wasps Still Flying

The lingering warm weather and the few remaining flowers (such as the mustard in the photograph) have allowed worker wasps to extend their lives this fall longer than many years, for once several hard frosts hit, they will die. Unlike honeybees, the queen of social wasp colonies lives only about a year, but that is longer than the workers. In the late summer the (old) queen stops laying eggs and the colony soon begins to decline. In the fall, mated female offspring of the queen seek overwintering sites such as rotting logs. In these protected spots they tuck their wings and antennae under their bodies, and hunker down for the winter. The remainder of the colony does not survive the winter. If predators such as spiders don’t kill the new queens, and if they don’t emerge early due to a warm winter and starve due to lack of food, the young queens begin building nests and laying eggs in the spring.


American Hornbeam

American Hornbeam (Carpinus caroliniana) goes by many names, including Musclewood,  Bluebeech and Ironwood. Its smooth, gray bark that appears twisted and somewhat muscular is very distinctive. This member of the Birch family usually has several trunks, and is usually less than 30 feet tall. Its fruit is in the form of clusters of small nutlets, each attached to a papery bract. A good seed crop is produced every three to five years, at which time it benefits ruffed grouse, cardinals, evening grosbeaks and American goldfinches, all of whom prefer it over many other seeds.


Autumn Meadowhawks Mating

Meadowhawks are the only small red dragonflies seen in New England (most males are red, most females are brown).The latest species of dragonfly flying in the fall in this area is the Autumn Meadowhawk (Sympetrum vicinum), which doesn’t emerge until mid-summer. It seems a bit incongruous to observe these dragonflies not only flying, but mating and laying eggs in late October, but that is exactly when you can expect to see them. Until there have been several hard frosts, these winged masters of the air are able to keep active by basking in the sun and warming their flight muscles. The two pictured Autumn Meadowhawks are copulating in the typical “mating wheel” fashion, with the male grasping the female behind her head while the female places the tip of her abdomen at the spot on his abdomen (the seminal vesicle) where he stores his sperm. The female Autumn Meadowhawk lays her eggs in tandem with the male (his presence prevents other male meadowhawks from replacing his sperm with their own).


Piles of Snow Fleas

We tend to associate snow fleas, a type of springtail, with winter, as that is when we can easily see their tiny black bodies against the white snow.   However, these insects don’t magically appear when it snows – they are in the leaf litter and soil all year round.  Snow fleas are considered to be one of the most numerous land animals on earth, with several hundred thousand inhabiting a cubic yard. Even so, it was with amazement that I found several piles of snow fleas at the base of my garage door this morning – it’s the wrong time of year, and most of the individual snow fleas were not scattered apart from each other.  Several solid black patches of snow fleas, one patch measuring roughly 6” by 2 ½ ”, piled 1/8” high, had appeared overnight.  Something about the warm, humid air this morning may have caused them to leave the safety of the forest floor and for some unknown reason gather in piles on the cement.  Once the garage door was raised, the piles disappeared within five minutes, as each tiny snow flea catapulted itself several inches away and disappeared into fallen leaves.


Snail and Slug Eggs

Snails and slugs are very similar, except for a slug’s lack of a shell.  Both are hermaphroditic, possessing male and female reproductive organs.  In some species an individual may behave as a male for a while, then as a female. In a few species, self-fertilization occurs. Some species mate and lay eggs in the spring, some in the fall. Most snails and slugs that hatch in the spring can begin egg laying in the fall. The eggs of both snails and slugs are tiny, white or cream-colored, round and laid in roughly one-inch diameter clusters of 30 or so eggs. Look for these clusters under rotting logs, where they are protected from drying out as well as from freezing.  (Remember to place the log back exactly as you found it.)


Avian Digestion

This slideshow requires JavaScript.

What happens to food after a bird swallows it? It may be stored in their crop, a pouch which is actually an enlarged part of its esophagus that some species of birds (and bees, fish and earthworms) have, or it may go directly to their stomach.  Birds have a two-chambered stomach.  The first chamber, the proventriculus, secretes acids that help break down food, including bones. A shrike’s well-developed first stomach chamber can digest an entire mouse in only three hours!  From the proventriculus the food goes into the second chamber, which is referred to as the gizzard, before entering the intestines.  The gizzard is a muscular organ which grinds up tough food, sometimes with the help of grit that some birds ingest.  The gizzard grinds the gravel and stones against the nuts and seeds, a process which smashes the food.  Wild turkeys can actually pulverize walnuts in their gizzards!  In some species, the gizzard remains small and insignificant during the summer when their diet consists of soft food such as flesh, insects, or fruit, but it grows more powerful during the winter when seeds are their main food.


Insects in Winter

What happens to insects this time of year?  A few remain active, such as snow fleas, and some, like monarch butterflies, migrate, but the vast majority of insects overwinter in New England.  The insects that stay here are susceptible to freezing due to the fact that they cannot control the temperature of their body.  Some insects, such as woolly bear caterpillars, can tolerate having ice form in their tissues, but most insects go into a state known as diapause.  When the days start getting shorter, these insects reduce the water content of their body, as water freezes at a high temperature compared to other liquids, and replace it with glycerol, which acts like antifreeze, protecting them from freezing. (Please excuse duplicate post.  I’m testing new posting process.)


Insects in Winter

What happens to insects this time of year?  A few remain active, such as snow fleas, and some, like monarch butterflies, migrate, but the vast majority of insects overwinter in New England.  The insects that stay here are susceptible to freezing due to the fact that they cannot control the temperature of their body.  Some insects, such as woolly bear caterpillars, can tolerate having ice form in their tissues, but most insects go into a state known as diapause.  When the days start getting shorter, these insects reduce the water content of their body, as water freezes at a high temperature compared to other liquids, and replace it with glycerol, which acts like antifreeze, protecting them from freezing.  (Due to technical problems which hopefully will be resolved soon, I am unable to include a photograph with this post.  My sincere apologies.)


Common Gartersnakes Basking

This is the time of year when snakes take advantage of sunny, mild days by basking in the sun and warming their bodies.  It’s possible to come across basking Common Gartersnakes as late as November, as they are more cold tolerant than many species of snakes.  All too soon, however, they will be retreating into their hibernacula (hibernation site), where they are protected from severe cold (being ectothermic, snakes cannot control their body temperature).   To further protect them, a high level of glucose acts as antifreeze in snakes.  The ideal hibernaculum not only serves as a temperature buffer, but also conceals its occupant from potential predators, permits gas exchange, and prevents excessive desiccation.  Rock crevices, abandoned woodchuck burrows, rotting tree stumps and old foundations are favorite hibernacula for snakes and other hibernating animals.  Gartersnakes typically overwinter in groups, and some even share their hibernacula with other species of snakes, including Smooth Greensnakes, Ring-necked Snakes and Red-bellied Snakes.


North American River Otter Roll

This slideshow requires JavaScript.

In addition to their winter slides in the snow, river otters leave distinctive signs year round.  Their scat is unlike most other animal scat in that it has little form and often disintegrates into a pile of fish scales.  Sometimes river otters create what are called “rolls” —  areas near water that they repeatedly visit to defecate, urinate and roll around on the ground.  If used frequently enough, rolls become so acidic that they turn black with dying vegetation.  Being a member of the Weasel family, otters possess oil glands and waterproof their fur with oil. It’s possible that in addition to marking territory at a roll, they are distributing this oil throughout their coat when they are rolling on the ground.


Countershading

Countershading is a common color pattern in animals in which the upper side of the animal is darker than the lower side.  This color pattern provides camouflage for the animal when viewed from the side, above or below.  The counter shading pattern balances the sunlight on the animal’s back and the shadow beneath the animal so as to blend the animal’s side profile with its surroundings.  In addition, when viewed from below, a counter-shaded animal with a light belly blends into the light coming from the sky above. When viewed from above, the darker back of a counter-shaded animal blends into the darker ground colors below.   Birds (which spend a considerable amount of time in the air) such as this dark-eyed junco, as well as marine animals often exhibit countershading.


Downy Rattlesnake-Plantain

If you look at the forest floor in coniferous woods you may well discover Downy Rattlesnake-Plantain (Goodyera pubescens ).  This evergreen rosette of broad, rounded leaves gets its name from the similarity of the shape of its leaves to those of plantain, a common lawn weed.  In fact, it is an orchid, not a plantain, and is the most common species of plantain in New England. It is distinguished from other species of rattlesnake-plantains by the bright silver markings on the leaves and the broad stripe down the center of the leaves.  Each leaf lasts for approximately four years.


Woolly Bears on the Move

Although it’s fun to try to predict the severity of the coming winter by the amount of brown on a woolly bear caterpillar (the more brown = the milder the coming winter, according to folklore), the coloration of any given woolly bear caterpillar has more to do with its diet and age than the coming weather.  The more a Woolly Bear eats, the more frequently it molts, and each time it molts a portion of the black hairs (setae) is replaced by brown ones.  A Woolly Bear can molt up to six times — the best fed and oldest woolly bears, which have molted the most number of times, have the widest brown bands. (After overwintering as caterpillars, Woolly Bears pupate and emerge as small, brown moths called Isabella Tiger Moths, Pyrrharctia isabella.)


Yellow-orange Fly Agaric Mushroom

The Yellow-orange Fly Agaric (Amanita muscaria var. formosa) is common in New England, especially where conifers grow.  Out West this mushroom is often a bright red color, but in the East it’s typically orange/yellow.  When certain gilled mushrooms, including many Amanita species, first form, they are encased in a membrane called a “universal veil.”  As the mushroom enlarges and matures, the veil ruptures, with remnants of it remaining on the mushroom’s cap.  Fly Agaric fungi got their name from the custom of placing little pieces of the mushroom in milk to attract flies.  The flies supposedly become inebriated and crash into walls and die.  This mushroom is somewhat poisonous (as are many Amanita species) and hallucinogenic when consumed by humans.  The toxins affect the part of the brain that is responsible for fear, turning off the fear emotion.  Vikings, who had a reputation for fierceness, are said to have ingested this mushroom prior to invading a village.


Winter Bird Irruptions

According to the predictions on eBird’s annual Winter Finch Forecast, several species of northern seed-eating birds will be moving south this season due to a poor cone crop in the north.  As of mid-October, pine siskins (pictured), purple finches, red-breasted nuthatches and red crossbills have already been showing up in larger numbers than usual in New England, well south of their normal wintering grounds.  This type of movement is referred to as an irruption.  Because of a widespread crop failure of fruiting and cone-bearing trees in Canada, we may be lucky enough to have a glimpse of crossbills, redpolls, pine grosbeaks and evening grosbeaks this winter.   The latest to arrive at my feeders are pine siskins, whose irruptions often occur on a two-year cycle.  Their numbers in New England were great during the winters of 2008 and 2010, so the pine siskin irruption this year is right on time.


Red Squirrel Sign

If you find a mushroom hanging in an unlikely spot, such as from tree branches or tucked into the bark of a tree where it didn’t grow, it’s likely that you have happened upon the work of a red squirrel (Tamiasciurus hudsonicus).  Red squirrels are known for their habit of snipping mushrooms and hanging them from branches and rough bark in order to dry them before collecting them and caching them for dining on later in the winter.   Unlike beavers, which share their stored cache of winter food with family members, red squirrels keep their cached fungi all to themselves.


Common Juniper

Common Juniper (Juniperus communis) is one of the few evergreen shrubs in New England and has one of the largest ranges of any woody plant.  You often find it in old pastures and meadows, where its sharp needles protect it from most herbivores.   It is a member of the Pine family, and even though its fruits look like berries, structurally they are cones (with fleshy scales).  Whereas most of the cone-bearing members of the Pine family disperse their seeds in the wind, Common Juniper uses birds and mammals to do this deed.  Cedar waxwings, evening grosbeaks and purple finches consume quantities of juniper fruit, and many other songbirds are frequent visitors.  White-footed mice and white-tailed deer occasionally eat the fruit as well.  While not aiding the dispersal of seeds, humans do use the fruit to flavor gin.


Eastern Chipmunks Gathering Food

By the end of this month or the beginning of November, most Eastern Chipmunks will have gathered and stored their winter food supply underground in a special chamber which they will visit every two or three weeks throughout the winter, grabbing a bite to eat.  Up to half a bushel of nuts and seeds can be stored here, which means many trips from the food source to the larder.  In order to minimize the number of trips, chipmunks  cram their cheek pouches as full as possible.  The contents that researchers have found in one chipmunk’s two pouches include the following (each entry represents the contents of one chipmunk’s pouches):   31 kernels of corn, 13 prune pits, 70 sunflower seeds, 32 beechnuts, 6 acorns.


Sawfly Cocoon

Sawflies are often mistaken for wasps, but there are subtle differences in appearance, including the thick “waist” of a sawfly compared to the threadlike waist of a wasp.  Their common name comes from the females’ sawlike ovipositor which they use to cut into plants and lay their eggs.  Certain species of sawflies overwinter as pupae inside cocoons that they attach lengthwise to twigs.  These cocoons are fairly small (the pictured cocoon is just over ¼” long).  Sawfly cocoons persist even after the adults emerge in the spring, as they are made of very tough material.   Look for capped cocoons during late fall and winter, and empty cocoons, sometimes with the cap still attached, the rest of the year.


Juvenile European Starlings Molting

Unlike their greenish-black iridescent parents, this year’s young European Starlings had a drab gray-brown plumage through the summer.  During late summer and fall all starlings molt and black speckled feathers grow in.  There is a brief period of time when juveniles still have a pale tan head, before it, too, becomes speckled.    Even though both juvenile and adult European Starlings resemble each other by late fall, it is possible to tell this year’s young from adult birds. First-year starlings have more white speckles than adults, and their speckles are heart-shaped, as opposed to the V-shaped speckles of their parents.


Virginia Creeper

As you might assume from its appearance, Virginia Creeper (Parthenocissus quinquefolia) is in the Grape family.  This climbing woody vine clings to the surfaces over which it climbs with adhesive disk-tipped tendrils, which are actually modified flower stalks.  The disks form only after the tendril has made contact with a tree or other surface, at which point the disk secretes a cement-like substance, keeping the vine attached to the substrate long after it has died.  Although it superficially resembles poison ivy, Virginia Creeper has five leaflets (“quinquefolia”), as opposed to poison ivy’s three.  Virginia Creeper’s brilliant red fall foliage is thought to attract birds, which consume the blue-black berries and disperse the seeds.


Beavers Gathering Winter Food Supply

Shorter days and longer nights trigger a flurry of activity for beavers.  There is a lodge to be built, rebuilt, enlarged or repaired and a dam to be built, repaired or reinforced.  As, or more, important than these tasks is cutting, gathering and transporting a supply of food for winter. Once the pond is frozen, the only food available to beavers is that which they have stockpiled under the ice.   Thus, beavers spend many an autumn night adding to a growing pile of submerged branches close to the lodge.  More thought is put into the harvesting of a winter food supply than one might imagine.  Before cutting down a tree a beaver often tests its readiness by biting into the bark.  If it is not in just the right condition — for instance, if there is still too much sap in the tree — they may speed up the drying of the bark by girdling it, and returning in several days to cut it down.  If limbs and branches are stored underwater before the bark is ready, they will ferment and sour, making them unfit for food.


Juvenile Cedar Waxwings Migrating

Possibly because of the importance of summer fruits in their diet, Cedar Waxwings (Bombycilla cedrorum) are late nesters, but by late August adults have begun their migration to the southern states and Central America.  This year’s young are beginning this (roughly) 900-mile flight now, a month after their parents have left. You can often find waxwings feeding in crab apple and other fruit trees where they stop over during their flight to refuel.  Juvenile birds lack the sleek look of adults — the red wax-like feather tips for which this bird is named have not developed, and the color of their plumage is much duller than that of the adults.


Chicken of the Woods

If you see a bright orange and yellow shelf fungus on a living or dead tree, chances are that it is Chicken of the Woods (Laetiporus sulphureus).  It can grow in fairly impressive clumps of up to 100 pounds.   The pictured shelves of this fungus extend well over 20 feet along the rotting tree trunk, and this was only half of total amount present.  Chicken of the Woods doesn’t appear until well after the fungus has attacked the tree, and because it causes heart rot, the center of the living tree on which it grows is often hollow.  Young Chicken of the Woods (particularly the growing edge of the fruiting body) is considered a great find by fungi foragers, as its taste resembles chicken – hence, its common name.  Although it’s been considered one of the “foolproof four” fungi that can be eaten, similar species have recently been found which are not edible, so some people advise foraging with caution.  (Thanks to Hilary Hamilton for photo op.)