An online resource based on the award-winning nature guide

December

Hairy and Downy Woodpecker Bills

12-31-13 woodpecker billsDistinguishing Hairy Woodpeckers (Picoides villosus) from their smaller relatives, Downy Woodpeckers (Picoides pubescens), can be challenging if you don’t have a chance to view both species at the same time. The easiest way to tell them apart is to note the relative size of their bills. The Hairy Woodpecker’s bill is proportionately much larger than the Downy Woodpecker’s – it’s almost as long as its head — whereas the Downy Woodpecker’s bill is not nearly as impressive. Although a Downy Woodpecker can’t drill or probe as deeply into trees as a Hairy Woodpecker, it does have at least one advantage due to its overall smaller size; it is light enough to balance on the stems of goldenrods, which usually aren’t strong enough to support Hairy Woodpeckers. It is here that Downy Woodpeckers drill for overwintering goldenrod fly larvae inside goldenrod ball galls – a popular winter snack for this species.

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Black Bears Still Active

12-27-13  black bear tracks by GinnyFinding Black Bear tracks in late December shouldn’t come as a surprise, but it often does if you’re unaware of the true timing of hibernation. Most of us assume Black Bears are fast asleep by November, but entrance into hibernation is usually considerably later than this. According to Ben Kilham, a New Hampshire bear biologist , pregnant female black bears den first, around the middle of December, followed by unbred females in late December. Males stay active as long as there is a supply of food available and the weather isn’t too severe. Young males remaining active the longest, often into January, in order to put on as much weight as possible in order to compete with older males the following spring. Occasionally when a winter is particularly mild, and it’s a good year for mast crops such as acorns or beechnuts, you hear or see signs of Black Bear through the winter, but this is the exception rather than the rule. (Photo by Ginny Barlow – Black Bear hind foot on left, front foot on right.)

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Northern Hawk Owl

n. hawk owl3- 231The Northern Hawk Owl is a bird of the remote Alaskan and Canadian boreal forests. Its name reflects the fact that this diurnal owl has both the appearance and behavior of a hawk, specifically, an accipiter. Although the Northern Hawk Owl winters throughout its breeding range, it periodically erupts southward into southern Canada and the northern United States. Sightings of this bird are rare in Vermont, but in recent winters, including the current one, there have been some. As with Snowy Owls, the magnitude and extent of these winter irruptions are thought to correlate with high reproductive success followed by severe winter conditions and decreased prey availability, but much remains to be understood about their winter dispersal habits. What we do know is that the Northern Hawk Owl’s skills as a hunter are very impressive. It can detect prey (small rodents, grouse, hares) by sight at a distance of half a mile and just using its ears can find prey under a foot of snow.

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Pileated Woodpecker Sign

12-26-13 pileated sign2 IMG_8246Pileated Woodpeckers typically make rectangular holes in trees in order to reach the carpenter ants that live in galleries they’ve created deep within a tree. While ants are high on a Pileated Woodpecker’s list of preferred food, wood-boring beetle larvae are not far behind. Sometimes the exertion of jackhammering isn’t necessary in order to reach insect larvae – removal of the outer bark is enough to expose tasty morsels.

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Weasel Tracks

12-24-13 weasel & stonewall IMG_9602When looking for signs of weasel– Long-tailed or Ermine (formerly called Short-tailed Weasel) – in winter, stonewalls are a good place to head. Both of these nocturnal mustelids prey on small rodents such as mice and voles, which frequent the nooks and crannies of stonewalls. In winter weasels cover a lot of ground looking for prey – the home range of an Ermine is between 30 and 40 square acres, but when food is scarce, they may travel two or three miles in one night. Often their tracks will run the length of a stonewall on one side and then back the other side. Intermittent pauses are made as the Ermine stands on its hind feet and stretches its neck out, searching the landscape for both movement and sound.

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Snowflea Air Bags

12-23-13 snowflea IMG_0947Snowfleas are such remarkable little arthropods that they merit at least an annual post. The recent warm weather brought them up out of the leaf litter to the surface of the snow, where they constantly hurl themselves from one spot to another. If you don’t mind getting your knees wet, you can watch as snowfleas tuck their head down and catapult themselves through the air. Just before launching themselves, the snowflea everts three anal sacs from its anus. When the snowflea lands, these sticky appendages act like automobile air bags, absorbing the shock of landing as well as preventing the snowflea from bouncing around. There may be another function that they perform, but it is not known at this time what that might be. While there are many genera of snowfleas, only species in the genus Hypogastrura possess anal sacs.

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American Yew Female Cones

12-20-13  American Yew female cones IMG_6118Being a gymnosperm (its seeds are not enclosed in an ovary), American Yew, Taxus canadensis, lacks true flowers or fruits and possesses separate male and female (seed) cones. Each male cone produces up to 100 pollen sacs or more. The modified female cones do not resemble the typical woody cones of evergreens. Yews are the only conifers that produce seed cones that consist of a fleshy (and mucilaginous), scarlet, cup-shaped structure called an aril, each of which holds one seed. The seeds (not the aril) are poisonous to humans, but thrushes, waxwings and other birds consume them and aid in their dispersal.

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Porcupine Feeding Technique

12-18-13  porcupine incisor marks IMG_0150In the winter, the bulk of a porcupine’s diet is the inner bark, or cambium, of trees. The porcupine removes the outer bark (unless the tree is young or has thin outer bark and then it eats the outer bark as well) in order to reach the cambium layer, which lies directly beneath the outer bark. At this point the exposed surface is very smooth, more finely finished than the work of a beaver. Then the porcupine removes the cambium in small, triangular patches, each patch composed of five or six scrapes converging at one point, like sticks in a tepee. The point where the scrapes meet is where the upper incisors are placed and held fixed against the tree. The lower incisors scrape, making a fresh path with each scrape, as the lower jaw swivels in a narrow arc.

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Interpreting a Kill Site

12-18-13 hawk kill IMG_4136When there’s snow on the ground and you come upon a site where a predator successfully caught prey, there are usually signs that will help you determine who the main players were. In the above scene, remnants of red squirrel fur confirm the identity of the prey. If you look at the top of the image, you can make out a faint wing impression. Although not in this case, both wings of an avian predator often touch the surface of the snow, allowing you to measure the wingspread, and this information can help to eliminate some species of raptors. Birds of prey often defecate at a kill site. In the lower left corner of the photograph, as well as to the left and right of the packed area where the squirrel was eaten, you can see white (uric acid) bird droppings. Given that it is a hawk or an owl, knowledge about their respective evacuation habits will allow you to narrow down the possibilities even further. Owls tend to let their droppings do just that – drop, leaving small plops on the ground. Hawks, on the other hand, tend to forcefully eject their droppings some distance away. The long, thin streaks at this site were definitely propelled outwards, making it likely that the predator was a hawk. Familiarity with the hawks that overwinter in your area can help pinpoint which species it could be.

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Canada Lynx “Snowshoes”

12-16-13 lynx & bobcat feet IMG_3811Bobcats and Canada Lynx are in the same genus, and are roughly the same size (averaging 15 to 35 pounds), with Bobcats usually weighing a bit more than Lynx. The size of their feet is vastly different, however, and not proportional to their relative weights. A Lynx has much larger feet and longer legs than a Bobcat. Its range extends further north, which means it must be well equipped to deal with snow much of the year. A Lynx has big, furry paws, and when its feet land the toes spread way out. Both of these adaptations help a Lynx’s feet act like snowshoes, helping it to chase down food in the winter. Much of the time, this food consists of Snowshoe Hares –anywhere from 60 to 90 percent of the diet of Lynx is made up of hares. The soles of Snowshoe Hare feet are also well-furred, particularly in winter, enabling them to run on soft, deep snow without sinking in very far. Because Snowshoe Hares are extremely fast and agile (reaching speeds of 30 mph and jumping 12 feet in a single bound), the feet of any serious predator must also be well adapted to traveling on snow.

Note: Bobcat sightings are much more frequent than Lynx in northern New England (the southern tip of the Lynx’s range) but breeding populations of Lynx have been documented in the last two years in the boreal forests of Maine, New Hampshire and Vermont.

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Leafy Liverworts

12-12-13 Frullaria 008Plants that have no conductive (vascular) tissue are referred to as bryophytes. They include mosses, hornworts and liverworts, all of which reproduce with spores and do not form flowers or seeds. Liverworts are common in the tropics, but certain species are plentiful in New England. They are divided into two groups: flat, leafless thallus liverworts and leafy liverworts, which typically resemble flattened moss. You can easily confuse leafy liverworts with mosses but there are microscopic differences between the two. If you examine them under a microscope, you will find that leafy liverworts have leaves that are arranged in two or three rows while the leaves in mosses are spirally arranged. Liverworts of the Frullania genus, such as the liverwort pictured in this post, are classified as leafy liverworts. They typically have a reddish-brown color and attach themselves to a tree or other plant, obtaining moisture and nutrients from the air.

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Tracks Reveal Spotted Salamander Defense Mechanism

12-11-13  spotted salamander & fox tracks3 007Red Foxes have a very diverse diet – birds, small mammals, snakes, frogs, eggs, insects, fish, earthworms, berries, fruit — the list is endless and this diversity is part of the reason that foxes thrive in almost any habitat. However, the fox whose tracks I was following recently passed up a meaty meal – that of a Spotted Salamander. The story the tracks tell suggests that the fox dropped the salamander after unearthing it from its hibernaculum and carrying it some distance. It’s likely that it had detected the sticky white toxic liquid that Spotted Salamanders secrete from poison glands in their skin when they are threatened. Unfortunately, detection did not occur in time to save the salamander’s life. Either its experience with the fox and/or freezing temperatures killed the salamander, preventing it from going back into hibernation. (Note red fox tracks to right of salamander.)

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Bird Tracks & Gaits

12-11-13 bird tracks2 041Just a dusting of snow can reveal the patterns of tracks that different birds leave, and that pattern tells you how a bird moves (walks/hops). Frequently this knowledge can narrow down the possible species that made the tracks. In general, smaller birds tend to hop and larger birds frequently walk. This may be a result of conserving energy — short-legged birds move farther in a single hop than they do taking several steps, whereas it is more economical for larger birds, with longer strides, to move one leg at a time. In addition, birds that spend time on the ground foraging for food are more apt to walk, placing one foot in front of the other, much as humans do. Mourning doves, ducks, pigeons, and wild turkeys all leave “chains” of tracks, alternating feet as they walk. Birds that live mostly in trees and bushes tend to hop from one spot to another, even when they are on the ground, leaving paired tracks. Sparrows, including juncos, as well as finches frequently move in this way. There’s no hard and set rule, as some birds do both –American robins, ravens, crows and blackbirds are as likely to walk as they are to hop! (Photo shows tracks of Mourning Dove on bottom walking towards the left; Dark-eyed Junco above, hopping towards the right.)

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Praying Mantis Egg Case

12-9-13 praying mantis egg case 057In the fall, after mating, the female praying mantis lays up to 400 eggs in a frothy liquid produced by glands in her abdomen. This one to two-inch long mass is attached to vegetation, often grasses and goldenrod stalks, about a foot or two off the ground. The frothy structure hardens, providing a protective case for the eggs. In the spring, miniature (wingless) mantises, called nymphs, will hatch from this egg case. When hatching, the nymphs appear all at once, crawling from between tiny flaps in the case and then hanging from silk threads about two inches below the case. Within an hour or two, after drying out, they disappear into nearby vegetation.

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Warmer Winters Threaten Hibernating & Torpid Mammals

12-6-13 eastern chipmunk IMG_2845Winter air temperatures have increased in the Northeast during the past 100 years. A study by Craig Frank of Fordham University has found that as winter temperatures heat up because of global warming, chipmunks in areas that have experienced warmer winters become less likely to hibernate in the coldest months. The research indicates that chipmunks that follow normal hibernation procedures enjoy a survival rate through winter of about 87 percent, while those that remain active because of warm winter weather are almost certain to die by spring (due to higher metabolism requiring more food). This finding could mean dire consequences for all mammals that hibernate or become dormant during winter months, as exceptionally high winter temperatures correlate positively with reduced hibernation, resulting in a lower winter survival rate for these animals.

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Winter Visitors – American Tree Sparrows

You might guess from their name (both common and scientific) that American Tree Sparrows (Spizella arborea) inhabit wooded areas, but, in fact, you are much more likely to see them in small flocks on the ground in habitats more like their tundra breeding grounds — weedy fields, marshes and hedgerows. European settlers thought they resembled the Eurasian Tree Sparrow, and named them accordingly, but they are far different birds. They forage, feed and nest on the ground.
American Tree Sparrows do not breed in New England – they are strictly winter visitors and feed primarily on seeds and berries. They need to take in about 30 percent of their body weight in food and a similar percentage in water each day. Often they are observed scratching the ground for seeds, and occasionally beating their wings against grass seedheads in order to knock the grass seeds onto the ground where they quickly consume them. Look for American Tree Sparrows foraging beneath bird feeders during the winter months — come spring, they will disappear. (late edit: a photograph of a Swamp Sparrow accompanies this post. Although there is similarity in the appearance of Swamp Sparrows and American Tree Sparrows, this blogger should have taken more time when selecting the photograph for this post!)

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12-4-13  American Tree Sparrow IMG_9240


Blackberry Seed Gall

Galls, abnormal plants growths caused by many agents including insects, are formed during the growing season on the buds, leaves, roots and branches of plants as a response to chemicals or physical irritation. These galls serve as shelters and a source of food for their inhabitants. Blackberry is host to numerous gall-making insects, including mites, midges and gall wasps, and their temporary homes (galls) are more obvious now that Blackberries have lost their leaves. The Blackberry Seed Gall is caused by a cynipid gall wasp, Diastrophus cuscutaeformis. This wasp gets its species name from the resemblance of the galls it forms to the fruit of Dodder or Cuscuta, a parasitic plant. A cluster of small, globular, seed-like galls within which the gall wasp larvae live are pressed together in a lump surrounding the cane. Each of these 1/10th-inch diameter chambers bears a spine, and together they create a reddish-brown hairy mass.12-3-13 blackberry gall IMG_0555


Beaver Breath

12-2-13 beaver breath  074It’s very subtle, but in winter, especially when it is very cold outside, there is a way to tell if a beaver lodge is occupied. The temperature inside the lodge remains relatively stable at around 34 degrees Fahrenheit. When snow falls, it provides added insulation, raising the interior temperature of the lodge slightly. A layer of fat and thick fur keep beavers warmer than the air inside the lodge, plus they raise their body temperature even more by sleeping piled on top of one another. All the moist, warm air that beavers give off through breathing and evaporation escapes through the (mudless) vent that goes up through the center of the roof of the lodge to its apex. The vent’s purpose is the exchange of air; when the warm air inside the lodge rises and hits the cold air outside the lodge, it condenses and forms water vapor that is visible, indicating that there is life inside.

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Mink Slide

12-31-12  mink slide IMG_0004There is nothing like heading out on snowshoes to look for tracks after a major snow storm has passed. The pristine snow is often untouched, except for a few brave souls who have ventured out. Most of the mammals that are active in winter hunker down until well after it has stopped snowing, but the mink (Mustela vison) is not about to lose a night of hunting and its tracks can often be found the morning following a storm. Like other weasels, this bounding carnivore often leaves diagonally paired tracks, but unlike other weasels, its tracks are consistently the same distance (1 to 3 feet) apart. They also are most prevalent in or near wetlands. Although a fierce predator, the mink also has a playful side, much like its cousin, the river otter. Mink are known to dive under the snow and make short tunnels. Even more delightful to come upon are the slides that mink often make down inclines. If you see a groove in the snow about 3” in diameter, with paired tracks at either end, you have come upon such a slide.


Blueberry Stem Gall

12-20-12  blueberry stem gall IMG_7405If you happen to notice a ¾” to 1 ¼”- long, brown kidney-bean-shaped or round structure on a blueberry bush this time of year, you’ve come upon the blueberry stem gall – a summer and winter home for a dozen or so wasp larvae that will pupate and emerge in the spring as very small (less than 1/8”) black wasps (Hemadas nubilipennis). Last summer a female wasp laid her eggs in a tender, developing blueberry shoot. She then climbed to the tip of the shoot and stabbed it repeatedly, causing considerable damage. Within two weeks the eggs hatched, and the larvae began feeding, which, along with the egg-laying, stimulated the formation of the gall. Initially a blueberry stem gall is green and spongy; by fall it turns red, and by late autumn, it is brown and woody. Next summer, look for multiple holes in these galls that were chewed by the exiting wasps.


Fisher and Mink Tracks

1219-12 fisher and mink tracks IMG_2238As members of the weasel family (Mustelidae), fishers and mink have five toes on both front and back feet. Often all five digits do not register, but in prime tracking snow, you can often see them. Typically, mink tracks are found near a body of water, and fisher tracks are found under a canopy, not in the open. Where you have both water and trees, it’s possible to see signs of both animals. In general, the larger the animal, the larger its tracks. In this photograph, the mink tracks (smaller, in the middle) are heading towards the top of the photograph, and the fisher tracks (top most and bottom most) are heading towards the bottom of the photograph. Although not pictured here, both of these carnivores engage in snow sliding, much like their cousin, the river otter, and the resulting grooves are occasionally found when the snow is a bit deeper than it is now.


Spalted Wood

12-18-12 spalted bowl-maple,%20spalted%20bowl%204%20mike%20hawkins%201b%20s100%20q60%20web As an impressive number of people knew, the black markings on the yellow birch were caused by fungi that create what is called “spalting” in trees. When the temperature (70 – 90 degrees F.) and moisture content (30%) of certain trees (birch, beech and maple, most commonly) is just right, colonies of fungi infect them. There are different forms of spalting – the pictured fine black lines are referred to as “zone lines.” They are created when incompatible colonies of fungi come into contact with each other and lay down barriers to separate their territories. The presence of spalting indicates that the decay process has begun. Spalted wood’s natural beauty is highly regarded by wood turners and is held in contempt by the lumber industry (with time, the wood softens and weakens as it decomposes). As the Ohio Dept. of Natural Resources so eloquently states, “Spalted wood embodies all that is curious in the natural world. It is formed by unseen organisms at a specific time and place that only it knows.” (Thanks to John Gutowski for yesterday’s yellow birch mystery photo and the HobbitHouse for the bowl photograph.)


White-tailed Deer Population Estimation

12-14-12 deer scat IMG_6670White-tailed deer are known to eat over 600 species of plants in North America. They consume, on average, about 5 to 8 pounds of food for every 100 pounds of body weight, per day. As a result, a deer, on average, defecates about 13 times a day. A crude but somewhat accurate way to estimate how many white-tailed deer are in your area is to count the number of scat piles you find in a square mile within 24 hours, and divide this number by 13. A little snow on the ground would make this particular method of population estimation a lot easier!


Common Redpoll Irruption

12-13-12 common redpoll IMG_6802Common redpolls (Acanthis flammea), named for their red cap, are small northern finches that breed from the southern edge of the Arctic tundra down into the Canadian coniferous forests. Their size, shape, actions and voice are similar to those of goldfinches and pine siskins. The bulk of the common redpoll’s diet consists of the seeds of several different trees, including birches, alders and willows, as well as grass and weed seeds. While their winter range extends southward as far as Massachusetts, in winters when the seed crop of these trees is exceptionally poor, large numbers of redpolls come even further south into the U.S. seeking food, and these visits are referred to as irruptions. The numbers of redpolls at feeders throughout northern New England, as well as their presence in states further south confirm that the winter of 2012-2013 is such a year. Look for large flocks moving about in undulating flight over fields, alighting on weeds, as well as at and under feeders, where millet and sunflower seeds attract them. Between the redpolls’ brilliant red crowns and their constant twitter, they are hard to miss!


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