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Ruffed Grouse

Ruffed Grouse Unable To Seek Refuge in Snow Caves

1-29-16 ruffed grouse bed 049

Unlike much of the Northeast, central Vermont has only a few inches of snow on the ground. These conditions can affect all forms of predators and prey both negatively and positively, from exposed mice and voles to easily-satiated hawks and owls. In the case of Ruffed Grouse, which seek shelter on cold winter nights by diving into the snow, less than 10 inches of snow can spell disaster. In their snow caves they are hidden from view and well insulated (where it rarely drops below 20°F.).  A lack of snow can be life-threatening for grouse if the temperature drops too low for too long. Unable to create a sheltered cavity in the snow,  Ruffed Grouse bed down on top of it, often close to the base of a tree where there may be some shelter from the wind. Fortunately, most nights have not been extremely cold thus far this winter.

After the grouse departs in the morning, you often find scat where it bedded down. Grouse scat comes in two forms, one a dry, fibrous cylindrical pellet with a white-wash of uric acid at one end, and the other a softer, darker brown plop. The vast majority of a grouse’s diet (buds, twigs, leaves, catkins) goes directly through its digestive system and forms the dry, courser scat. Finer (and more nutritious) material such as the cambium layer of woody plants enters the caeca, two specialized pouches, before passing through the large intestine. The caeca contain bacteria which break down cellulose and produce the more digested, and therefore more liquefied, scat (see foreground in photo).

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Ruffed Grouse Flying Into Windows

1-25-16 dead ruffed grouse by Eve BernhardThose of us who feed birds are well aware of the hazards that windows and glass doors present to birds. The latest research shows that roughly 988 million birds are killed each year in the United States from hitting windows. Migratory birds and songbirds are the most common victims, but Ruffed Grouse, especially in the fall and winter, are very apt to collide with glass windows. (This phenomenon is not the same as the aggressive behavior towards glass that a bird’s reflection can promote, especially by males during the breeding season.)

Many of the grouse victims are first-year birds. Often, inexperienced young grouse, frightened by a predator, crash into buildings, trees or windows in a so-called “crazy-flight.” Hard, transparent glass is not something grouse recognize as a barrier, due to the reflections it creates. There are a number of things one can do to reduce the chances of this happening. Netting, decals, window film and tape hanging from the top of the window can help. One of many creative new products available are window panes that have external patterns that birds can see from the outside, but that are invisible from the inside. On a national level, legislation and bird-friendly buildings are gaining traction. For more window crash-prevention ideas, go to http://www.birdwatchingdaily.com/featured-stories/15-products-that-prevent-windows-strikes/. (Photo by Eve Bernhard)

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The Short Life Span of Ruffed Grouse

1-8-16  fisher and grouse 177Ruffed grouse typically have a short life span; few live to be three years old. By mid-August about 60 percent of the grouse hatched that year are lost to predators, weather extremes, disease, accidents (such as flying into windows) and hunters. Less than half of the surviving young survive through the winter to have a chance to breed in the spring, and less than half of those that survive long enough to breed make it to a second mating season. The hazards for a ruffed grouse are many, with predation at the top of the list.

Birds of prey, especially the goshawk and great horned owl, take many grouse, but terrestrial hunters such as foxes, coyotes, bobcats and fishers also take advantage of this plentiful food source. Along with hares, porcupines, squirrels, mice and voles, grouse are one of the fisher’s preferred foods. A fisher managed to capture a ruffed grouse in the pictured scene, leaving only tracks and a few tell-tale feathers to tell the story.

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Common Polypody Spores Dispersing

10-27-15 rock polypody 057Common polypody (Polypodium virginianum), also called Rock Cap Fern, is a perennial plant found most often growing on rock surfaces usually in moist, shady woods. Being a fern, Common Polypody reproduces by spores. Structures that produce and contain spores (sporangia) are found on the undersides of the fertile frond leaflets. The sporangia form round clusters called sori. The sori of Common Polypody are orange-brown when mature and lack the protective covering (indusium) that some other fern species have. At this time of year, the mature spores are being dispersed by the wind.

The ability of Common Polypody to tolerate extreme desiccation (the leaves roll up when moisture isn’t as available, and resume their normal state when moist conditions return) means it is well adapted to the extreme moisture fluctuations of rock surfaces. Its evergreen fronds are consumed in the winter by Ruffed Grouse, Wild Turkey, and White-tailed Deer.

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Ruffed Grouse Make Do With Shallow Soft Snow Depth

snow cave 143There are about five or six inches of new powdery snow on top of an icy crust in parts of central Vermont now, with more to come soon. It is common knowledge that ten inches of snow are necessary for Ruffed Grouse to dive into and burrow under the snow in order to make an insulating nocturnal snow roost. With only five inches of snow, a grouse still seeks shelter, but somehow it knows not to dive into the snow from the air. Rather, it lands on the surface of the snow, and then walks along making a groove in the snow as it goes, until it decides to rest for the night.

Several such resting spots were apparent today at the base of trees — slight depressions fully exposed. The grouse that made the snow roost in this photograph shuffled through the snow and then scrunched down without breaking the surface of the snow where it settled for the night, so that it had an inch or two of snow over its body – hiding it from predators, if not providing much insulation. In the morning, after defecating, it departed, not bursting out of a snow bank as it would if there were a lot of snow, but instead lifting off in plain view, leaving faint wing prints on the surface of the snow.

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The Effects of An Icy Crust on Wildlife

1-19-15  ruffed grouse snow cave IMG_8590This winter has brought us several storms that have ended in rain and were followed by plummeting temperatures. Just a few inches down into the powdery snow on top of the ground there is a ¼”-thick crust, and if you dig down several more inches, there is a second layer of ice, roughly 1/8”-thick. When a thick, icy layer of crust forms, it can have a dramatic effect on the lives of wildlife both above and below it.

Some animals are relatively unaffected by the presence of a crust but many predators and prey are significantly helped or hindered by it. Ruffed grouse cannot seek overnight shelter from the bitter cold and/or predators by diving into a foot of soft snow and creating a snow cave (see photo). On the other hand, small rodents have a distinct advantage — mice and voles have several layers of ice between themselves and hungry coyotes, foxes and owls. Snowshoe hares lose the advantage they usually have on deep, soft snow — “snowshoes” that keep them on top of the snow when the bobcat or fisher chasing them has to flounder through it. Turkeys don’t have the strength to dig down through one thick crust, much less two or more, in order to reach hidden acorns. If a deer is being chased, its pointed hooves will break through the crust, slowing the deer down, whereas the crust may well support a lighter predator, allowing it to outrun the deer. Red squirrels have to work much harder to reach their cached winter cones and to create tunnels.

What is a mere inconvenience to us humans literally is costing as well as saving the lives of wildlife this winter.

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Sedge Seeds

1-6-15  sedge fruit in winter 057Over 500 species of sedges in the genus Carex are found in the U.S. – over half of the world’s total. The great majority of these perennial, grass-like plants grow in the moist soil of meadows, marshes and bogs, as well as in high altitudes. Sedges are often distinguished from grasses by their stem, which is typically triangular in cross-section (“sedges have edges”). The flowers of sedges, each surrounded by a bottle-shaped bract, or modified leaf called a perigynium, are clustered on spikelets. The tips of these bracts persist after the seeds have formed, giving the spikelets a prickly appearance.

Because of their wide availability, the seeds are eaten by many kinds of wildlife, especially birds. Wild Turkeys, American Woodcock, Northern Cardinals, Horned Larks, Snow Buntings, Lapland Longspurs, ducks, rails, sparrows, redpolls and finches relish them. In the Northeast, Carex seeds, along with insects, are the most regular items in the diet of Ruffed Grouse chicks. Moose also occasionally feed on sedge seeds. (Photo: Longhair or Bottlebrush Sedge, Carex comosa)

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