Chattering red squirrels also known as pine squirrels

When walking through the woods the silence is often pierced by the rapid chatter of a red squirrel as I intrude upon its territory. But the recent deep blanket of snow has the little red squirrel snug inside its nest. 

Red squirrels loudly scold any intruder in their territory

Red squirrels will sleep in tree cavities, abandoned bird nests, under rotten logs or, most commonly, in dreys. Dreys are nests squirrels build out of leaves, sticks, grass or needles. They are spherical in shape with an inner chamber four to six inches across. A drey can be distinguished from a bird’s nest because of the presence of dried leaves and its spherical shape. 

A drey that has fallen out of a tree and broke into two pieces

The inside of the chamber is lined with soft material, such as shredded bark, bird feathers, animal fur or dried grass. Squirrels will keep adding material to the outside of the nest to insulate and waterproof it. 

With a few inches of material separating the inner chamber from the outside air, the temperature on the inside of the nest is several degrees higher than on the outside. To increase the insulating factor, squirrels often construct the dreys on the south side of a tree to maximize the warmth of the sun. 

Often a squirrel will build the drey high in a tree above one of it’s middens, of which the squirrel can have as many as six middens. A midden is the squirrel’s cache of cones that it eats during winter when other food is scarce. 

Red squirrels often eat cones on top of their midden, adding to the pile

These middens and the associated cone trees make red squirrels one of the most territorial animals in the forest. Their chatter, screams, growls and screeching make their territory well known to intruders. 

Squirrels will also mark their territory by leaving their scent along frequently used paths. Glands in their cheeks leave a scent when rubbed against an object. 

Once snow covers the ground, squirrel trails become obvious--a tiny packed trail between trees. If the snow is deep, the tracks may disappear at the tree trunk and delve beneath the snow to a midden or up the tree to a drey.

Unlike other small rodents, most red squirrels nest above the snow high in a tree, whereas mice and voles spend the winter in the subnivean space beneath the snowpack. The temperature is more moderate between the ground and the snow, making winter easier to survive for those rodents.

Not so for the little red squirrel. During inclement weather, a squirrel will hole up in its drey, lowering its rate of energy expenditure. With a cache of cones nearby and the capability to obtain dietary moisture from its food, the squirrel doesn’t have to travel far in the winter. 

A well-defined squirrel trail led to this squirrel's midden

But when the squirrel does travel in the warmer months to harvest food and feast on berries, fungi, buds, and seeds, its stays within its home range. Depending on the abundance of food, their home range can range from 0.7 acres to 3.7 acres.

Any intruder into a squirrel’s home range will receive a long scolding if he comes too close to a midden, breaking any silence that might have been. 

Note: Published in the Bonners Ferry Herald on Dec. 27, 2012. 

Only cartoon turtles can remove their shell

Burrowed in mud at the bottom of a pond are turtles waiting out winter. Come spring, they will be basking on logs and rocks soaking in the sun’s rays. Since the painted turtle is the only native turtle in Idaho, it is easy to identify. But in other regions of the country, more than one turtle species exists.

Painted turtle basking in spring sun

When identifying a turtle, the shell is often the defining characteristic. Turtle shells are commonly brown, black, or olive green but can have red, orange, yellow or gray markings that help in identification. 

The shape of a turtle’s shell indicates its lifestyle. Aquatic turtles, such as the painted turtle, have flatter, streamlined shells that let them glide through the water easier. Land dwelling turtles typically have high-domed shells to protect them from the jaws of their predators.

Streamlined shells help painted turtles swim more efficiently

Some turtles can pull into their shells to evade predators, but unlike cartoons, they cannot remove themselves from their shell. A turtle’s shell isn’t like a snail’s shell that is completely on the outside, instead a turtle’s shell is part of its skeleton, much like people.

The shell is composed of two sections: the carapace (the top half) and the plastron (the bottom half). A bony bridge fastens the two sections together. Both the carapace and the plastron are made of bone and scutes. The carapace consists of 50 to 60 rib and back bones while the plastron is a fusion of the clavicle and rib bones. The bones are flattened into plates that fuse together.

Scutes form designs on a turtle's shell specific to each species 

The bone contains a blood and nerve supply and is protected by scutes. The scutes are overlapping pieces of keratin, the same material in other reptile scales and our fingernails. Even though the scutes provide protection, a turtle can still feel pain and pressure through its shell. 

Turtles are capable of repairing damage to their shell if it isn’t too extensive--like being run over by a car. The blood vessels in the bone provide protein and calcium for the bone to regrow and reshape itself. 

Most turtles have approximately 38 scutes protecting the carapace and 12 to 14 scutes on the plastron. A turtle has the same number of scutes throughout its life. Since the shell is part of the turtle’s skeleton, it grows with the turtle. Just as a baby’s skull plates are not fused at birth, a baby turtle’s bone plates don’t fuse together until it has grown to its maximum size. 

As the bone plates grow, the scutes also have to grow to cover the bone. Some turtles, such as wood turtles, enlarge the diameter of the scutes by adding layers of keratin which creates “growth rings”. 

Unlike trees, the growth rings are not completely reliable for determining age because more than one ring can grow a year and older rings can be worn down and be hard to distinguish. 

Other turtles shed the old, smaller scutes as they are replaced by larger ones from underneath. The old scutes often fall off while basking in the sun on a warm summer day because the sun’s warmth dries out the old scutes while also warming the cold-blooded turtle. 

Note: Published in the Bonners Ferry Herald on Dec. 20, 2012. 

Conks begin recycling trees before they’re dead

High in a birch tree, a large conk grows on the trunk--a sure sign the birch is decaying from the inside out. Conks, also known as shelf fungi or bracket fungi, are an external indicator that a tree may be rotten inside. 

Bacteria and fungi both can cause decay, but fungi are more obvious, especially conks. While conks grow in a variety of shapes and colors, most assume a shelf or bracket shape with a woody or leathery top. 

Named because of their shape, shelf or bracket fungi are also called conks

The conk visible on a tree trunk is only a small portion of the entire fungus. Actually, the conk is the reproductive part of the fungus, roughly comparable to a flower or cone. 

What is not visible is the main body of the conk which is composed of slender filaments that are collectively called mycelium. The filaments, called hyphae, penetrate the substrate in which they grow, in this case wood, to absorb nutrients. 

Fungi have to obtain food by absorption because they lack roots, stems, leaves and chlorophyll, which is why they are a fungus and not a plant. 

As the mycelium absorbs nutrients in the wood, it decomposes the wood in the process. Therefore, shelf fungi are considered a major wood rotting fungus that cannot be killed once a tree is infected.

The rot caused by conks attacks the top of the tree, the heartwood inside and the base of the stem. Conks can either cause brown rot or white rot. 

Brown rot makes the wood dry, brittle and darker than the original wood. This is because the fungus cannot break down the lignin in the cell walls. Lignin is a reddish-brown molecule that makes the cells stronger and waterproof. 

On the other hand, white rot makes the wood soft, spongy and whiter than the original wood. While white rot attacks both the lignin and cellulose (the molecules in paper), the rotted wood is white because the fungus leaves the cellulose behind. 

Only after several years of decay by the mycelium does a conk form. Unlike familiar mushrooms that produce new reproductive parts every year (such as morels), a conk builds upon itself every year by adding a new layer. Each layer has pores on the underside of the ‘shelf’ that are vertically orientated. If a tree leans as it decays, the conk will grow new pores that are vertical the next year.

A second conk grows out of an older conk to keep the pores vertical

Vertical pores are important because the spores produced within the pores have to drop down the pore into the air without sticking to the sides. These spores then travel via air currents and ideally find a tree to establish itself in. 

Since the chance of landing in an ideal location is slim, conks compensate by producing an abundance of spores. A large conk can release 30 billion spores a day for a period of six months--that’s five trillion spores released annually. 

These spores can establish themselves on growing trees, fallen trees on the forest floor or any tree that is moist. 

Without fungi, the forest floor would be littered with trees from hundreds of years because fungi are important recyclers. Fungi break down woody debris through rot which recycles nutrients back into the soil. The nutrient-rich soil then supports the growth of a tree in which a shelf fungus will establish itself someday. 

Note: Published in the Bonners Ferry Herald on Dec. 13, 2012. 

Mountains moved to form the Purcell Trench

The Kootenai Valley and the Selkirk, Purcell and Cabinet Mountains are the main geographic features in Boundary County. One geologic feature is responsible for how we see them today--the Purcell Trench. 

The Purcell Trench is the valley structure between the Selkirk Mountains and the Cabinet and Purcell Mountains. The Purcell Trench extends beyond Boundary County. The southern edge is in Rathdrum Prairie, though south of Sandpoint it is harder to distinguish. The Purcell Trench also extends north into British Columbia where it eventually merges with the Rocky Mountain Trench.

From atop Clifty Mountain (in the Cabinets), the Purcell Trench is visible into Canada

Valleys can be made by erosion (water or glaciers) or by an underlying geologic structure. The Purcell Trench is too long, wide and straight to have been formed by erosion and, therefore, it is a result of a major bedrock structure. 

One bedrock structure responsible for creating valleys is a fault. The basin and range mountains in Nevada formed because of faulting. A fault is a fracture in rock where sliding occurs (both sides don’t have to move, often it is one piece moving against the other stationary side). The San Andreas fault in California is one example. 

There has to be a reason for rock to move and in the case of the Purcell Trench  it was because this area was being stretched. As one can imagine, rock isn’t a likely candidate for stretching, so what happens is faulting. Faulting releases the tension built up by stretching. 

Purcell Trench south as viewed from Tungsten Mountain in the Purcells

What caused the stretching? Intruding magma. Long before the ice ages, a large mass of granitic magma was rising in the Earth’s crust under the present day Selkirk Mountains. As the giant bubble of magma neared the surface, it weakened the crust by stretching it. 

The giant bubble of granitic magma cooled before it reached the surface, creating a giant granite batholith. But the tension was still there from the stretching. 

Consider that the granite cooled miles below the surface and now is exposed in the Selkirk Mountains. Something had to move to make the granite visible, it wasn’t initially eroded away. 

Exposed granite in the Selkirks cooled several miles below the earth's surface

Quite a bit of imagination is necessary to envision what happened. The rock that is now the Cabinet and Purcell Mountains was once on top of where the Selkirk Mountains are located. When the magma intruded, it bulged up the overlying rock, much like a bubble forming in pizza crust. To release the tension, a fault formed along the current eastern front of the Selkirk Mountains. Over millions of years the rock on top (the current Purcell and Cabinet Mountains) slowly slid down the fault in an easterly direction into their current position, leaving an open trench behind. That open trench is now called the Purcell Trench.

Looking east across the Purcell Trench at the Purcell Mountains

As the overlying rock slide off to the east, the granite batholith was exposed. 

The rocks around the fault zone are under tremendous pressure as the faulting occurs, which results in folding and metamorphosing the rocks. Rocks along the eastern front of the Selkirk Mountains may have a shiny look to them, with all the crystals aligned in one direction--these rocks were altered by the heat and pressure in the fault zone. 

Have you taken a close look at the rock cut where the Myrtle Creek Road takes off from the West Side Road? This rock was folded deep in the crust along the fault zone as the Purcell Trench was being formed. 

Sediment has filled the Purcell Trench (looking west at the Selkirk Mountains)

The Purcell Trench doesn’t look the same today as it did after it was initially created. Glaciers, lakes and rivers have scoured, eroded and deposited sediment to create the valley we know today as the Kootenai Valley.

Note: Published in the Bonners Ferry Herald on Dec. 6, 2012.