Amateur Naturalist: Tracking Through Snow

‘A’ points to a hoof mark and ‘B’ and ‘C’ point to grooves in opposite directions from hoof marks. Photo by Bob Walker

A male house finch all puffed up to keep warm. Photo by Bob Walker

By ROBERT DRYJA
Los Alamos

Snow has fallen quietly and straight down during the night. Trees have lines of snow along the upper sides of their branches in the morning. Pine trees have cups of snow in the clusters of their pine needles. The branches and needles absorb just enough heat from the sunlight to become warmer.

Snow melts. It falls to the ground throughout the morning, joining snow that already covers the ground. The result is a smooth layer, particularly in open areas that were open grasslands in the summer. This provides an ideal setting for a hiker to see what may have been walking around after a snowfall.

A jackpot of deer tracks is found during today’s hike across the snow. The tracks of three deer appear. They move in a line across an open area, heading toward some woods. They may have been grazing in the open area and then decided it would be more comfortable in the woods where less snow lay. One set of tracks has distinct hoof prints.

The other two sets of tracks in contrast are composed of grooves as well as hoof prints. The grooves are widest at the hoof mark but then narrow to a point going away from the mark. Two deer may have not raised their legs completely above the snow where it was several inches deep. The result are grooves where a leg was dragged across the top of the snow. One set of grooves points in one direction while the other set points in the other.

A different set of tracks appears further on. This time the prints are in pairs at a diagonal to one another, (See Picture 2). The pairs of prints are about a foot apart and the snow has collapsed a little around them. There is some uncertainty as to what kind of animal made them, but it probably is a rabbit. This is a result of eliminating other possibilities. Ideally one pair of prints would be smaller than the pair next to them. There then would be alternating pairs small and large prints. This would distinguish between the smaller front legs and larger back legs of a rabbit as it hopped across the snow.

Alternatives to a rabbit would be a squirrel, skunk or raccoon. However a squirrel has much smaller feet. Skunk or raccoon prints would be expected to show claw markings. Winter also is not the time for a raccoon or skunk to be wondering about.

The deer and rabbit trails lead toward some tall trees. A flock of red winged blackbirds have gathered and are making a tremendous racket at the top of one tree. Something that sounds like a shrill “conk-a-ree” is made repeatedly. They decide to fly away and erupt as a group from the tree branches, heading toward a more distant tree. Flocks of up to sixty birds have gathered from time to time in these trees during the winter.

Red winged blackbirds are associated with living near ponds, marshes and streams during the summer. They fly further afield in the winter. In this case they have flown to the woodlands at the lower elevations of the Jemez mountains. An annual pattern has been emerging. Previously none had been seen at any time of the year in this area. A flock then arrived in the late summer starting about ten years ago. They remained out of sight in a ponderosa tree but made their typical calls. A few could be seen if a person looked carefully through the branches toward the trunk. Flocks have become more common since then. They now are out in the open at the top of trees that have shed their autumn leaves. Two or three flocks may cluster near one another among trees.

Are red winged blackbirds coming as a result of the forest fires in 2000 and 2011? Large sections of the Jemez mountains have had dense woodlands replaced with grasslands and shrubbery that may be attractive to red winged black birds. Such are the thoughts that can occur while following animal tracks in the snow.

Another thought occurs when looking at house finches. They gather and remain in shrubbery closer to the ground, unlike the red winged blackbirds that prefer being higher in trees. House finches are small compared to the red winged blackbirds. A house finch weighs in the range of ¾ of an ounce while a red winged black bird weighs about 3 ounces. The temperature is approaching freezing during the hike. A house finch has a normal body temperature of 104 degrees. One the one hand a house finch needs to generate only enough body heat for the ¾ ounce of body weight.

On the other hand it cannot afford to lose much heat either. How does it keep from freezing when the temperature may drop below the freezing point at night and there also is a breeze? Feathers are the answer. The fur on mammals provide insulation but feathers are remarkable in comparison. About 15-20 percent of the weight of house finch is in its feathers. The percentage indicates the importance of feathers for a bird’s survival.

This means a little over 1/10 of an ounce of feathers insulates a house finch from the cold. (A 150- pound person in comparison would have 30 pounds of hair all over their body for 20 percent of their weight.) Although a relatively large percentage, it still is a small absolute number for weight. Feathers have a variety of shapes. Down is a type of small flexible feather close to the body of a bird with the primary function of insulating the body. Larger, contoured feathers grow away from the body and cover the down. A bird may fluff up its contour feathers when not flying. This results in the down feathers becoming more spread out and so providing more insulation. A house finch may appear twice as large as usual when it puffs its feathers.

A rabbit leaves prints in the snow. Photo by Bob Walker

A winter gathering of red winged blackbirds at the top of a tree. Photo by Bob Walker

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