Volume XXV - 1994

Winter at Crater Lake is a time of deep snow cover. Many animals avoid these difficult living conditions either by migrating or hibernating. Yet quite a few animal species found in the park remain active throughout the winter. Many of these animals spend at least some of their time on the surface of the snow, leaving tracks that are not easily observed in other seasons. In fact, winter is the best time to see evidence of some less commonly observed species such as pine martens, martes americana.

Where and When to Find Tracks

The abundance of wildlife here makes finding interesting tracks especially easy. Tracks can be found just about anywhere in the park, even in the sparse vegetation and harsh conditions on exposed peaks and ridges. Most people who visit Crater Lake in winter stop et Rim Village, where large numbers of pine marten and squirrel tracks can be seen. Park Headquarters, an area with less severe weather conditions and more diverse forest has a wider variety of tracks.

The best times to look for winter tracks are the first few days after snowstorms. During storms, animals are generally less active and any tracks will be quickly covered by new snow. The older a track is, the more likely it will be obscured or erased by drifting, melting, or drippings from trees. Some of the older windswept tracks may still be partly visible, however, as a raised pattern above the surrounding snow. These marks remain because the snow which had compressed to form the track is less susceptible to drifting.

Identifying Animals by Tracks

Almost all animal tracks have distinguishing characteristics which allow identification of their maker. Some of these tell-tale features are: appearance of individual prints (size, shape, presence of claws, number of toes), distance between sets of prints, distance between left and right feet, and the general pattern of the track. The appearance of a single print is the least useful means of identifying tracks because the clarity of a print varies depending on the snow conditions, the age of the print, the typical walking gait of the animal, and what the animal was doing when it left the print. The most useful pieces of information for identifying an animal by its track are the general pattern of the track, determined by the animal's gait and the spacing of the prints. In snow, even weathered tracks usually provide this much information.

Animal tracks are easily divided into three groupings. The groups are: an alternating track, the two-print bound, and the four-print bound. These divisions usually relate more to the appearance of the track pattern rather than the animal's gait. Most animals have some variations in their track patterns, but if the track is followed any distance, it will usually revert to one of the main groups.

The alternating track, common to all dogs and cats, is generally made with a walking or trotting gait. It is characterized by legs moving diagonally together, with the hind feet placed in or near the prints of the front feet. An alternating track can also result from side to side stepping, such as in the porcupine's waddle.

The two-print bound is most commonly seen in members of the weasel family. It occurs when the animal leaps and lands on the two front feet, then lifts the front feet for the next bound as the rear feet land in the prints of the front feet.

The four-print bound is a signature of the common rabbit hop. This pattern is created when the front feet land first after the leap, followed by the hind feet landing on the outside and ahead of the front feet.

These three groups encompass tracks from very small animals, such as mice, to the largest mammals active in winter. To narrow the animal identification, two measurements are useful. One is the straddle of the track, which measures the width of the track between the outside edges of the prints. The other is stride, or the distance from one foot print in a track to the next print made by the same foot (diagram b). A ruler or any object (such as a knife or a ski pole) can be used for measurement.

If snow conditions are conducive, the footprint itself can be very instructive. The three main distinctions in prints are: presence or absence of claws, number and spacing of toes, and dimensions of the print. Persistence in following a back can often lead to finding a clear print.

In addition to characteristics of track pattern and print, the habitat where a track was made can help identify a track. At high mountain settings like the park, many animals are only present in certain elevation ranges. Similar looking tracks, such as pine marten and mink, mustela vison, can be distinguished in part by their location -- such as running between trees (pine marten) or to and from streams (mink).

The chart offers a summary of tracks and some of their characteristics for animals active in winter at Crater Lake. This is, of course, simplified as there are a number of books available on animal tracks and behavior for more comprehensive study.

Be aware that other phenomena can produce track-like patterns in the snow: drippings from trees, small amounts of snow rolling down steep slopes, wind drifts. Being alert to unusual tracks, such as those made by bird feet or wing beats, can also add to an outing.

For those enjoying the backcountry at Crater Lake National Park in winter, or on a quick visit to the Rim Village area, the ever-present snow cover can reveal the often missed world of animal movement and behavior. Tracking yields the same excitement as solving a good mystery, with the added benefits of outdoor exercise and education. Tracking may even provide valuable information on rare or endangered species which often go unseen in the park.

Animal	Track group	Avg. straddle Avg. stride	Where found
Common Tracks
Pine Marten	2-print bound	3-4.5" 24"	Throughout park
Douglas Squirrel	4-print bound	2.5-3.5" 19"	All park forests
Deer Mouse	4-print bound	1.4-1.8" 3.7"	Throughout park
Bushtail Woodrat	4-print bound	2.3-2.7" 11"	Rock slides, pines, buildings
Snowshoe Hare	4-print bound	6-8" 32"	All park forests
Long-tailed Weasel	2-print bound	1.8-2.8" 20"	Throughout park, may be near water
Less Common Tracks
Coyote	alternating	4-7" 18"	Throughout park
Mink	2-print bound	2.3-3.5" 22"	Near creeks
Porcupine	alternating	5.5-9" 7"	Throughout park
Rare Tracks
Bobcat	alternating	5-7" 12"	Low elevations
Short-tailed Weasel	2-print bound	1.1-1.7" 14"	Throughout park
Nutall's Cottontail	4-print bound	4-5" 24"	Ponderosa pine forests
Northern Water Shrew	4-print bound	0.9-1.1" 3.5"	Near streams
Meadow Vole	2-print bound	1.3-2" 6.5"	High mountain open areas

Further Information

Tom Brown, Jr. and Morgan Brandt, Tom Brown's Field Guide to Nature Observation and Tracking, New York: Berkeley Books, 1983.

Louise R. Forrest, Field Guide to Tracking Animals in Snow, Harrisburg, PA: Stackpole Books, 1988.

James Halfpenny, A Field Guide to Mammal Tracking in North America, Boulder, CO: Johnson Books, 1986.

Donald W. Stokes, A Guide to Nature in Winter, Boston: Little, Brown and Company, 1976.

Donald and Lillian Stokes, Animal Tracking and Behavior, Boston: Little, Brown and Company, 1986.