by
The CLAW Problems & Solutions Committee

Preserving Wildlife Tracks
Preserving wildlife tracks can be both exciting and informative. For the field biologist there may be an advantage in preserving for future study a clear record of wildlife tracks in a particular area. For the sports enthusiast or backpacker, who might make a hobby of tracking wild animals, it may be worthwhile to take home some souvenir tracks. When preserving tracks, you will also become more familiar with the characteristics of habitats in which animals live.
Under rare circumstances it may be possible to cut around the track with your knife and lift it out intact. This may be possible in the mud of a dried lake bottom where pronghorn or coyotes left footprints when the mud was just right for leaving a firm, sharp print. However, in most cases, plaster of paris is used to make track casts for "take home" souvenirs.

Materials
Strips of waxed cardboard (cut from milk carton) to make a collar 2 1/2 inches wide by 12 to 15 inches long
Plaster of paris purchased at hardware stores, drug stores, or hobby shops
A mixing stick
A jar for storing the plaster
Two tin cans (one for water and one for mixing)
Water
Paper clips

Making Track Casts
The method for making track casts is simple. First find a suitable track. The track should be deep enough to produce a solid cast and clear enough to reproduce. Remove all sticks and debris around the track. Make a circle around the print with the 2 1/2 inch?wide strip of cardboard; attach the ends with paper clips. Press the cardboard about 1/2 inch into the ground. The cardboard serves as an outer mold for the plaster. Pack some soil behind the cardboard for reinforcement.
Next, in the tin can mix the plaster of paris with water while stirring with a stick until the mixture is the consistency of cream or pancake batter. A very thick plaster paste begins to set almost immediately. A thinner mixture gives you more time. If the plaster is too thick so that it doesn't flow readily, it may dry too quickly and fail to reproduce some details of the feet. If too thin or watery, it will run all over the place, taking a long time to harden.

Now fill the track with the plaster, covering the inside mold to a depth of 1 inch below the top of the cardboard. When the plaster has been poured into the track, wait patiently for 10 minutes or more to allow it to set hard. It is not wise to attempt to pick up the cast too soon.

To pick up the cast after it is hard, cut around it with a knife, remove some dirt from under the edges all around the cast, then lift out the piece from a point well underneath the track. This cast is called a negative cast. Simply brush off the mud and dirt after the cast has had a day or more to harden.

For a positive cast (which can be made at home), form a waxed cardboard mold and fill with plaster of paris mixture to the top of the mold. Cover the negative cast with a film of grease, vegetable shortening, or petroleum jelly. As soon as the mixture begins to set up, take the greased negative cast and carefully make an impression on the hardening plaster mixture. This will have to be done before the plaster mixture gets too hard, or the plaster will crack from the pressure exerted from the negative cast. With a little practice you can determine the necessary consistency for creating a positive cast that is a duplicate of the original track.

Precautions
Take great care if the track is in dry, dusty ground or sand. It may not be possible to acquire a good cast under such conditions. When attempting a cast in such a case, pour the solution directly into the track, but from a point as close above the track as possible. It should not be dropped in with any force. Tracks in snow also are difficult to cast. Even a fairly cold plaster solution tends to melt the bottom of the track and it can be frustrating to find that the batter has poured right on through. To avoid this, make sure the mixture is as cold as possible by stirring some snow in while mixing.

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