Field Guide to Animal Tracks and Scat of California. Lawrence Mark Elbroch
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Название: Field Guide to Animal Tracks and Scat of California
Автор: Lawrence Mark Elbroch
Издательство: Ingram
Жанр: Биология
Серия: California Natural History Guides
isbn: 9780520951648
isbn:
The tank tread made by a traveling Desert Tortoise in the dunes of the Mojave National Preserve in southern California.
BUILD A TRACKING BOX A tracking box can be any size, from a small transportable shoebox to an area large enough for a human to run through. Once the box is ready, fill it with “good” substrate. The easiest medium is play sand purchased at a local hardware store, but you can experiment with local soils as well. Once you have chosen your substrate, tamp or trowel the surface until it is smooth and firm.
Tracking boxes afford many activities for the beginner as well as the more seasoned observer. For instance, place your tracking box near bird feeders or where you know animals frequent. By providing a controlled substrate you can track in any season regardless of circumstances, even if you live in a place where seasonal weather or field conditions make tracking difficult. Once an animal has walked through your box, analyze the tracks as you would in the field. Photography, journaling, and track casts can all be used in conjunction with a tracking box.
The tracking box is also an excellent tool for recording the tracks of specific species. For example, capturing small mammals or live insects and running them across the substrate allows for focused analysis of elusive tracks. To further hone your skills, step beyond the sandbox and into the wild. Smooth out substrates along your daily routes, and monitor the movements of animals in your area.
A composite journal page created by Mike Kresky. Track journals are both educational and beautiful.
Tracke r's Tools: Noninvasive Monitoring
Jonah Evans, Mark Elbroch, Michael Kresky
One of the most attractive aspects of wildlife tracking is that it is noninvasive and provides a rich, detailed record of wildlife presence, habits, and behaviors without the necessity of seeing or handling them. Wildlife tracking provides us cost-effective research methods, and indirect signs allow both hunters and biologists to invest their time in the appropriate place at the appropriate time if they want to catch their quarry.
Below is a brief introduction to several complementary research methods that you might be interested in experimenting with. We highly recommend that you also read Noninvasive Survey Methods for Carnivores by Long et al. (2008), which provides both a more detailed description of all of the following methods and an introduction to the science behind their use in wildlife research and monitoring.
Track Casting
Making a cast is one of the time-honored ways of creating a permanent record of an animal track. Because of the ephemeral nature of tracks in the field, a track cast invites you to revisit tracks over and over again. The three-dimensional aspect of the cast allows for more in-depth analysis of foot morphology. Creating a track cast collection is a tangible way to increase your exposure to animal tracks when not in the field. Track casts are also great for teaching tracking in a classroom or workshop setting.
The simplest and most cost-effective medium to use is plaster of Paris. It pours easily and dries quickly in most weather conditions. Latex, dental mold, or paraffin are used less often but are also effective. The following tips are for making casts with plaster.?
The trail and burrowing mound made by a mole crab. Their trails are common at low tide in the intertidal zone.
MIXTURE In a suitable container (either a plastic cup or Ziploc bag), mix a ratio of about two parts plaster to one part water in a quantity to fill and cover your track. The consistency of the mixture is of greater importance than the exact ratio and should be thick like a milkshake. Thinner, more watery mixtures pick up better detail, but they are more fragile and may have a chalky consistency when dried. We would also recommend that you add the water slowly. You can always add more, but if you add too much, you must hope you have additional plaster in your pack to thicken your solution sufficiently to use.
POURING THE PLASTER Many tracks are delicate, and pouring plaster directly onto the track can damage them. It is a good idea to hold your mixing implement about an inch above the track to break the fall of the plaster, which will then gently fill the track. Once the plaster has been poured, it is a good idea to tap or shake the surface with your mixing implement to encourage any air bubbles to surface and break. This also helps move the plaster into the deepest cavities of the footprint, like the fine marks made by claws.
DRYING Well-mixed plaster on a hot day in the sun and on dry substrate can be dry enough for transport in less than 20 minutes. In cold, wet conditions it may take a few hours. The cast should be fully cured in 24 to 48 hours.
OTHER TIPS A barrier of some kind placed around the track to hold in the plaster can improve the appearance and thickness (strength) of the cast. You can easily make such barriers by cutting out strips from plastic containers of various sizes.
As soon as water is added to plaster, a chemical reaction occurs that releases a small amount of heat. This is problematic for snow conditions, because the plaster melts the snow and misshapes the cast. The solution is a product called SnowPrint Wax, which is a wax that can be sprayed into the track before pouring the plaster. This product prevents the snow from melting.
You may also come across a track preserved in silt mud or clay. You can carefully cut and lift out such a track and preserve it in a dry area. Unlike casting, this preservation technique provides a more pristine first generation of the track; even better, it is not subject to the variables of casting.
Whether you are casting or cutting a track out of substrate, be aware of your impact on the land. Also realize that casting is potentially messy and may involve toxic materials. Clear and concise procedures regarding setup and cleanup of casting are imperative.
Photography
Photographs are a quick way to record tracks and are an excellent tool for learning. Inexpensive digital point-and-shoot cameras are capable of taking decent-quality track photographs and can be carried in a shirt pocket. The drawback of a compact camera is the small sensor, which often equates to high noise levels in low-light situations (common when photographing tracks). High-quality digital single-lens reflex cameras can produce professional-quality images but are bulkier, more expensive, and require more experience and skill to use correctly. Regardless of which camera you choose to carry on your tracking expeditions, your photographs will become a powerful tool for learning and documenting your observations.
Cameras are also excellent tools for recording rare animals. Mark Elbroch snapped this photo with a cheap flip phone to record the tracks of a rare Wolverine atop Castle Peak in the northern Sierras.
Photographs allow you to analyze details that you may have overlooked in the field. By keeping your photos organized and labeled, you can compile a library of different species that you can revisit and СКАЧАТЬ