Site Inspection

Module 4      Site Inspection

A thorough site inspection is the foundation of effective wildlife damage management (WDM)  because you cannot control what you have not correctly identified. This module discusses how to perform a site inspection as well as the skills and equipment needed.

Learning Objectives

  1. Describe the inspection process.
  2. List the proper tools needed to do the job.
  3. Explain when to use the tools.
  4. List the questions to ask to obtain needed information.


Take the time to determine the nature of the problem. Even if you cannot conclusively determine the cause, a site inspection will help narrow down the list of suspect animals.

Through the inspection, try to answer these three questions:

  1. What is the nature and validity of the problem?
  2. How can the problem be resolved?
  3. What potential problems can be prevented?

Requirements for an Effective Inspection

Effective site inspections require coordination of three elements: persistence, knowledge, and equipment. Weakness in any area will result in less than adequate inspections.


Wildlife damage inspections put a strain on you and your equipment. For example, you have to put up with weather conditions, such as summer heat and winter cold, snow, and ice. It takes time to conduct a thorough inspection, so plan accordingly.


For effective WDM, you need to know about animals, their biology and habits, and the damage they cause. With each inspection, you will gather more experience reading the clues at the site.


  1. Quality flashlights are needed to inspect areas hidden in the shadows or at night.
  2. Protective equipment, such as gloves, knee pads, and goggles will reduce the chance of injury.
  3. Magnifying glasses (5x or 10x) and binoculars (8-power with a 30° field of vision or greater) improve visual inspection.
  4. Multi-purpose tools such as a Leatherman™ are useful for pulling apart scat and measuring scat and tracks.
  5. Digital cameras (or smart phone cameras) with a minimum of 3 megapixels that are small enough to fit in a shirt pocket (Figure 1) are important for documenting inspections and sending photos out for expert opinion.
  6. A notebook is essential to record findings. Don’t rely on your memory.
4_1 Pocket sized camera
Figure 1. Pocket-sized digital camera. Photo by Stephen M. Vantassel.

Inspection Process

Inspection is a process, not an event. Discipline yourself to go through the entire inspection process every time. Develop a methodical way to check for evidence of wildlife access or damage.


You must gain an understanding of the common wildlife species in your area. Start by developing a list of animals that often have conflicts with humans. Your list should include about 20 species or species groups. Next, read about the biology, diet, and behavior of the species on your list, as they will be primary suspects when you discuss the wildlife conflict a person is experiencing.

Learn the behavior of the animals in your geographic area. The inspection process is all about ruling out possible suspects. Consult the companion Species Information manual for insights into animal biology and the signs for the damage each species causes.


In our busy world, we encounter many distractions that prevent us from learning how to observe, or how to REALLY look at something. Critical observation, the kind necessary for WDM inspections, requires you to focus your eyes on a single spot at a time. Peripheral or broad vision simply is not focused enough. Narrow your focus to see how a branch was cut or how a track was placed. The effort may be tiring initially, but with practice it will become second nature.

Use the following test to ensure that you are able to focus properly. Take a newspaper and find a photo in it. Look at the photo closely. When you are able to distinguish the spots that make up the photo, you have focused carefully enough.

Step 1 – Pre-inspection

You must think like a detective and ask pointed questions to gather accurate information. Clients frequently change their stories and provide contradictory information. Your task is to tease out the accurate information. Here is a list of sample questions.

  1. What is the nature of the problem? Is it damage from browsing, clipping, gnawing, pecking, digging, or tunneling? Have the client provide specific details.
  2. Has the client seen the animal? Be careful here as sometimes the animal that is seen is blamed for damage done by other animals. Turkeys are a great example of this. They often get blamed for crop damage even though it was done by other animals.
  3. How long has the problem been occurring?
  4. How severe is the problem? Have the client quantify the extent of the damage.
  5. What time of day does the problem occur? Does the damage occur during the night, day, or at dusk or dawn?
  6. Has the client taken any actions to resolve the problem? What were those actions? Did those actions have any effect?

Step 2 – Site Visit

  1. As you approach the location, consider the neighborhood and the habitat it contains.
    1. Are wooded areas nearby?
    2. Is a stream or body of water nearby?
    3. Where would wildlife live and eat?
    4. Determine the location of the damage.

We emphasize the location of damage or sign because it is one of the best clues for identifying the cause of the problem.

Use the following questions to help narrow down your list of suspects.

  1. Is the damage below ground? Consider moles and voles.
  2. Is the damage at ground level? Consider beaver, chipmunks, raccoons, skunks, tree squirrels, voles, and woodchucks,
  3. Is the damage within one foot of the ground surface? Consider deer, rabbits, raccoons, and woodchucks.
  4. Is the damage occurring more than one foot off the ground? Consider birds, deer, tree squirrels, raccoons, opossums, and woodpeckers.

These terms will help you put a name to the sign you are seeing.

Disappearance – Plant item is removed without leaving any plant material behind.

Divot – A scrape or dug out portion of the soil where you can see the bottom of the depression (Figure 2).

4_2_Divot created by tree
Figure 2. Divot created by a tree squirrel. Photo by Stephen M. Vantassel.

Clipping – nibbling or biting the end of a stem or branch into short sections (typically less than 3 inches; Figure 3).

Figure 3. Branch clipped at a 45°-angle by a cottontail rabbit. Note the clean cut. Photo by Stephen M. Vantassel.
Figure 4. Groove in the grass created by voles. Photo by Stephen M. Vantassel.

Furrow or groove – linear depression in the soil or turf caused by animals repeatedly traveling or foraging on the same strip of land (Figure 4).


Gnawing – Animal biting or chewing on an object (Figure 5).

Figure 5. Gnawing of bark done by a cottontail rabbit. Photo by Stephen M. Vantassel.









Hole – If you can’t see the bottom of a depression in the soil, then it’s a hole (Fig. 6).

Figure 6. A hole dug by a 13-lined ground squirrel. Photo by Stephen M. Vantassel.

Run – The eruption of soil in a trail caused by a mole digging just below the surface. It collapses when depressed (Figure 7).

Figure 7. Runs created by moles, visible here because of dead grass. Photo by Stephen M. Vantassel.

Put it all together

Look for tracks or scat that might confirm the suspect animal. Don’t be surprised if you don’t find any. Tracks are difficult to find on compacted soils and asphalt. Scat isn’t always available or may be washed away by rain.

Ultimately, you have to put all the pieces together, and like a detective, rule out suspects and narrow down the list of likely candidates. In some cases, it isn’t necessary to determine the specific species. Even narrowing down the suspect to a type of animal (climbing, walking, or flying) may be enough to suggest a plan of action.

Take quality photographs

Sometimes you need another opinion to identify specific sign. The sign may be a track, scat, hole, or nibbled twig – any indication of the culprit. Photographs are an excellent way to have a colleague view what you are seeing. Here are a few tips.

  1. Set your camera at the highest resolution.
  2. Set your camera to macro mode when taking photos within 1 foot of the subject.
  3. Provide scale. Set a ruler or standard-sized object in the frame to show how large or small the sign is.
  4. Take wide-angle photos of the area to help the viewer see the context surrounding the sign.
  5. Position the sign between yourself and the sun so that the shadow provides the best contrast.

Inspecting Animal Damage to Structures
In addition to the damage wildlife inflict on the landscape, they may enter structures. Investigate the structure carefully for the location(s) where the animal(s) entered. Clients will want to discuss what they heard or smelled, but the size of the hole or entryway remains the most accurate way to identify the species entering the structure.

Holes can be identified easily by use of a powerful flashlight. Shine the light at the dark spot. If the spot remains dark, then the location is a hole (Figure 8a). If it is illuminated (Figure 8b), then the structure is reflecting light back to you and a hole is not present.


Figures 8a (top) and 8b (bottom). The dark spot in 8a remains a suspected entry point for bats until it is fully illuminated. In 8b, the light is reflecting off a board that blocks entry. Photos by Stephen M. Vantassel.

The following sizes are the smallest diameter openings required for the listed species to enter.

  • ¼ inch – house mice, some snakes
  • ⅜ inch – bats
  • ½ inch — small rats
  • 1 inch — rats, flying squirrels, red squirrels
  • 2 to 3 inches — fox squirrels, gray squirrels
  • 4 inches — raccoons, skunks, and opossums

When trying to determine if a hole is active, plug it with newspaper. Newspaper is easy for most animals to remove, except for bats and bees. If the paper is undisturbed for 5 days during good weather conditions, you can be reasonably certain the opening is no longer being used, assuming the animal doesn’t hibernate. Do not secure the hole unless there have been several days of good weather with warm temperatures. NEVER secure a hole unless you are certain it is no longer being used.

Mysterious Situations

Sometimes you will not be able to identify the source of the problem. Select from the following techniques that are most suitable for your situation.

  1. Set a cage trap with bait that is attractive to a wide range of species.
  2. Create a track trap (to capture tracks!) with sifted soil, flour, or talc. Flour is very effective when dealing with rats (they eat flour) but it can attract insects. Track traps must be protected from rain, wind, snow, or other elements.
  3. Plug a questionable opening with newspaper to determine if it is an active entryway.
  4. Install a trail camera capable of taking photos in the dark when a motion sensor is triggered.
  5. Ask neighbors to monitor the situation.

Questions for Reflection

  1. Explain the steps of the inspection process.
  1. How do you know if a dark spot is a hole?
  1. List the three tools you believe are the most important for performing an inspection and explain the reasons for your choices.
  1. Identify two techniques to use when you cannot figure out what species is causing a problem.
  1. Why is scale and resolution so important when taking photos of wildlife damage