How to make a footprint tunnel
Use a footprint tunnel to find out which mammals visit your garden during the night, or when you're not watching. This step-by-step guide takes you through the process of making a tunnel.
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Footprint tunnels are a really handy, and easy, way to discover which small animals are visiting your garden that you might not otherwise see – whether they are coming to your garden overnight whilst you’re sleeping, or visiting when you’re not watching.
Footprint tunnel kits can be bought, but they can also be made from scratch at home with just a few bits of material and equipment. Please note that some sharp tools are used, so adult supervision is advised.
What is a footprint tunnel?
A footprint tunnel is small piece of equipment used to capture the footprints of small animals, particularly hedgehogs.
Bait (wet cat or dog food, or specific hedgehog food) is used to lure the animal to centre of the tunnel. To get to the bait, the animal must walk over an ‘ink pad’ (using ink that is safe for animals, and which wears off), and their inky footprints are transferred onto paper.
The paper can then be removed, and the footprints can be measured and analysed to identify which species of animals have visited the tunnel.
What is the ink made from?
The ‘ink’ is made from carbon powder and vegetable oil, and is non-toxic to animals. Carbon powder can be bought online. All-natural or food grade activated charcoal powder should be used.
Avoid using paint, food colouring or ink pads as, although they may be safe for humans to use, there isn’t a guarantee that their ingredients will be safe for other animals.
Footprint tracking ink can be bought online, if you don’t wish to make your own ink.
Can the footprint tunnel be reused?
Footprint tunnels can be reused multiple times, although parts of it may need to be replaced. It’s a good idea to replace uneaten bait every couple of days at a minimum, to prevent it going bad, and to clean out the bait tray.
If you are using cardboard, it may get damaged by rain, dew or frost, or by large animals (such as cats, badgers or foxes) trying to get at the bait.
If you are finding that you’re not recording any footprints, don’t despair. Try relocating your tunnel to other parts of the garden.
How to identify animal footprints
If you are successful in getting footprints in your tunnel, the next step is to work out what they belong to! The shape and size will help you identify them.
Photograph the prints next to a ruler, measuring both length and width.
There are a variety of online resources for identifying animal prints, including RSPB, Wildlife Trust and Hedgehog Street.
More step-by-step guides for catching and identifying wildlife
- How to make a print cast
- How to make a pitfall trap
- How to make a pooter
- How to make a parabolic reflector (pictured)
Illustrations by Alan Batley.
You Will Need
- Cardboard or poster board
- White paper
- Masking tape
- Bait (wet cat or dog food, or specialist hedgehog food)
- Twine
- Carbon powder
- Vegetable oil
- Shallow tray
Step 1
Fold a large square of poster board or cardboard three ways (to make a triangular tunnel), and make holes along the outer edges (which will become the top of the tunnel).
The tunnel length needs to fit at least two A4 pieces of paper, with some additional space for rows of masking tape.
Step 2
Tape the two sheets of white paper onto the middle section, and put bait in the centre. If you use a shallow tray, it will prevent the white paper from becoming discoloured and wet. Make sure to secure the tray.
Step 3
Mix the carbon powder (see above for what type of carbon powder to use) and vegetable oil to create the ‘ink’, using one part carbon paper to one part vegetable oil.
Put down a few rows of masking tape at the ends of the tunnel, then daub the ink onto the masking tape to create ‘ink pads’.
Please note that this illustration featuring paint is old, and the current guidance is to use the carbon powder and vegetable oil mix.
Step 4
Tie the top together using twine. Place the tunnel in a sheltered part of the garden, such as alongside a fence line or hedge. Check the paper in the morning for any prints. If you have got prints, remove the white paper and identify the prints.
If you are reusing your tunnel, you may need to replace the various parts. As mentioned above, it is advised to replace the bait every couple of days and to clean the bait tray.
