So many animals make their homes in the ground that it can be a difficult to know what lives in that hole you're examining. You should learn how to identify ground squirrel burrows, since their homes can be confused with the burrows of dangerous animals.
Measure the opening of the burrow. Ground squirrels will have burrow openings that average around 4 inches in diameter.
Observe whether the hole seems to be one in a collection of holes or whether it is solitary. Most ground squirrels live in a colony in which several animals will occupy the same system of burrows. Each animal will have its own entrance hole, however. If startled, the squirrel will dart for its own hole, even if another entrance is closer.
Determine the depth of the burrow. Though the burrow system can be widespread, ground squirrels will generally burrow less than 3 feet into the ground.
Notice whether the burrow system extends under fences, rocks, logs or other structures. Ground squirrels will often burrow under these objects to keep their burrows safe from predators who may dig into the ground after their prey.
Scrutinize the ground around the burrow. If the burrow is located on sloped ground, then there is a good possibility that it is a ground squirrel burrow. The animals do this to decrease the risk of flooding, and to provide good visibility around the burrow entrances.
Survey the debris in the area just outside the entrance of the burrow. If you find seeds, seed husks and grass clippings, then you have likely identified a ground squirrel burrow.
Note any buildup of sand or soil outside the entrance of the burrow. The squirrels deposit fresh dirt from inside the burrow to build little mounds to increase their visibility. These trademark mounds often grow large enough to trip livestock and humans, and the rocks they contain can ruin machinery. The annoying mounds have made the squirrels targets of agricultural pest control efforts.
Study the surroundings of the burrow. Ground squirrel burrows are located in areas with low grass. These animals will not burrow in areas where there is long grass or shrubs, because the plants would dangerously decrease their visibility.
Ground squirrels are active during the day, so observing the burrow during this time may give you the opportunity to see the animal running in and out of the entrance. Cobwebs, long grasses and filled-in dirt probably indicate that no one lives in that burrow.
Many animals use abandoned ground squirrel burrows as their homes. Never go poking around a burrow without positively identifying the occupant first. Ground squirrels are rodents and can carry parasites and diseases. For example, the fleas on many western species of ground squirrel carry bubonic plague. Don't touch or pick up a ground squirrel unless absolutely necessary.