Ground squirrels are small, burrowing rodents found throughout the state, with the exception of extreme East Texas. There are five different species in Texas. These are the thirteenlined ground squirrel, Mexican ground squirrel, spotted ground squirrel, rock squirrel, and the Texas antelope ground squirrel. Most ground squirrels prefer grassy areas such as pastures, golf courses, cemeteries and parks. Rock squirrels are nearly always found in rocky cliffs, boulders, and canyon walls. The rock squirrel and thirteen-lined ground squirrel are the two species that most commonly cause damage by their burrowing and gnawing.
Ground squirrels live in burrows that are usually 2 to 3 inches in diameter and 15 to 20 feet long. The burrow system usually has two entrances. Dirt piles around the entry holes are seldom evident. Rock squirrels and thirteen-lined ground squirrels may hibernate during the coldest periods of winter.
Ground squirrels normally do not cause extensive damage in urban areas. However, they will feed on flowers and vegetables in gardens, and their burrows can be a nuisance. In rural areas, ground squirrels can do extensive damage to cropland or pastures. They may dig up newly planted seeds, eat sprouting plants and weaken earthen dikes with their burrows. Their burrowing and gnawing behavior also can cause damage in irrigated areas.
Ground squirrels can be controlled by a number of different methods. Where ground squirrel populations are high, several control methods may need to be used at the same time. Regular control may be required to prevent re-infestation from surrounding populations.
Rodenticides provide the most economical method for controlling large populations of ground squirrels. Restricted-use pesticides are available but can only be used by a licensed pest control operator or a person who has a private applicator’s license that permits the use of such chemicals. Directions on all toxicant labels should be read, understood and followed exactly. Because ground squirrels are not normally active during the cold winter months, these chemicals should not be used at this time.
Fumigation of burrows is an effective technique. The gas cartridge is a common fumigant that is available from the United States Department of Agriculture supply depot, various feed stores and garden supply centers. Directions on all toxicant labels should be read, understood and followed exactly. When using any fumigant, it is important that the soil contain adequate moisture. Moist soil holds the fumigant in the burrow and prevents it from seeping through the soil. Do not fumigate under buildings. The fumes may seep into the dwelling and create a hazard to the occupants.
Habitat manipulation will sometimes discourage ground squirrel activity. Ground squirrels prefer areas with short grass. Therefore, control can be achieved by allowing the grass to grow into dense stands, which changes the habitat, or by cultivating infested areas, which destroys the burrows.
If ground squirrels are a pest in grain crops, planting grain as early as the weather permits may reduce damage to sprouts that appear before ground squirrels become fully active.
Ground squirrels can be excluded from gardens or flower beds with fences made of either sheet metal or ½-inch hardware cloth. The fence should be at least 18 inches high, with about 6 inches buried in the soil. The fence should completely surround the area to be protected. This costly method usually is practical only in small areas.
Traps are often effective where there is a small population of ground squirrels or in urban areas where a toxicant cannot be used safely. Small cage traps are available from feed stores, sporting goods stores and many garden supply centers. Traps should be baited with grain or oats and placed near the entrance to the burrow.
Rat traps are also an effective way to catch smaller ground squirrels. The traps should be baited and placed near the burrow entrance. Traps with an expanded trigger can be placed in the squirrel’s travel path. Set this way, the trap does not have to be baited. The animal will step on the trigger as it moves along the path.
Periodically flooding the burrows with a few gallons of water may encourage ground squirrels to relocate. In rural areas, ground squirrels also can be shot if local laws, ordinances and safety considerations permit.
Although it is legal to trap ground squirrels at any time, persons wishing to live trap the animals and then relocate them should notify local representatives of the Texas Parks and Wildlife Department.
For additional information, contact the nearest office of the Texas A&M AgriLife Extension Service–Wildlife Services.
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