Controlling ground squirrels
When it comes to controlling ground squirrels, the earlier the better.
“Removing adult animals in early spring has the advantage of eliminating up to six times as many animals that otherwise would appear later in the year,” said John Bourne, pest prevention and management specialist with Alberta Agriculture.
Poison baits are the most common control. Two types are available: anti-coagulants and non anti-coagulants (such as strychnine and zinc phosphide.)
Zinc phosphide (two percent) ZP is a grain base bait. The strychnine formulation is a 0.4 percent, ready to use, pre-mix bait on whole cereal or cereal pellets.
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The anti-coagulant poison is available in a liquid concentrate for mixing with grain or in a prepared pellet.
Always wear gloves when handling chemicals and dead rodents.
Pyrotechnic fumigants (gas cartridges) such as Woodchuck Bomb or Giant Destroyer produce toxic sulfur gases when ignited that suffocate the rodents in their burrows. These fumigants could start a fire and should be used only where the risk is low.
“In lawns, gardens, school grounds, cemeteries or other small areas where there are only a few ground squirrels, use traps, burrow fumigants or drown them with the garden hose,” Bourne said. Live capture traps should be used when pets and children are nearby.
“Ground squirrels emerging from hibernation in early spring may not appear to be feeding and therefore the use of baits may be questionable,” he said.
However, studies show success if the rodents are conditioned to take bait by setting out untreated grain at burrow entrances five to 14 days before putting out poisoned bait. The pre bait should be the same grain as the poison bait.
Ground squirrels appear to prefer hulled cereals such as oats or barley. Place a tablespoon or two of the pre-bait inside each active burrow entrance, or put a large quantity in a bait station centrally located to several active holes.
Following the pre-baiting period, place the bait mixed with the anti-coagulant poison in the same fashion. If using anti-coagulant concentrate, follow label instructions carefully and always use clean, hulled grain.
“Anti-coagulants only work if the animal consumes at least two or three consecutive daily feedings,” he said. Bait stations should be kept filled until all feeding ceases, perhaps as long as three weeks.
Make bait stations by cutting a pipe about one metre long and about 10 centimetres in diameter. Secure it to the ground with iron stakes, rocks on either side or make a set of legs by cutting a couple of slits about five cm into the pipe on the underside and inserting pieces of metal siding or thin plywood. Place the bait between the ‘legs’ inside the pipe to keep it contained in the bait station.
Plastic bait feeders are available commercially, added Bourne.
Poisoned ground squirrels can pose a danger to pets and other scavengers so they should be buried deep or burned in an incinerator.
– Alberta Agriculture
