When I lived on Long Island one spring summer we had a rat problem. It seems the county was short on money and stopped their rat abatement program. Anyway the rats were out in force. After several of the neighbors complained the village came around with this pretty effective rat trap. It was not the most humane of traps but it worked, and worked well.
They took a plastic barrel, about 55 gallons IIRC. They took a dowel or broom stick, and attached a coffee can to the center of it. At the center of the rim of the 55 gallon plastic drum they cut two notches for the dowel with the coffee can to sit in and spin when turned. They put a board that lead up the side of the barrel and coated the coffee can with peanut butter, then put about 2' of water in the barrel. The rats would go up the plank, reach for the peanut butter and the can would spin and the rats would fall in the water. The trap worked like a charm!
Pellet rifles are cool, this trap works when you want to get some sleep, and you don't have to worry about poisoning the dog.
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