OLYMPIA, Wash. -

Wildlife agents have killed four nutria -- rodents the size of beavers -- that have made themselves a nuisance at Capitol Lake in Olympia.

The state Department of Enterprise Services, which manages the lake, hired the U.S. Department of Agriculture's wildlife division to shoot the animals.

The Olympian reports several dozen nutria are thought to infest the lake. The four animals were shot in the past month at night or early morning hours when they are active. Agents use muffled .22-caliber rifles. More nutria killings will be scheduled.

Nutria are an invasive species that were brought to Washington in the 1930s for the fur industry.