In mid-March, approximately 335 migrating snow and Ross's geese were found dead over a period of several days at Mud Lake and Market Lake Wildlife Management Areas in eastern Idaho. This is the second consecutive year a die-off has occurred in the area.
Tens of thousands of snow and Ross's geese migrate through Idaho every spring on their way to their nesting grounds in the artic. While unfortunate, the deaths of a few hundred geese will have no impact on the overall health of the populations, which collectively exceed 2 million birds.
Fish and Game staff collected nine goose carcasses from both wildlife management areas and sent them to the Idaho Fish and Game Wildlife Health Lab for necropsy. Tissue and samples of forage found in the geese were sent to the Washington Animal Disease Diagnostic Lab. All samples tested positive for phosphine gas, confirming the deaths were caused by some form of phosphide. It is unknown where the exposure occurred.
Idaho Fish Game is working with the Idaho Department of Agriculture and USDA Wildlife Services to provide outreach and education to possible handlers of phosphide products.