The number of Tundra swan in an arctic refuge has been steadily dwindling  It has been determined that the majority of the birds have died from lead poisoning, which is contained in the buckshot that hunters use to kill the swan
Local authorities have responded by banning hunting, and the number of hunters cited has since dropped dramatically, yet the number of birds that continue to die each month from lead poisoning has not changed
Eventually, there will be so few swan left in the refuge that the overall number of swan dying each month will decrease.