Two owl species in California are being poisoned, and the culprit might be marijuana farmers.
That's according to a new study published Thursday. The poisoning affects the Northern spotted owl — considered threatened by the U.S. government — and the barred owl.
Pot farmers likely aren't poisoning the owls on purpose, but they are setting poison down for rodents, which owls can eat.
Both species studied weren't anywhere near urban areas. But the areas studied have seen increases in marijuana growing operations. The authors say one of the counties studied has thousands of pot farms with little regulatory oversight.
And the researchers say they're worried legalizing recreational marijuana in California could make the problem worse.
These marijuana operations aren't just hurting owls. A 2015 study linked illegal marijuana farms and the same type of poison to the death of some fishers — a member of the weasel family.
And another study from last year shows pot farms are also hurting the ecosystems these animals live in by causing deforestation and forest fragmentation. Those issues are small now but could become "substantial threats" as cannabis farming becomes more common.