The northern spotted owl, the bird that brought down the Pacific Northwest timber industry, is circling California’s newly legalized marijuana market.
A study led by University of California Davis researchers and released Thursday found that two owl species—the northern spotted owl and barred owl—are being exposed to high levels of rat poison from illegal marijuana grows in northern California.
The problem is expected intensify in the wake of California’s Proposition 64, passed in 2016, which legalized recreation marijuana for adults 21 and over and went into effect Jan. 1.
“Proposition 64, which legalizes recreational marijuana in the state, took effect this month,” said the UC Davis press release. “With its arrival, resource managers expect the number and size of unpermitted, private cultivation sites to grow, which could exacerbate the problem.”
The study, published in the journal Avian Conservation and Ecology, found that “seven of the 10 northern spotted owls collected tested positive for rat poison, while 40 percent of 84 barred owls collected also tested positive for the poison.”