A taken barred owl is not done so in vain. From each removed barred owl, biologist Mark Higley takes as much information as possible from body measurements, blood and stomach samples, to feather morphology and photos. To just kill them would be criminal, he says. The data he gathers can reveal a lot about the birds and at times, the health of northern spotted owls. Samples taken from organs of removed barred owls have shown the impacts of poisons in the forests tied to trespass cannabis grows. Important information for the health of wildlife in general, but especially northern spotted owls, which share territory and prey.