hornets hunt when there is only little light available - humans will call it darkness. like other insects they are attracted to light. if possible, the light should be extinguished for a short time. the hornets will then continue as usual. if it is not possible to put out the light, a glass jar can be used to catch the hornet. with a paper under the glass, the hornet can then be transported to a safe place away from that light where it can be released.