Red Squirrels and their dreys (resting places) receive full protection under Schedules 5 and 6 of the Wildlife and Countryside Act 1981 (as amended). It is therefore an offence to intentionally or recklessly kill, injure or take a Red Squirrel, but they can be trapped with a licence. Anyone trapping in an area where Red Squirrels are present (typically for monitoring purposes) should be using live capture traps. These must be checked regularly and the squirrel released unharmed. Greay Squirrels receive no such protection. Traps used to catch Grey Squirrels are typically lethal kill traps because under the Invasive non-native (alien) animal species regulations (which came into force in December 2019) it's illegal to release a trapped Grey Squirrel back into the wild (or keep them as pets or let them breed or escape). 'Humane' live capture Grey Squirrel traps are still sold (so simply baited cages that hold an animal until release), but the majority of traps are 'spring traps' - either metal mesh cages (often mounted in a tree) or Fenn-style ground-based wooden boxes. Both are slightly larger than a squirrel with (usually) a baffled entrance. The traps are baited, often with hazelnuts, and close shut when a squirrel enters. As the squirrel reaches for the bait a plunger is triggered which crushes the animal's head or a powerful spring bar is triggered which snaps shut. Some designs trigger CO2-filled gas canisters.   The law states that only approved spring traps can be used and that traps are set in natural or artificial tunnels to reduce the risk of killing so-called 'non-target' species.