An apparatus for controlling animal pests comprises a housing having a passage extending into the housing from an entrance, an impacting member movable across the passage and a planar sensor spaced apart from the kill bar by a predetermined distance along the passage towards the entrance, the planar sensor configured to sense the presence of the animal pest across a sensing plane across the passage wherein the impacting member is operable to be released to rapidly move across the passage when the planar sensor indicates the presence of the animal pest as passed through the sensing plane.