killing pests
(1) It is a defence to a charge under section 19(1) for a person to prove —
(a) that the act alleged to constitute the offence was done while the person was attempting to kill pests;
(b) that the person was attempting to kill pests in a manner that is generally accepted as usual and reasonable for killing pests of the kind the person was attempting to kill; and
(c) if the animal the subject of the charge was not a pest, that the person took reasonable steps to ensure that animals other than pests would not be harmed.
(2) In this section —
pest means a prescribed animal, fish or invertebrate.