The Reactions of Common Rats to Four Types of Live-Capture Trap

(1) Common rats (Rattus norvegicus) enter traps less readily than many other small mammals. Two new designs of multi-capture trap were compared with two other multicapture traps embodying a non-return door system. The new traps incorporated a bait hopper, to facilitate long periods of pre-baiting, and a non-return door system that remained outwardly unchanged when the traps were set after pre-baiting. (2) One of the new traps caught a higher proportion of rats in an experimental colony than any of the other traps and was subsequently compared in the field with a commercially produced trap. Although the new trap caught fewer rats than the commercially produced trap, it caught a higher proportion of the rats feeding from it during prebaiting.