A device (1) for trapping animal pests such as caterpillars, having a collar (2) which is designed to surround the trunk of a tree (3). Said collar (2) comprises a substantially annular walkway (4) that extends substantially in a first plane (P1) that is intended to be oriented horizontally. The substantially annular walkway (4) consists at least in part of a plurality of collar sections (6a-6f) that are connected together in a pivoting manner by connecting means (7) in a first direction (I-I) substantially perpendicular to the first plane (P1).