Heligoland trap

A Heligoland trap (or funnel trap) is a large, building-sized, funnel-shaped, rigid structure of wire mesh or netting used to trap birds, so that they can be banded or otherwise studied by ornithologists.

The name is taken from the site of the first such trap, the Heligoland Bird Observatory on the island of Heligoland, Germany, where it was developed by Hugo Weigold who established the observatory and initiated the banding program there. The trap has a series of linked funnels that guides birds or other animals in but makes it hard for them to leave. Funnel traps of smaller size can also be used to trap squirrels and insects.