Experimental and analytical techniques used in bird orientation research.

Our present understanding of orientation behaviour in birds is based on a broad array of observational, experimental and analytical (statistical) techniques, which are briefly reviewed here. As an extremely productive model the homing behaviour of pigeons has allowed especially diverse experimental manipulations documenting the involvement of magnetic, visual and olfactory cues in orientation. Work with migratory birds has profited greatly from the design of several kinds of orientation cages, now commonly used, and from hand-rearing test birds under controlled conditions. Free-flying birds, especially on long-distance migration, are still least amenable to study, but radio transmitter technology is providing important new opportunities in this respect. In general, the most valuable studies have been those involving the ontogenetic development of orientation, and those combining several methods of investigation. Some suggestions for further experiments are made.