Species-characteristic behaviour patterns functioning in communication as social signals. Both visual and vocal (and mixed) displays exist, but it is common to refer just to the visual performances as 'displays' and to distinguish the vocal ones as 'vocalizations'. Visual displays consist of postures and movements derived from more basic, everyday behaviour patterns, e.g. nest-building movements or thermo-regulatory plumage postures. These have, in the course of evolution, often been modified (ritualized) to some extent to serve their new signal function, becoming stereotyped in form. Displays often are a combination of basically incompatible or conflicting behaviour tendencies; e.g. threat display is associated with attacking and fleeing behaviour. This is called 'ambivalence'. Display movements can be roughly classified into the following categories: 1) threat, 2) submissive (to reduce aggressiveness of more dominant birds), 3) begging, 4) sexual, 5) greeting and nest-relief, 6) social (e.g. in flock integration) and 7) anti-predator.

Alternative forms for display : displaying, displays.