Study
Propagating waves in starling, Sturnus vulgaris, flocks under predation
Procaccini, A.; Orlandi, A.; Cavagna, A.; Giardina, I.; Zoratto, F.; Santucci, D.
Animal Behaviour, 2011
Flocks were filmed during natural raptor attacks and at other times, and the dark bands that sweep across a flock were analysed for their speed, direction and relationship to the attacking bird.
- Studied in
- Sturnus vulgaris, Falco peregrinus
- Sample size
- filmed flock events with and without raptor attack
The dark bands are waves of local density and orientation change propagating across the flock, associated with predator attack, and travelling faster than individual birds move.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
The waves are a collective response to predation, propagating information about an attack through the group.
How NatureHQ reads it
A satisfying explanation of the most conspicuous thing about a murmuration. The dark rippling bands are not birds changing colour or the flock thickening as a whole; they are local changes in density and in how many birds present their wing surface, travelling as a wave — and they travel faster than any bird does, because what moves is the pattern, not the birds.
- Observational, with attacks occurring naturally rather than being manipulated.
- Establishes that the waves accompany attacks; what each bird gains from participating is not measured.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Elsevier journalsPublished in an Elsevier journal.
doi.org/10.1016/j.anbehav.2011.07.006
Checked against Crossref on 2026-09-28, and they agree on the title, the authors and the year.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-09-03.