Adjusting Movements in Greylag Geese during Pre-roosting and Mass Fleeing
Abstract:Pre-flight and pre-roosting behaviour was observed in a free-living, tame flock of about 150 Greylag Geese Anser anser L. at the K. Lorenz Institut in Grünau, Austria. Observations were made of adjusting movements of single birds, pairs, families and large groups before roosting and in situations of danger. From about half an hour before flight to the roost, the Geese increasingly try to position themselves parallel to one another. This adjusting behaviour is initiated by intensive go-away calls, attention calls; distance calls of flying and approaching Geese, flying Geese or the adjusting movements of other birds. Individual Geese may alternate their orientation to parallel one bird and then another with pair or family members being preferred. Adjusting movements become increasingly frequent towards the time of flight to the roost. During mass fleeing, all Geese behave as a unit. Within seconds, all birds adjust to the first Goose that localizes the danger, that is, the Goose that gives the first alarm call runs into the flock and releases adjusting movements in all other birds. When not all Geese take-off in the same direction during mass fleeing, some may be forced by crashes to alight again, which endangers them. Adjusting behaviour works interspecifically (e.g. Anser anser and Branta leucopsis) and exists in many other bird species (e.g. ducks, doves, starlings, gulls).
Document Type: Research Article
Publication date: December 1, 1990
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- Bird Behavior is an international and interdisciplinary journal that publishes high-quality, original research on descriptive and experimental analyses of species-typical avian behavior, including the areas of ethology, behavioral ecology, comparative psychology, and behavioral neuroscience.