Zur Funktion von Warnfarben: Die Reaktion junger Stare auf wespenähnlich schwarz-gelbe Attrappen

Abstract

Hand‐raised starlings (Sturnus vulgaris) at an age of six weeks initially rejected black and yellow banded insect dummies at a higher rate than green, yellow or brown ones. The results indicate that in starlings the following principle holds: “There is an initial tendency to avoid warningly coloured prey which for a permanent avoidance must be supplemented by unpleasant experience.” Individual differences in the tendency to avoid a pattern, such as those observed, provided the variation from which natural selection could mould — in cases of dangerous warningly coloured prey — innate avoidance reactions. Zusammenfassung 17 handaufgezogene sechs Wochen alte Stare (Sturnus vulgaris) lehnten in Wahlversuchen schwarz‐gelb geringelte Insektenattrappen (vgl. Abb. 1) anfangs mit größerer Wahrscheinlichkeit ab als einfarbige grüne, gelbe oder braune (Abb. 2, 3). Bei 13 Wochen alten anderen Versuchstieren derselben Aufzucht war diese Ablehnungstendenz nicht nachzuweisen. Die Befunde sprechen dafür, daß beim Star das Prinzip “anfängliche Tendenz zum Meiden warnfarbiger Beute, die durch unangenehme Erfahrung ergänzt werden muß” gilt. Dieses Prinzip vermittelt zwischen der angeborenen und der erlernten Meidereaktion. Individuelle Unterschiede in einer Ablehnungstendenz, wie die Stare sie zeigten (Abb. 4), bilden die Variation, aus der Selektion in Fällen gefährlicher warnfarbiger Beute angeborene Meideraktionen formen konnte.

The survival value of countershading with wild birds as predators

“…However, there is an alternative explanation (for which we are grateful to our referees for drawing to our attention): it is possible that birds see two-tone prey just as easily as uniformly green prey, but avoid eating it for some reason unrelated to camouflage (see for example Coppinger ( 1969, 1970), Smith ( 1977, Schuler ( 1982), Tinbergen & Perdeck ( 1950), for innate aversions and preferences to certain colours). However, if predators had an inhibition about attacking two-tone prey then we can make two predictions.…”

Butterfly visual characteristics and ontogeny of responses to butterflies by a specialized tropical bird

“…Several past studies on bird feeding behaviour have demonstrated initial inhibition toward attacking or handling novel, conspicuously coloured prey by naive, handreared young of at least some species (Coppinger, 1970;Smith, 1975Smith, , 1977Schuler, 1982;Greenberg, 1984; but see Alcock, 1973;Barrows et ul., 1980;Smith, 1983 for exploratory behaviour in young). In the beginning of feeding experiments, the young did not exhibit any indication of fear of novel, conspicuously patterned butterflies, and there was no initial preference shown by any of the three young birds toward attacking butterflies with particular visual characteristics.…”

Sound improves visual discrimination learning in avian predators

“…Conspicuous coloration is particularly effective as a warning signal, as avian predators learn to avoid unpalatable prey faster if they are conspicuously coloured rather than if they are cryptic (Gittleman & Harvey 1980;Roper & Redston 1987), and there is also evidence that birds may instinctively avoid food that has colour typical of aposematic prey (Schuler 1982;Schuler & Hesse 1985;Roper & Cook 1989;Gamberale-Stille & Tullberg 2001). However, many aposematic insects do not just use colourful signals, but also often emit odours or sounds when they are approached or attacked by a predator (Cott 1940;Rothschild 1961;Rothschild & Haskell 1966;Edmunds 1974).…”