Chromaticity in the UV/blue range facilitates the search for achromatically background-matching prey in birds
2009 (English)In: Philosophical Transactions of the Royal Society of London. Biological Sciences, ISSN 0962-8436, Vol. 364, no 1516, 511-517 p.Article in journal (Refereed) Published
A large variety of predatory species rely on their visual abilities to locate their prey. However, thesearch for prey may be hampered by prey camouflage. The most prominent example of concealingcoloration is background-matching prey coloration characterized by a strong visual resemblance ofprey to the background. Even though this principle of camouflage was recognized to efficiently workin predator avoidance a long time ago, the underlying mechanisms are not very well known. In thisstudy, we assessed whether blue tits (Cyanistes caeruleus) use chromatic cues in the search for prey.Weused two prey types that were achromatically identical but differed in chromatic properties in theUV/blue range and presented them on two achromatically identical backgrounds. The backgroundshad either the same chromatic properties as the prey items (matching combination) or differed intheir chromatic properties (mismatching combination). Our results show that birds use chromaticcues in the search for mismatching prey, whereupon chromatic contrast leads to a ‘pop-out’ of theprey item from the background. When prey was presented on a matching background, search timeswere significantly higher. Interestingly, search for more chromatic prey on the matching backgroundwas easier than search for less chromatic prey on the matching background. Our results indicate thatbirds use both achromatic and chromatic cues when searching for prey, and that the combination ofboth cues might be helpful in the search task.
Place, publisher, year, edition, pages
2009. Vol. 364, no 1516, 511-517 p.
visual search; crypsis; predation; avian vision; luminance; colour;
Research subject Animal Ecology
IdentifiersURN: urn:nbn:se:su:diva-30543DOI: 10.1098/rstb.2008.0248ISI: 000262353500011OAI: oai:DiVA.org:su-30543DiVA: diva2:272844