White animal colourations are often maladaptive given that prey or predators can easily spot them in most natural environments. However, white colorations can be still found in nature when light-coloured backgrounds are available, for instance, in bird predators hunting against a clear sky or in animals living in habitats often covered by snow. Barn owls often exhibit an immaculate white ventral plumage, which is unique among nocturnal birds of prey. However, barn owls hunt and habit in habitats lacking any obvious light background, and the function, if any, of such unusual coloration remains a mystery. Recent findings suggest that the white plumage of the barn owl might have evolved as a unique adaptation to increase hunting success. However, different aspects of this hypothesis still need to be formally confirmed using field and laboratory experiments.

The successful applicant will conduct both field and laboratory experiments with barn owls and wild rodent species, respectively.

The student will learn how to design and conduct experiments in both field and laboratory circumstances and with fully different species as well as to collect and analyse the data. The study will provide new insights into a novel and rare adaptation in the animal kingdom and into the mechanisms that maintain colour variation in this ubiquitous animal species.

References:
Endler Westcott DA, Madden JR, Robson T JA (2005) Animal visual systems and the evolution of color patterns: Sensory processing illuminates signal evolution. Evolution, 59, 1795–1818.
Gamble S, Lindholm AK, Endler J a., Brooks R (2003) Environmental variation and the maintenance of polymorphism: The effect of ambient light spectrum on mating behaviour and sexual selection in guppies. Ecology Letters, 6, 463–472.
Roulin A (2004) The evolution, maintenance and adaptive function of genetic colour polymorphism in birds. Biological Reviews, 79, 815–848.

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