Testing The Protective Function of Flash Coloration Using Wild Avian Predators

Abstract

Many prey reveal conspicuous color patches during movement that become concealed when they stop. Such abrupt changes in appearance have been proposed to disrupt predator tracking and make prey more difficult to relocate, providing the basis of the flash coloration hypothesis. However, empirical support remains inconsistent and comes largely from experiments using human observers or simplified artificial prey. Here, we used touchscreen-equipped operant chambers to test the flash coloration hypothesis with wild blue tits (Cyanistes caeruleus) searching for moving digital prey modelled on Catocala moths. The digital prey revealed either conspicuous or cryptic hindwings during flight before adopting a cryptic resting appearance. Contrary to predictions, conspicuous hindwings neither increased prey survival nor delayed prey relocation compared to moths with cryptic hindwings. However, conspicuous hindwings also did not incur detectable predation costs. In contrast, background strongly affected prey detection, with moths surviving better on realistic bark than on smooth grey backgrounds. Our results provide no evidence that conspicuous colors revealed during movement enhance prey survival in this context, suggesting that any protective effect attributed to flash coloration may be weak or strongly dependent on ecological conditions.