Blue tits (Cyanistes caeruleus) are now some of the most common songbirds in European woodlands, parks and gardens. Their characteristic blue caps are important in blue tit social life. They can distinguish ultraviolet light and the more reflected by the blue caps the more attractive the males are for breeding. Which doesn't stop the females from a fair share of extramarital breeding.
blue tittitsmeespimpelmeesCyanistes caeruleusbirdsvogelsEuropean birds