Common cuckoo lay eggs that better imitate the host's eggs, the host species adapts and is more able to distinguish the cuckoo egg. A study of 248 common cuckoo and host eggs demonstrated that female cuckoos that parasitised common redstart nests laid eggs that matched better than those that targeted dunnocks. Spectroscopy was used to model how the host species saw the cuckoo eggs. Cuckoos that target dunnock nests lay white, brown-speckled eggs, in contrast to the dunnock's own blue eggs. The theory suggests that common redstarts have been parasitised by common cuckoos for longer, and so have evolved to be better
Common blackbird dark Places about it", and it symbolised resignation in the 17th century tragic play "The Duchess of Malfi"; an alternate connotation is vigilance, the bird's clear cry warning of danger. The common blackbird is the national bird of Sweden, which has a breeding population of 1–2 million pairs, and was featured on a 30 öre Christmas postage stamp in 1970; it has also featured on a number of other stamps issued by European and Asian countries, including a 1966 4d British stamp and a 1998 Irish 30p stamp. This bird—arguably—also gives rise to the Serbian name for Kosovo, which is