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 sandpiper but is a vulnerable species in some states of Australia. Common sandpiper The common sandpiper ("Actitis hypoleucos") is a small Palearctic wader. This bird and its American sister species, the spotted sandpiper ("A. macularia"), make up the genus "Actitis". They are parapatric and replace each other geographically; stray birds of either species may settle down with breeders of the other and hybridize. Hybridization has also been reported between the common sandpiper and the green sandpiper, a basal species of the closely related shank genus "Tringa". The common sandpiper was one of the many bird species originally described by Linnaeus in