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 miner Common miner The common miner ("Geositta cunicularia") is a passerine bird of South America, belonging to the ovenbird family. It is a ground-dwelling bird which feeds on insects and seeds. It has about 9 different subspecies, some of which may be better treated as separate species. It is 14 to 16 cm long with a fairly long, slightly downcurved bill. The plumage varies geographically but is basically brown above and pale below with a streaked breast, pale stripe over the eye, dark edge to the ear-coverts and pale rufous bar across the wing. The tail is dark with a buff