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
European Bird Census Council forces behind population changes and use common bird indicators as a proxy for environmental health, and thus inform policy. Monitoring data is published as the European Breeding Birds Atlas, the second of which (EBBA2) is currently in preparation. The data collected as part of the PECBMS and EBBA2 programmes is also distributed on the EBCC-run portal, EuroBirdPortal, as well as through the Global Biodiversity Information Facility (GBIF). The EBCC run a conference every three years, devoted to ornithological monitoring, conservation and research in Europe and abroad. The organisation also publishes the Journal of the European Bird Census Council, entitled "Bird