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
Wallis Bird Festival, Frequency Festival, Rock En Seine, Lowlands and Pukkelpop. In January 2011, Bird toured with Anaïs Mitchell's performance of her album "Hadestown", providing opening support whilst also taking part in the main production of the show. In November 2011, Bird released a special limited edition sole acoustic album (limited to 1000 copies) called "The Mistakes are Intentional". Bird recorded the solo versions in her home in London during the summer of 2011. The CD is packaged in a wallet which has been hand-stitched by Bird herself. Bird made the album in anticipation of the release of her third album. Bird