Bird eggs vary considerably among species in the colour of their shells and the patterns that adorn them. They may be white or chocolate brown, glossy turquoise or brick red, violet or emerald green. They may be immaculate or covered in scrawls, speckles and blotches. The extent of variation is remarkable, but it is spread unevenly across bird taxa (Kilner 2006).
Our research has investigated the diverse factors that account for variation in bird egg colouring (Langmore et al 2005, Langmore et al 2009, Stoddard et al 2011) and patterning (Stoddard et al 2012, Stoddard et al 2014).
We have also investigated how nourishment of the egg affects the phenotype of the hatchling (Russell et al 2007).
And our experiments even suggest that mothers communicate with their developing offspring within the egg, by depositing hormones and other cues within (during oogeneis) that indicate the quality of the nutritional environment after hatching (Hinde et al 2009). Offspring adjust their begging behaviour according, becoming more demanding when there is the prospect of greater rewards (Hinde et al 2010). When this system of pre-natal communication is disrupted experimentally, offspring grow more poorly as a result (Hinde et al 2010).
Hinde, C. A. et al 2009 Prenatal environmental effects match offspring begging to parental provisioning. Proc R Soc B 276:2787-2794
Hinde, C. A. et al 2010 Parent-offspring conflict and coadaptation. Science 327:1373-1376
Kilner, R. M. 2006 The evolution of egg colour and patterning in birds. Biol Rev 81:383-406
Langmore, N. E. et al 2009 Are dark cuckoo eggs cryptic in host nests? Anim Behav 78:461-468
Stoddard, M. C. et al 2011 Imperfectly camouflaged avian eggs: artefact or adaptation? Avian Biology Research 4:196-213
Stoddard, M. C. et al 2012 Egg speckling patterns do not advertise offspring quality or influence male provisioning. PLoS ONE 7:e40211