Why do bird eggs look so different?

Natural selection of the avian eggshell is based on opposing goals. The shell must withstand the breaking forces imposed upon it during incubation, but also be sufficiently fragile to allow successful hatching. Furthermore, deviations from the norm in a specific eggshell trait may reflect unusual selection pressures acting on that trait. For example, a perfectly spherical egg is generally considered to be ‘strongest’ shape for an egg, yet pear-shaped eggs are less likely to roll out of the nest or off a cliff ledge (instead they roll in a tight circle).

For my Postdoctoral Research at the University of New England (May 2014-May 2015) I ask, how does the strength and shape of avian eggshells vary among species, and is this variability associated with species life-history, reproductive and nesting traits?

For this I have microCT scanned hundreds of bird eggs to compare differences in egg shape, thickness and strength across over 50 Australian bird species using multi-disciplinary techniques. Please stay tuned for the findings soon to come!