Each preserved edge of each eggshell fragment was measured for thickness, and the average was calculated from the means of each specimen's thickness. Eggshell areas were calculated from digital photographs of the specimens using ImageJ. For specimens of Diamantornis, whole and half-pore complexes (along broken edges) were counted for each specimen. Each preserved whole pore complex was measured for length (greatest diameter) and width (maximal value taken perpendicular to length). Half-pore complex diameters were not computed, but half-pore complexes were included in calculation of pore complex density for each specimen (0.5 pore complex). Pore complex mean diameter was calculated as the combined average of every complete pore complex's mean diameter, calculated as (length+width)/2. The 10 Yale Peabody Museum specimens display significant abrasion of pore complex rims and as a result were not included in pore complex diameter measures. For specimens of aepyornithid-type eggshell, the variation in pore morphologies was assessed across specimens. Eggshell cross-sectional microstructure (e.g., Grellet-Tinner 2000), was not considered. Microstructural analysis of Diamantornis eggshells was undertaken by Dauphin et al. (1996). The UAE eggshells were assigned on the basis of eggshell thickness, and pore complex shape, size, and density.