According by Cauderay (1931), Aepyornis was 3 m in height and estimated about 438 kg (Amadon, 1947). Clear Palaeoecological analysis was not yet done. About the cause of extinction, precise identification and it date and diet are needed. We conducted isotope analysis using eggs of modern chicken and Aepyornithidae eggshells and bones. We established methods of stable carbon and nitrogen (δ¹³C and δ¹⁵N) measurements using albumin, membrane and eggshell protein of modern chicken, proteins extracted from Aepyornithidae eggshells and bone collagen. The δ¹³C values of eggshell protein from the modern chicken differed from those of the egg albumin by - 1‰, indicating that eggshell protein can be used for dietary analysis after correction. δ¹³C values from Aepyornithidae eggshell protein and bone collagen suggested that food resources depended on ecosystem containing either C₃　plants　or C₃ type of CAM plants. δ¹⁵N values of Aepyornithidae eggshell protein and bone collagen were similar to those of the Ostrich, suggesting omnivore diet. DNA extracted from Aepyornithidae bones were used for the ancient DNA analysis. As the first result, sample 07AEP02 (genus Mullerornis) sequence of the PCR fragments, showed 98 % homology to the already identified Mullerornis agilis.