Molecular diet analysis of common cranes (Grus grus) under supplementary feeding based on fecal DNA metabarcoding

Jiangsu Yancheng Wetland Rare Birds National Nature Reserve provides a wetland ecosystem crucial to rare wildlife. Common crane (Grus grus) is one of the migratory birds that overwinter here. While it is well known that it is omnivorous crane, we lack detailed dietary information for plant-based food composition and dietary changes, with the increase of agricultural lands and other human activities in the protected area. In this study, we used DNA metabarcoding of plants through chloroplast rbcL gene to investigate the diets of 25 common crane fecal samples and performed analyses in conjunction with artificial supplementary feeding. The results showed that common cranes will prefer to eat economic crops such as barley and corn than wild plants, when performing supplementary feeding by the protected area staff. Due to the limitation of DNA metabarcoding technology, some sequences just could be identified at the family level instead of the genus level. This study could contribute to develop and apply a novel method to study the diet of common cranes under supplementary feeding and to further reveal the effect and significance of protected areas management.