Irene Di Lecce, Joanna Sudyka, David F Westneat, Marta Szulkin

Collecting and storing biological material from wild animals in a way that does not deteriorate data quality for analyses using DNA is instrumental for research in ecology and evolution. Our aims were to collect methods commonly used by researchers for the field collection and long-term storage of blood samples and DNA extracts from wild birds and gather reports on their effectiveness. Personal experiences were collected with an online survey targeted specifically at researchers sampling wild birds. Many researchers experienced problems with blood sample storage but not with DNA extract storage. Storage issues generated problems with obtaining adequate DNA quality and sufficient DNA quantity for the targeted molecular analyses, but were not related to season of blood sampling, access to equipment, transporting samples, temperature and method of blood storage. Final DNA quality and quantity were also not affected by storage time before DNA extraction or the methods used to extract DNA. We discuss practical aspects of field collection and storage and provide some general recommendations, with a list of pros and cons of different preservation methods of avian blood samples and DNA extracts.