The collection of avian voucher specimens has long played an important role in studying the basic biology, ecology, and evolution of birds. However, symbionts (such as parasites and pathogens) of avian hosts have been largely neglected by ornithologists and are largely underrepresented in most major museum collections. Museum-oriented research expeditions to collect bird specimens capture a diversity of metadata, but the proper collection of symbionts for optimal use in downstream research projects remains uncommon. In this chapter, we provide methods for the comprehensive sampling of a diverse suite of symbionts from avian hosts, including blood parasites (haematozoans), microbial symbionts (bacteria and viruses), ectoparasites (arthropods), and endoparasites (helminths), while attempting to illustrate the research avenues opened by collecting such samples. Our objective is to encourage a view of birds as ecosystems in and of themselves, and to empower field ornithologists, particularly those participating in the collection of voucher specimens, to sample the plethora of micro- and macroorganisms that live in and on avian hosts. By collecting these additional specimens, ornithologists will not only unlock new aspects of avian biology, but also will expand the scientific community’s ability to address ecological and evolutionary questions, while aiding in the discovery of new biodiversity and maximizing the utility of the “extended” avian specimen.