I have been visiting Peter Becker and Sandra Bouwhuis in Wilhelmshafen, Germany to learn about their research on common terns. Peter has a long-term project and a visit to their field site is an inspiration for our own research questions on the arctic tern. They monitor individuals with transponders and have a automated registration of presence and body mass. New for me is there method of blood sampling. They use tropical tics and hide them in fake tern eggs. They can sample blood without the bird noticing. Ideal for studying hormone levels.