Migratory common blackbirds have lower innate immune function during autumn migration than resident conspecifics
Animals need awell-functioning immune systemto protect themselves againstpathogens. The immune system, however, is costlyand resource trade-offs withother demands exist. For migratory animals several (not mutually exclusive)hypotheses exist. First, migrants reduce immune function to be able to allocateresources to migration. Second, migrants boost immune function to cope withmore and/or novel path