Both sexes give a loud, clicking call, which is used in various situations. The summer tanager is highly migratory, depositing large amounts of fat before the beginning of migration. Migratory flocks can be as large as 30 individuals, though it is not known if these flocks fly together or simply gather when on the ground. Tanagers sometimes join mixed-species flocks, especially at forest edges. At fruiting trees, feeding aggregations often form.
Tanagers generally migrate at night, as shown by the presence of many TV tower casualties.
They also sleep primarily at night, though they sometimes take brief naps during the day. Their flight is swift and direct. The summer tanager often sits still on its perch, and then moves in sudden bursts. Breeding pairs preen frequently, and individuals occasionally sunbathe. After arrival on the breeding grounds, rival males give vigorous flying chases in competition for territory.