What is a flight call?
The term flight call is one we use to describe the primary vocalization given by many species of birds in long, sustained flights. Many migratory birds regularly give flight calls as they fly in diurnal or nocturnal migration, and most active birders have heard the "seeps" and "zeeps" that can fill the sky at night or early morning during spring and fall. We use the term flight call mostly for convenience because few species, if any, give their flight call exclusively in flight. In fact, for most species, the so-called flight call is given under a wide variety of circumstances. Many species regularly use their flight call while foraging year round. Others use their flight call while interacting with young on the breeding grounds. In some species, Catharus thrushes for example, the vocalization we refer to as the flight call is given mostly by perched birds during the day and given in flight primarily during nocturnal migration. Furthermore, the so-called flight call is not the only vocalization uttered in flight for most species. Many birds sing in flight, with some species, such as pipits, doing most of their singing on the wing. Many species (e.g., Ovenbird, Scarlet Tanager, Indigo Bunting) are even prone to give short bursts of song during nocturnal migration. In addition to flight calls and song, many birds will occasionally give their chip note (a call more associated with perched birds) or other vocalizations while in flight. Yellow-rumped Warblers, for example, regularly give both their chip note and flight call while in diurnal flight (though they seldom give the "chip" in nocturnal migration). The character of the flight call varies widely from one group to another, from the "chuck" of a blackbird to the "seep" of a warbler to the gurgle of a cuckoo. The common denominator is that this call type, the flight call, is the one given most regularly in long, sustained flights, particularly during migration.