Flight feather sounds. Birds of some species produce non‐vocal sounds with specialized sound‐producing flight feathers, which vibrate during rapid movement through the air. When an American Woodcock (Scolopax minor) flaps its wings during an aerial display, air flows through small slits in three outer primary feathers, producing a high twittering sound.
Gregory F. Budney, Macaulay Library
Tail feather sounds. During the high‐speed dive portion of a Common Snipe’s (Gallinago gallinago) courtship display, its outer tail feathers produce a distinctive “winnow” sound as the outer tail feather vanes (arrow) flap rapidly back and forth, much like a tethered flag in the wind. This recording features Wilson’s Snipe (Gallinago delicata), a closely related species that also produces a “winnow” sound as part of its aerial display.
Calls of the Black‐capped Chickadee (Poecile atricapillus). In addition to the “hey‐sweetie” song illustrated in Fig. 10.02, chickadees have other vocal signals.
(A) The “chick‐a‐dee” call is often associated with flock identity. Although this call consists of the same component notes (a–d) in addition to the characteristic “dee” sequence, individuals modify the note order and/or repetition according to the call variety specific to their flock.
(B) Gargle calls are typically given by males during aggressive interactions.
Gerrit Vyn, Macaulay Library
The Superb Lyrebird (Menura novaehollandiae). Lyrebirds are famous for their vocal mimicry of both biotic (other animals) and abiotic (including chainsaws and car alarms) sounds.
Newton Hobbs, Macaulay Library
Repertoires. Many species are capable of singing several song types, which together form a repertoire. Compare the spectrograms of three Common Chaffinch (Fringilla coelebs) song types; each has a distinctive structure and sequence of notes.
(A) Type 1
(B) Type 2
(C) Type 3
Species with large repertoires.
(A) Common Nightingales (Luscinia megarhynchos) can sing hundreds of song types. Each bracket indicates a phrase; together the phrases form a song.
Arnoud B. van den Berg, Macaulay Library
(B) Brown Thrashers (Toxostoma rufum) hold the record for the most song types: one male may sing more than 2,000 song types.
Structure and function of alarm calls.
(A) The high frequency and narrow bandwidth of Tufted Titmouse (Baeolophus bicolor) “zee” alarm calls make them difficult for a predator to locate.
(B) The “shree” alarm calls of an American Robin (Turdus migratorius) fade from loud to soft and cover a range of frequencies.