Eared Quetzal has a variety of very conspicuous vocalizations, by which most individuals are detected in the field (Lammertink et al. 1996). Its song is a series of 1 or 2 syllable whistles that begin softly and progressively get louder and turn to 3 syllables; it may be written as eeep eeep EEEP EEEP EEEP or whee whee wheerr-I wheerr-I wheerri-hi wheerr-i-hi …, with usually 8-15 whistles in a series but up to 24 and it carries well (Howell and Webb 1995). These notes have a reedy, slightly shrill, quavering quality that has been described as a series of melodious tremolos in a minor key (Howell and Webb 1995, Zimmerman 1978). This song is apparently reminiscent of begging nestling falcons, and the quetzal responds immediately to playback of it, approaching the observer and perching high into a tree (Zimmerman 1978). It is heard often during the breeding season (Lammertink et al. 1996) and apparently is used for mating and territoriality (Taylor 1994). A foraging pair that is separated maintains contact with this song, and when together utters it softly (Zimmerman 1978).
For a representative audio recording with sonogram, see audio
Another call used only by pairs is a weee call, apparently to announce each other’s location. It sounds like a squeaky door hinge and seems loud but the bird may be very near the observer (Taylor 1994).
Eared Quetzal’s most distinctive call is an ascending squeal, similar to Great-tailed Grackle (Quiscalus mexicanus), that is followed by a softer cluck sound and may be written as wheeeuh chk (Howell and Webb 1995). It may be given repeatedly and is accompanied by a pronounced tail pump and a head-jerking motion (Zimmerman 1978). It is the loudest vocalization of the bird’s repertoire, audible up to 400 m away, and seems to be used to announce intruders, including humans and other quetzals (Taylor 1994). This is the call given by the males when approaching the nest (Lammertink et al. 1996).
In flight or when disturbed, the birds give a rapid, sharp, cackling call, usually multiple times, that may be written as kac-ka-k-kac. In flight, it often is accompanied by tail flashing (Taylor 1994).