Sounds

Development

No information.

Vocal Array

Whether the diurnal Snowy Owls rely less on acoustical signals than other owls is a subject not well researched. The distinction between song and call in this species also merits further study, especially with reference to hooting. Although both sexes are known to hoot, it appears to be rare in females while common in males. Hooting probably serves as song at times, especially when mutual hootings occur among territorial males that may even face one another in threat posture (Watson 1957). Sutton (1932) witnessed as many as a dozen males hooting at once. One of these birds seen close up lifted his head, swelled out his throat enormously, elevated his tail until it stuck almost straight up, and gave four long, low hoots, bowing violently each time he hooted. Booming hoots answered from the ridges far and near. Hoots described as a local hoo, hoo, usually double, but sometimes six or more, the last often the loudest, with 1- or 2-second intervals after each (Watson 1957). Variants a deep hoo, and a long drawn-out hooooo . Hoots sometimes thought to have a ventriloquial quality, so that they seemed to come from high in the air or from the ground (Sutton 1932). Also, they carried a great distance (heard up to 7 mi by Sutton). Males hooted not only from ground or perch, but also commonly during flight.

Taylor’s (1973) observations confirm those of Sutton (1932) and Watson (1957). He reported that the “territorial hooting display” or song is similar to that of the Great Horned Owl, and that hooting volume is loudest in the context of territorial defense. Taylor’s drawings of the attitudes of males during territorial hootings (Fig. 4) are similar to Sutton’s description though somewhat less exaggerated.

Other than hootings, owls give several vocalizations, usually when disturbed near their nests. Different renditions and interpretations occur in the literature, all of which warrant more thorough study. One of the loudest and most often heard by Thaxter (1875) is the so-called watchman’s rattle, likely the rick, rick, rick heard by Wheelwright (in Witherby et al. 1952), and kre, kre, kre, kre, kre which reminded Watson (1957) of a Corncrake (Crex crex). Sutton and Parmelee (1956) rendered it as a barking ha, how, quack, quock, or quawk, sometimes repeated in wild volley, usually by the male although both sexes used it. The call is given commonly during flight and also from a perch. It appears to function as a threat, often becoming louder and more frequent as a human approaches a nest.

Females frequently give a call described as a whistling or mewing call (Watson 1957), which occurs before and after feeding by the male, during distraction display, and in displacement coition. Watson heard this call from females only, and Sutton and Parmelee (1956) heard it from only one of many males they observed. A crowed ca-ca-oh is given by attacking females but not recorded for males (Sutton and Parmelee 1956). Males give a low, rapid, cackling ka-ka-ka-ka-ka-ka in displacement coition or when alighting on a favorite perch (Watson 1957). A similar though often higher pitched ke-ke-ke-ke-ke is given by females before displacement coition, at the start of pre-coition display, and when feeding young.

Both sexes hiss when threatened. Although chicks cheep soon after hatching, they do not begin hissing until about two weeks old (Watson 1957). A juvenile call seldom reported is a shrill squeal given by unfledged owlets that have left the nest and are dispersed over the tundra. For a human to hear these rending screams issuing from a multitude of hiding places, and not to know their source, is a perplexing experience. Likely this call functions in helping the male find his scattered young; before each young he drops a freshly killed lemming (Parmelee 1972). Presumably these calls persist until the parent-offspring bond breaks.

Phenology

Except for Evans (1980), who observed wintering birds within a small defended area conducive to territorial behavior, few details have been reported concerning vocalizations outside the breeding season. He stated that during daylight, owls maintain territories by vocalizations accompanying agonistic displays, chases, and even attacks. Intrusions elicit high-pitched, drawn-out screams from a resident owl (“territorial screaming display” of Evans), accompanied by an attitude similar to that described by Taylor (1973) for the territorial hooting display. At maximum display it resembles the display described for hooting males by Sutton (1932) with particular reference to the tail, which is held nearly perpendicular to the ground. Flying intruders elicit stronger responses than perched owls.

Wintering birds also utter a series of 10 to 15 soft grating sounds accompanying a territorial screaming display (Evans 1980). This may be the sound described by Sutton (1932) as “heavy teeth grinding together.” Owls also scream without an agonistic display. Perched birds may give extremely soft melodious warbling sounds (2–3 s) and a low-pitched, two-syllable grunting sound after flying from the perch (Evans 1980).

Daily Patterns

Highly vociferous at all hours during the irregular nestings, but otherwise mostly silent year-round.

Sexual Differences

In addition to differences in vocal array, males are generally much more vocal than females, at least during nesting. This difference may be related to the male’s greater share in defense of nest and territory (Watson 1957).

Places Of Vocalizing

Usually an often used prominence within the territory.

As in many owl species, Snowy Owls snap their mandibles loudly when threatened. Owlets only 8 to 10 days old engage in bill snapping when handled (Watson 1957).