Sounds

Development

Downy young beg with clear, sharp, repeated “peep,” length of each note increasing with age. As young approach fledging, they adopt juvenile food call similar to adult’s Whinny Call, and used for several months after fledging (Buckley et al. 1985).

Vocal Array

Calls of Adults. From Buckley et al. 1985; descriptions for boreal S. m. maxima: (1) Alarm Call. Loud, hard “ Keet Keet ” or “ Krit Krit ” given in flight or on ground when threatened. (2) Kleer Call. “ Kleer kleer ” given when danger has passed as birds return to land on nest sites. (3) Gakkering Call. Series of rapidly repeated, hoarse “ Ack-ack-ack-ack ” notes, expressing threat or alarm; given in aggressive encounters by sitting or standing birds, together with lunging, gaping, and dueling; also directed at aerial intruders; similar but shorter series given by 2 birds encountering each other when fishing or flying over colony. (4) Advertising Call. Throaty “ Kir-reet ” or “ Keer-reet ” given in ground and aerial courtship, especially by advertising male and by both sexes arriving at colony with fish and/or for nest relief. Probably identifies mates to each other and to offspring. (5) Aack Call. Deep, drawn-out, guttural “ Aack-aack ” given by both members of pair during aerial courtship; apparently recognition call answering other’s Advertising Call. Variable in intensity; more clipped version given by incubating bird in response to Advertising Call of approaching mate. Soft “ Ack-ack ” often given in ambivalent situation; e.g., when bird seems hesitant about sitting on egg. A long “ Aack ” may grade into a soft “ Ack .” (6) Whinny Call. Sibilant, whinnying “ Whee-whee-whee-whee ” given by female in Hunched Posture before copulation. (7) Undescribed call given by male during mounting and copulation. (8) Undescribed call used to coax young from nest.

None known for this species.