Vocalizations and
Behaviour
Nine different calls were used by breeding and non breeding Red throated
Loons on a lake in coastal British Columbia, Canada.
All vocalizations were low frequency (<3 kHz) with multiple harmonics and
many had a "noise" overlay. The calls can be classified as (1)
territorial (Wail, Plesiosaur, Quack), (2) alarm (Wail, Kark) and (3)
contact/feeding (Coo and Extended Coo, used by the male; Low Shrill and High
Shrill, used by the female; Staccato, used by both sexes). Sexual dimorphism
occurred in the Wail, with that of the female higher in frequency, and in the
Plesiosaur call, with female and male calls markedly different in vocal
structure. Visual displays that may influence the production of calls were
associated with the Plesiosaur call and Wail; both of these calls and displays
were usually performed in duet. The repertoire of calls in Red-throated Loons
was greater than in Common Loons. This may reflect different methods of feeding
the young: in Red-throated Loons, there is spatial separation of female and
male during flights away from the breeding lake to obtain food while in Common
Loons, which fish in the breeding lake, there is almost continuous pair
contact.
*Cinematographer J. Bristol Foster
