Sounds and Vocal Behavior

Gull vocalizations are generally understudied, and the Olrog's Gull is no exception. What little is known about its vocalizations comes from a single publication from almost half a century ago (20 Devillers, P. (1977). Observations at a breeding colony of Larus (belcheri) atlanticus. Gerfaut. 67: 22-43. Close ).

Vocal Development

Little information. During observations at a breeding colony, no specific vocalizations of young chicks were noted (20 Devillers, P. (1977). Observations at a breeding colony of Larus (belcheri) atlanticus. Gerfaut. 67: 22-43. Close ). Fully-grown juveniles utter incessantly a high-pitched modulated note kleeeuh.....kleeeuh.... when begging food from adults. Notes are quite variable, but on sonogram typically hat-shaped with longest middle part of note flat-pitched around 4kHz .

Vocal Array

Very few sound recordings are available of this species, and the following is almost entirely based on a brief study at a breeding colony (20 Devillers, P. (1977). Observations at a breeding colony of Larus (belcheri) atlanticus. Gerfaut. 67: 22-43. Close ):

Long call. The Long call is comparable to the Long call of other large Larus gulls. It consists of two or three muffled, drawn-out notes (uttered while the neck and head are bent down, the bill almost between the legs), followed by a series of faster and more run-together notes which progressively slow down (while the neck and head are now stretched forward at an angle of about 45°) and may sometimes end with a few mumbled notes gek-gek as an 'afterthought' (while the bird is now again in a normal position).

Nyaaaah. A drawn-out distinctly nasal note nyaaah which has a duration of 0.4‒0.6s. On sonogram, it is clearly overslurred, the many harmonics are separated by about 700Hz and loudest in the range 1-4kHz.

Gek-gek. A short note, typically uttered in pairs gek-gek....gek-gek... , but also single or tripled bursts may be given. Gek note has a duration of about 0.06s.

Wuuu. A characteristic, loud, emphatic, piercing, high-pitched wuuu!

Caw. A short overslurred nasal note caw or yap with a duration of 0.15‒0.18s, uttered singly and typically repeated a few times at irregular intervals. On sonogram, it is clearly overslurred, the many harmonics are separated by about 700Hz and loudest in the range 1-4kHz.

Geographic Variation

Formerly treated as conspecific with Belcher's Gull (Larus belcheri). The Long call of the latter is structurally similar, but usually has some additional introductory notes (20 Devillers, P. (1977). Observations at a breeding colony of Larus (belcheri) atlanticus. Gerfaut. 67: 22-43. Close ). A detailed comparison of the vocabulary is lacking however. Within present species, geographic variation is unlikely.

Phenology

Outside the breeding season, Olrog's Gull is rather silent, and the Caw note is mostly heard. During the breeding period from September to December the gulls become much more vocal, especially around the breeding colony.

Daily Pattern of Vocalizing

At the breeding colony, birds are vocal throughout the day, and vocal activity is rather determined by any event that may occur, such as alarming for an intruder, uttering territorial signals around the nest etc. Nocturnal activity (94 Yorio, P., F. Quintana, A. Gatto, N. Lisnizer, and N. Suárez (2004) Foraging patterns of breeding Olrog’s Gull at Golfo San Jorge, Argentina. Waterbirds 27:193–199. Close ) suggests birds may also vocalize at night.

Places of Vocalizing

Long call is typically uttered when birds are on the ground, and is accompanied by a specific display posture. Other vocalizations are also uttered in flight, and specifically the wuuu call is exclusively given in flight.

Sex Differences

No specific information. Presumably all vocalizations are uttered by both sexes.

Social Context and Presumed Functions of Vocalizations

The Long call is mainly used around the breeding colony. This advertisement call serves as a territorial signal e.g. when other adults approach nest or chicks too close, and presumably also has a pair bonding function. Two members of a pair often both utter the Long call, and in a breeding colony it is often contagious, invoking response by other pairs. Nyaaaah and gek-gek are mild alarm calls. Whenever an intruder approaches the colony, these calls are uttered, and when danger is becoming imminent the whole colony may utter these vocalizations, resulting in a loud deafening noise. The Wuuu call is a strong alarm call, typically used when a single bird identifies an intruder at close range. An emphatic and prolonged form of this call is delivered by birds vigorously swooping at an intruder. The Caw call is heard away from the colonies, and may be a contact call between congeners.

None reported.