Bretagnolle and Thibault (1993) distinguished 5 types of calls in this species: Alarm; Solicitation (food-begging); Guard; Excited; Screaming. Female’s calls generally stronger and lower-pitched than those of male, perhaps owing to larger body size.
Guard calls: given by both sexes, a series of slow, whistled notes, falling rapidly in pitch. Given when an intruding Osprey begins to approach caller’s nest or perch, usually at some distance away (0.1–0.3 km). Guard Call may grade into Excited and Screaming calls as intensity of threat increases.
Alarm calls: given by female more than male, when a potential predator (non-Osprey) or disturbance (boat, human, vehicle) approaches nest. Generally given at nest or a perch; also in flight.
Solicitation Call: given only by female, has 3 gradations (low to high); primarily a food-begging call, heard often throughout season in breeding areas.