Trumpeter swan which is apparent even when the swan is not standing or swimming upright) and larger, wedge-shaped bill as compared to the tundra swan. Trumpeter swans have similar calls to whooper swans and Bewick's swans. They are loud and somewhat musical creatures, with their cry sounding similar to a trumpet, which gave the bird its name. Beginning in 1968, repeated in 1975, and then conducted at 5-year intervals, a cooperative pan-continental survey of trumpeter swans was last conducted in 2015. The survey assesses trumpeter swan abundance and productivity throughout the entire breeding ranges of the three recognized North American populations: the
Pale-winged trumpeter species, the ochre-winged trumpeter ("P. ochroptera"). The reproductive behavior of the nominate subspecies of the pale-winged trumpeter is the best known of all the trumpeters'. Groups of adults defend a territory together. Several males mate with the dominant female, the dominant male doing so most often. She lays an average of three eggs in a hole in a tree, where both males and females incubate. The young hatch covered with thick, dark, cryptically patterned down. Soon afterwards, they jump down to the ground and follow the adults. Their call is a loud staccato trumpeting. Pale-winged trumpeter The pale-winged trumpeter ("Psophia