Voice - Their pre-historic sounds are often heard as large flocks of cranes, migrating northward to their breeding grounds, pass high overhead. The calls also form part of their courtship dance on the roosting and nesting grounds. They have been described as a rolling, guttural, rattle, "krooo-oo" or "garooo-a-a-a", which is repeated, and can be heard for well over one mile (0.62 kilometers).
