Breeding Cranes are generally monogamous.
Mated birds stay together throughout the year, and typically remain paired until one bird dies.
The age of sexual maturity has seldom been studied in wild cranes, but individuals in most species probably begin to establish pairs in their second or third years. Pair bonds form within flocks of non-breeding birds, or outside of the breeding season within mixed flocks. Many, if not most, pairs fail to breed successfully in their initial attempts. A strong pair bond is maintained as long as the pair successfully reproduces. However, if breeding efforts continually fail, the pair bond weakens and new mates are eventually taken.