Birds choose long-term partners years before breeding

摘要: Pair bonds can provide social benefits to long-term monogamous species alongside their for reproduction. However, little is known about when these form, in particular how long they are present before breeding. Previous studies of pair formation birds have been rather data-limited, but many migratory report on the wintering grounds. We first systematic investigation prebreeding association patterns pairs by examining entire life histories based tracking data whooping cranes, Grus americana. found that a substantial portion (62%) breeding started associating at least 12 months breeding, with 16 58 beginning associate over 2 years For most pairs, associations future partners also became unique and distinguishable from nonpartner individuals In addition, 60% began one partner had reached nominal sexual maturity. Most late spring upon arrival summer grounds, while other times year were rare. Patterns prior point potential relationships, instance providing support competitive interactions or increasing familiarity.