Studying individual interactions and direct fitness benefits in wild birds: history and practice.
Berg
Elena C
EC
Harvard University, Cambridge, MA, USA. berg2@fas.harvard.edu
Williams
Dean A
DA
D000533:Altruism; D000818:Animals; D001522:Behavior, Animal; D001717:Birds; D003299:Cooperative Behavior; D004463:Ecology; D006379:Helping Behavior; D012098:Reproduction; D012726:Sexual Behavior, Animal