Fitness consequences of long-term pair bonds in barnacle geese: monogamy in the extreme

• Main Author: Jeffrey M. Black
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Branta leucopsis
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.494.1428; http://www.bg.fcen.uba.ar/eyca/Seminarios2/Seminario23.pdf

In barnacle geese Branta leucopsis, pair-bond members generally remain together every day, each year, often for life. Geese that maintain long-lasting pair bonds during their lifetime produce more offspring than those with shorter pair durations. This result was shown while statistically controlling for the birds ’ life span and the proportion of life spent without a partner, two variables that also influence lifetime reproductive success. I argue that continuous partnerships are maintained in highly com-petitive goose societies because of the constant need for female–male cooperation, without which acquiring adequate resources for reproduction would be prohibitive for both sexes. Key words: barnacle geese, Branta leucopsis, cooperation, monogamy, lifetime reproductive success, mate familiarity, mate fidelity, pair bonds, partnerships, site fidelity. [Behav Ecol 12:640–645 (2001)] Perennial monogamy, defined as the annual reestablish-ment or continuous maintenance of pair bonds, occurs in a variety of animals. This extreme form of social monogamy is common in birds, occurring in at least 50 % of the 28 orders and 21 % of the 159 avian families (Black, 1996). Describing the adaptive significance of long-term pair bonds is a difficult task because it requires researchers to track the social status and fate of individuals over entire lifetimes.