Evidence for Genetic Monogamy But Low Mate Retention in the North American Black Tern (Chlidonias niger surinamensis)

Abstract. Eleven family groups (n = 22 adults, 28 chicks) of North American Black Terns (Chlidonias niger surinamensis) were genotyped at four polymorphic loci in a pilot study to determine the genetic mating system of this socially monogamous species. Samples were collected between 2003 and 2008 at two colony sites in Wisconsin (USA) that differed in structural complexity of the breeding habitat and nest density, and from families in which the adult males (putative fathers) varied with respect to body condition. Thus, both ecological and individual variations were explored as possible factors influencing the extent of extra-pair paternity. No mismatched alleles were detected, however, between chicks and their putative parents, suggesting that extra-pair paternity is negligible in this subspecies. Despite the small sample size, the combined probability of detecting an allelic exclusion at one or more loci was 0.998, indicating sufficient power to detect a case of extra-pair paternity if it occurred. Data ...