Variation in assortative mating in two colonies of Arctic skuas.
D000818:Animals; D001717:Birds / Q000502:physiology*; D001947:Breeding; D005260:Female; D005787:Gene Frequency; D014644:Genetic Variation; D006579:Heterozygote; D008297:Male; D010641:Phenotype; D012641:Selection, Genetic