title: Evolutionary biology. Hybrid costs avoided.
authors.forename: D
authors.initials: D
authors.lastname: Hasselquist
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005260:Female; D005298:Fertility; D006824:Hybridization, Genetic; D008297:Male; D020308:Songbirds / Q000235:genetics / Q000502:physiology*; D013045:Species Specificity