Sex identification in birds of prey by ultrasonography

Real-time ultrasonography was used to detect the oviductal structures in 33 birds of prey of seven different species. The oviducts were visualized in unanesthetized birds with an ultrasonographic scanning probe placed into the cloaca. The left oviduct appeared as an elongated hypoechoic structure with sharply demarcated echogenic borders and an inconsistently detectable luminal echo. The morphologic identification and regular topologic localization of the vaginal portion of the avian oviduct was confirmed with correlative dissection of the reproductive tracts. Ultrasonography is atraumatic and accurate and is a valuable procedure for noninvasive gonadal sex diagnosis in monomorphic species of raptors.