The first information on the morphometry and sexual size dimorphism of the sympatric South American (Sterna hirundinacea), Cayenne (Thalasseus sandvicensis eurygnathus) and Royal (T. maximus maximus) terns from the Patagonia region in Argentina is provided, and a discriminant analysis to sex the three species is used. Morphological characters were obtained from South American Terns (n = 83), Cayenne Terns (n = 63) and Royal Terns (n = 20). All species were sexed using polymerase chain reaction-based molecular techniques. Sexes in the three tern species were only slightly dimorphic in size. Male Cayenne and South American terns were significantly larger than females in bill length, bill depth and head length. Royal Terns, in contrast, showed a high overlap in most morphological measurements, with head length being the only measurement that differed significantly between sexes. Head length correctly sexed 89% of South American Terns and 75% of Royal Terns, while a function including bill depth and head length correctly sexed 78% of Cayenne Terns. Our results provide a valuable tool for rapid sexing in the field of these three Patagonian terns, although reliable sexing in Cayenne and Royal terns should be preferentially achieved using a combination of morphometric and molecular sexing.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 37 • No. 2