A comparison of sex determination methods for the Chilean Flamingo (Phoenicopterus chilensis)

In the flamingos of the genus Phoenicopterus, sexual dimorphism is limited to the slightly larger size of the males, making it difficult to determine the sex of the individuals by direct observation. During a routine veterinary check at Fundación Temaikèn, five morphometric variables were measured: body mass (gr), culmen length, tarsus, middle finger and flat wing (mm), and blood or feather samples were obtained from 66 adult Chilean Flamingo (Phoenicopterus chilensis). Chelex 100 was used for DNA purification and three primers (P2, P8 and P0) were used for the amplification of sex-specific bands. Males were significantly larger than females for all variables under study except the culmen length. Based on the DNA-determined sexes, we used discriminant analysis (DFA) to create equations for determining sex. The obtained functions allowed to correctly classify 78.8% of the individuals studied. Although DFA produced significant discriminant functions for correct sex assignment, the correct classification percentage was low indicating that the use of morphometric measures is not a reliable method for determining the sex of this species. According to these results, DNA-based techniques allow the unequivocal sex determination in these birds with scarce sexual dimorphism. In this work we demonstrate the efficacy of molecular analysis from feathers, a type of sample that can be easily obtained, minimizing the manipulation time of the animals. Feathers do not require special storage conditions, which can facilitate the collection of samples in field campaigns at remote sites.