RESUMO
Currently, 52% of all raptor species demonstrate a decreasing population tendency, and the American harpy eagle (Harpia harpyja) has been categorized as "near threatened" by the IUCN. Habitat loss, persecution, and subsequent reduction of genetic diversity are regarded as major threats to the world's strongest eagle. Captive breeding and reintroduction into protected habitats are approaches of species conservation projects, but captive propagation is difficult due to low ex-situ numbers and scarce successful breeding pairs. The aim of the present study was to collect, analyze, and store semen from harpy eagles and to use aliquots for artificial insemination to increase the number of offspring and to include more individuals into the ex-situ gene pool. First, semen collection and semen availability were assessed in four males during the course of 1 year in European zoos. Second, these experiences were transferred to ex-situ breeding programs in Brazilian zoos to attempt semen collection in 13 male eagles. Semen collection was successful in 51.7% of the attempts and in 8/13 males (individual success rates 20-100%) using electro-stimulation. Most commonly, whey-like to milky, whitish semen samples were collected, regularly containing urate impurities (67.7%). The median semen volume was 106 µl and the median sperm concentration 5,000 sperm/µl (750-22,500 sperm/µl). Mean values for pH were 6.7, for sperm motility 27.7 ± 22.6%, for progressive motility 2.9 ± 5.6%, and for sperm viability 46.6 ± 16.3%. Using semen extenders, a sperm motility of 8% was maintained for 27 h in the refrigerator. Artificial insemination was performed in one female, but the success of fertilization could not be assessed due to egg destruction. In this study, methods for assisted reproduction were refined for use in harpy eagles, and the first semen samples were evaluated as a start to establish species-specific orientation values.