Mortality of Wintering Ospreys and Other Birds at Aquaculture Facilities in Colombia

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Ospreys (Pandion haliaetus) winter throughout the country of Colombia. Recoveries of banded Ospreys indicate that many are shot in the country with the number increasing since the 1970s. The increased incidence of shooting has coincided with the development of aquaculture facilities in Colom- bia that raise tilapia (Oreochromis spp.). Because these facilities typically lose production to birds such as Ospreys that depredate fish, we conducted a survey of 83 facilities in three states or departments in Colombia in 2001 to determine the species of birds that take fish at aquaculture facilities and the numbers that are killed each year. Our results showed that bird depredation occurs at aquaculture facilities throughout the country, but mostly in the southern portion of the country in the department of Huila. Facility managers reported shooting Ospreys in all three departments with as few as five individuals shot annually in Antioquia in northern Colombia to as many as 270 shot annually in Huila. In addition, facility managers reported shooting nine other species of birds including Green Kingfishers (Chloroceryle americana), Great Kiskadees (Pitangus sulphuratus), Snowy Egrets (Egretta thula), Great Egrets (Casmerodius allms), Olivaceous Cormorants (Phalacrocorax olivaceus), Black-crowned Night-Herons (Nyc- ticorax nycticorax), White-necked Herons (Ardea cocoi), Cattle Egrets (Bubulcus ibis), and Striated Herons (Butorides striatus), for a total estimate of >9000 birds shot in the three departments annually. A number of alternative methods to shooting had been used to reduce losses to birds including the installation of netting, overhead wires, scarecrows, and noise making devices, but, neither these methods nor shooting, were effective in deterring avian predators.

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