As the sun sets behind Colombia's Andes Mountains, thousands of North American ospreys make their way to roost in trees growing along the Magdalena River. The migrating birds are drawn to this place because of what lies below-a fish farm, one of about 600 farms throughout the country. Of course, these fish farms are not intended to serve as feeding grounds for hungry ospreys. The farms are part of a burgeoning industry. The fish are a "cash crop," which is sold to both domestic and foreign markets. As a result, the fish-eating ospreys are at odds with farmers trying to protect their source of income. And so, the battle ensues and the losses are high.

Research funded by the USFWS Wildlife Without Borders Program indicates as many as 14,000 ospreys are killed by fish farmers each year within the 7 Latin American countries surveyed. When these findings are applied to the 21 Latin American and Caribbean countries that have fish farms along the birds' migratory route, the actual mortality rate for ospreys is most certainly much higher.

One farmer surveyed admitted to shooting about 200 ospreys each year. And, ospreys aren't the only birds being shot. Large numbers of Green kingfishers, common egrets, snowy egrets, great kiskadees, striated herons, cattle egrets and black-crowned night herons are killed as they attempt to feed on this abundant supply of readily available fish.

Osprey kills are highest in southern Colombia where farms specialize in the production of surface-feeding red tilapia, which are raised in large, open impoundments. Fish farms typically are small, family-owned operations consisting of 5 to 10 freshwater ponds. Farmers surveyed said that fish predation by birds like the osprey cost each small farm as much as $350,000 Colombian pesos annually, and large operations can lose several million pesos in profit each year. Colombia's Ministry of the Environment reported a significant economic loss due to fish consumption by birds. Additionally, results show that farm owners spend millions of pesos each year trying a variety of bird deterrents such as noise-making devices, scarecrows, dogs and hired-man patrols. None of these methods has proven to be effective. All of the farm owners surveyed showed concern over their losses to bird predation and wanted to learn more cost-effective methods of discouraging birds from taking fish.

During the research period, Colombia's National Institute for Fisheries and Aquaculture and The Alexander von Humboldt Institute organized a meeting of fish farm operators to discuss the issue of fish losses to bird predation. Researchers who attended the meeting were encouraged by the farmers' interest. Farmers openly shared ideas and designs for deterrents they had tried and found effective.

A few farmers reported successful results after installing overhead lines of nylon twine. These farmers said the overhead lines were inexpensive and seemed to be effective in reducing fish losses without killing birds. Other farmers surveyed, especially those running large scale farms in Ecuador, have been able to decrease fish losses by covering their ponds with nets. The nets seem to be effective as long as they are well maintained.

Since 1998, when an alarming number of wounded birds were brought from fish farms to Colombian rehabilitation facilities, the USFWS Wildlife Without Borders Program has funded two phases of research to document the threat to North American ospreys wintering in Latin American countries. The research clearly shows that the threat is significant. More importantly, the research also shows a heightened interest within Latin American government agencies and among fish farm owners to work together to find ways to solve the problem. It is only through partnerships like these, coupled with collaboration across international borders, that problems such as those encountered by the osprey can be effectively addressed to the benefit of both birds and humans alike.