speculative in nature. Fish is the Brazilian merganser's main food, and they also eat molluscs, insects and their larvae. The birds, usually in pairs, capture fish by diving in river rapids and backwater. Population The merganser population is believed to have less than 250 birds. Originally, the duck's geographical distribution comprised central-south Brazil and adjacent regions in Paraguay and Argentina. Currently, all confirmed populations are located in Brazil and a more recent population in Argentina and information on most populations is very scarce. The Brazilian merganser population in the Serra da Canastra region is the most significant and best known, with populations occurring hundreds of kilometers away from each other. There are 47 individuals—28 adults and 19 young—in the Serra de Canastra region as of 2006. Most mergansers are found in the Serra da Canastra National Park. 70 birds have been seen near the park's headquarters in rio São Francisco. In Jalapão region are estimated 13 individuals in Novo river on 2009/2010 (four couples and some solitary adults). In 2002, the species was also found on the Arroyo Uruzu in Misiones, Argentina, the first record in the country for ten years, despite extensive surveys done by local researchers conducted throughout previous years. The bird was last reported seen in 1984 in Paraguay, where very little habitat remains; however some local reports show that a few individuals may still be living in the area. Habitat The slender Brazilian mergansers live in low densities in remote and mountainous regions where it inhabits clean rivers and streams with river rapids and riparian vegetation. Brazilian mergansers are very territorial birds defending large stretches of river and the land surrounding the fast-flowing water. They are recognized as a resident species that does not abandon the watercourses where it established its territory. They do not move or want to move once their habitats have disappeared. The birds need large territories and their habitat is fast dwindling. Threat The Brazilian mergansers are very sensitive to habitat degradation and loss primarily due to human actions. A major threat to the birds' survival is the issue of silting of rivers caused by the expansion of farming activities, mining, watershed degradation and soil erosion, as well as deforestation. Current traditional soil management and use practices in the region from farming may bring about serious damage regarding conservation of natural resources, especially water, on which the Brazilian mergansers and the farmers