less mobile, resident taxa, but the supporting evidence has often remained circumstantial. One example is the interaction between water birds and benthic feeding fish, or fish that feed at the lowest level of a body of water. Many migratory water birds use similar food resources on their breeding, molting, or overwintering grounds as do resident fish species. Studies, such as that done by Eadie and Keast in 1982, found an inverse relationship between the waterbird Goldeneye and benthic feeding fish across multiple lakes. Diseases Outbreaks of diseases spread by waterbirds result from the transition of water-borne viruses to those wild birds. The spread can be caused by dead waterbirds in the vicinity of other organisms, or simply from waterbirds with the virus settling into more densely populated areas (whether by humans or other organisms). Duck enteritis virus (DEV) Duck plague (DP), also called duck enteritis virus (DEV), presents the most important concern in mass waterfowl production. Free-ranging water birds are the most likely infectious carriers. While the overall epidemiology of DEV is unknown in western Europe, studies conducted in Poland agree with the high levels of transmission between free-ranging water birds. DEV is an aetiological agent of DP, which represents one of the most acute and lethal diseases of waterbirds, and infection can spread easily between farmed and wild waterbirds. Over 48 species of birds, including those not considered waterbirds, are susceptible to infection by DEV, and the mortality rate of this disease can reach up to 100%, especially in young birds. H5N1 Avian influenza caused by infection with H5N1, a highly pathogenic avian influenza virus (HPAIV), has spread in poultry in more than 60 countries in Eurasia and Africa since 1996, when the first outbreak occurred at a goose farm in Guangdong province in China. H5N1 in wild birds have spread to Asia, Europe, and Africa, and it is possible for the H5N1 virus to be spread by migratory water birds to the west and south, as genetically closely related H5N1 viruses have been isolated in several countries since 2005. H5N1 HPAIV infections have become endemic in several countries and cause accidental transmissions to humans. H5N1 viruses are thus now recognized as one of the most likely candidates for the next pandemic. References Birds by common name Birds