Is the gene pool of influenza viruses in shorebirds and gulls different from that in wild ducks?

Evidence is presented for a second major gene pool of influenza A viruses in nature. Shorebirds and gulls harbor influenza viruses when sampled in the spring and fall. Approximately half of the viruses isolated have the potential to infect ducks but the remainder do not. The hemagglutinin subtypes that are prevalent in wild ducks were rare or absent in shorebirds and gulls.