MIAMI — Federal scientists have confirmed cases of an infectious avain flu strain in several species of Florida birds, the state announced Tuesday. The Florida Fish and Wildlife Conservation Commission said it is investigating bird mortalities in Brevard, Indian River and Volusia counties that are believed to be caused by “Highly Pathogenic Avian Influenza.” The agency was notified of the presence of the disease by the National Veterinary Services Laboratory, according to an FWC statement released Monday. The species impacted include the lesser scaup, black vulture “and other species,” the FWC…