HealthDay News - Birds don't become sick when exposed to the H1N1 influenza strains that caused the 1918 and 2009 global flu pandemics, a finding that suggests birds played no role in the spread of the pandemic-causing viruses, according to a new study.http://news.yahoo.com/s/hsn/20100120/hl_hsn/norolefoundforbirdsinswineflupandemic