Birdathon 2018 Birdathon Big Day 2017 winners! Team Grousing Twitchers (Dave Benson & John Ellis; not pictured Lars Benson & David Steininger) 2018 Birdathon details coming soon! Dates in May 2018 TBD and planning on some exciting changes/additions! The 2017 Birdathon was held on May 20, 2017. Download the 2017 Birdathon Summary and the Species List.