Birdathon is a friendly competition to see which team can identify the most species of birds in a 24-hour period. Modeled on the Global Big Day of Birding which is May 10 this year, Birdathon is similar to a walk-a-thon, but instead of miles, you pledge for each bird species identified. But we give you the first two weeks of May to pick the best day for you. This event also serves as our spring bird count, adding to the longitudinal data we have been collecting.