Big Bird Day is a wonderful celebration of our avian friends through the dedication of an entire day to birdwatching and recording the number of species sighted in a region. The Big Bird Day was initially started by the DelhiBird group (created by Nikhil Devasar and Bikram Grewal) as an informal event held in February or March. The first Big Bird Day was held on February 22, 2004 when 236 species of birds were recorded across Delhi.
Every year since then, self-organised volunteer birders under the guidance of chosen group leader(s) cover the fields and wetlands in and around Delhi from early morning until late in the day to spot bird species. Over the years, the data collected have revealed the changing trends in habitat condition, bird diversity, migration and related ecological issues. The highest number of bird species recorded in a Big Bird Day was 271 in 2005.
In the years since 2004, volunteer birders and members of Delhibird and other groups located outside the capital started their respective Big Bird Day counts. From just a few outstation teams in 2010, there were over 30 teams participating in Big Bird Day counts in 2012, with a few teams pitching in from overseas as well. In 2013, the Big Bird Day went truly national with over 160 teams comprising over 1,000 birders coming together to celebrate the first pan-India Big Bird Day.