Note: Birding days are a measure of the number of checklists submitted to the bird observation platform eBird by a unique observer. Source: Analysis of eBird data from a research paper currently under review by Natalia Ocampo-Peñuela, Sam de Alfaro, Luca de Alfaro, Katarina Bjegovic, Montague H. C. Neate-Clegg, and R. Scott Winton.