I recently pulled the eBird dataset into postgresql and decided to look at which day of the year has the most recorded species in Parulidae. Its April 17th. This is for Chambers and Galveston counties that include Anahuac, the Bolivar, and Galveston Island. It turns out calculating warblers-per-minute effort is useless without doing rarefaction. The vast number of lists in April along the coast wash out any signal as you run out of warblers to see pretty quickly.