- Who
- Dušan Brinkhuizen, Rudy Gelis, Mitch Lysinger, Tuomas Seimola
- What
- 431 total number
- Where
- Ecuador ()
- When
The most bird species spotted in a 24-hour period (known as a "Big Day" bird count) by a team is 431 by professional guides Dušan Brinkhuizen, Rudy Gelis (both Netherlands), Mitch Lysinger (USA) and Tuomas Seimola (Finland) in Ecuador on 8 October 2015.
Among birders, a "Big Day" is a team effort to identify as many bird species as possible during a single calendar day, and to strive to have all team members identify all the species recorded. As with most aspects of birding, accumulating a list of species seen or heard fundamentally depends on an honour system. Whether birding only casually for an hour or two, or participating in officially sanctioned birding competitions, experienced birders recognize that it is vital to tally only those species that they identify positively and without doubt. To encourage adherence to the honour system, and to standardize practices that ensure comparability among birding practices of different teams, the American Birding Association has developed official rules by which an officially registered Big Day Count must be conducted. Among these rules is the stipulation that the ratio between the fully “shared” total number of species detected (i.e., species identified by every member of the group) and the grand total reported by the group must be equal to or greater than 95%. Other rules (a) restrict the allowable distance among group members to within direct-voice contact, (b) require that all group members travel in the same vehicle, and (c) prohibit purposely gaining information about the location or identification of species from individuals outside the group during the Big Day itself.
The world’s first famous "Big Day" record was set by the late ornithologists Ted Parker and Scott Robinson on 30 September 1982 in Madre de Dios, south-east Peru. With no use of motorized transportation (they travelled by foot and canoe), Parker and Robinson identified 331 bird species. This record stood until 30 November 1986 when Terry Stevenson, John Fanshawe and Andy Roberts performed a 24-hour count in Kenya. Their team used two aeroplanes, among other vehicles, and resulted in 342 bird species logged. More recently, a Louisiana State University team comprising Dan Lane, Mike Harvey, Glen Seeholzer and Fernando Angulo tallied 354 species, also in Peru, on 14 October 2014.
