(noun) A birding competition or personal goal to positively identify as many different bird species as possible in a single 24-hour period. Big days can be popular guided field trips for birding festivals, or birding organizations may promote big days as service project fundraisers or competitions to raise awareness of local birding opportunities or bird conservation.
Birders can do a big day individually, but they are equally common for groups of birders since more individuals watching and listening for birds can increase the number of species seen. While most big day records rely on birds that have been identified by sight, birding by ear is equally valid for most records. If the big day event is part of an organized competition, there may be restrictions set on how birds can be recorded, what geographic boundaries (within a state or county, for example) are allowed or how the bids must be identified.
Planning a big day requires attention to detail to determine the best route through the day that will visit the widest variety of habitats during their most productive birding hours. Birders who may be planning a competitive big day can often scout the local area before the designated day and may also keep abreast of rare bird sightings and nearby vagrants in order to add to the list. Owling is also a part of many big day plans in order to include additional species during nighttime hours.
See also: Big Year
Photo – Northern Lapwing © Ferran Pestaña