Big Year and Big Day: the Traditions Behind Competitive Birding
Competitive birding is as old as field ornithology itself. The impulse to count — to see more species than anyone else, in less time, across more ground — has produced some of the most obsessive travel itineraries in natural history. A Big Year, in its simplest definition, is an attempt to record as many bird species as possible within a calendar year, usually within a defined geographic area. A Big Day compresses that ambition into a single sunrise-to-sunrise period. Both traditions have generated records, rivalries, and a culture of logistical planning that would be at home in competitive athletics.
The origins of the Big Year
The North American Big Year tradition traces informally to the 1930s, when early Audubon members began comparing annual lists. The first widely documented serious attempt was Guy Emerson's 497-species year in 1939. Roger Tory Peterson and James Fisher's 1953 cross-continental tour, documented in "Wild America," set an early benchmark of 572 species. The real arms race began in the 1970s with Kenn Kaufman's legendary shoestring year — hitchhiking across the continent as a teenager — and accelerated through the 1990s and 2000s as cheap flights, eBird data, and mobile communication transformed logistics.
The current American Birding Association (ABA) area record is held by John Weigel, who tallied 840 species in 2019 using aggressive travel between Alaska, Hawaii, California, Texas, and Florida — the four corners of North American diversity.
How a Big Year is structured
A North American Big Year typically runs January 1 through December 31 within the ABA area, which includes the contiguous 48 states, Alaska, Hawaii, and Canada. There is no central governing body, no entry fee, and no prize. Records are self-reported, compared against eBird data, and ratified socially within the birding community. The honor system works because the community is small enough that implausible claims are quickly questioned.
A serious Big Year contestant builds a decision matrix by December of the preceding year: which target species require which states, which months are optimal for each region, how to stack multiple targets in a single trip. The Texas coast in April, Alaska in June, California's Farallon Islands pelagic trips in September, and southern Texas's October hawk migration are fixed landmarks in the calendar. The goal is to never travel without picking up multiple new species.
The Big Day format
A Big Day is a 24-hour count, typically run by a team of two to four birders. Teams plan routes months in advance, identifying productive sites within driving distance that can be visited sequentially from midnight through the following night. The World Series of Birding, held annually in New Jersey since 1984, is the longest-running formal Big Day event; teams raise conservation pledges per species and compete for the highest count within New Jersey.
The 24-hour format rewards local knowledge above all else. A well-coordinated team on home ground outperforms a team with better individual skills who does not know the local patch network. Pre-dawn owl spots, a coastal shorebird roost accessible at first light, a hawk watch platform for midday, a productive marsh for afternoon rails, and a nocturnal owl walk to close the day — these are the set pieces of a well-planned run.
Global Big Year attempts
The global Big Year, covering all species worldwide, is a different proposition: a multi-continent endurance exercise that requires both financial resources and extraordinary planning. The current world record, set by Arjan Dwarshuis in 2016, stands at 6,852 species — roughly 64 percent of all described bird species. The attempt ran from January to December and crossed more than 40 countries, relying on the global network of local guides and eBird hotspot data to maximize efficiency.
Global Big Year records have accelerated rapidly as eBird data density has increased. What required months of correspondence and local contacts in the 1990s can now be assembled from hotspot frequency graphs and recent rare-bird alerts. Dwarshuis's record replaced Noah Strycker's 2015 mark of 6,042 species — itself a record that had stood for only a year.
Big Day records and team dynamics
The world 24-hour Big Day record is held by a team running in Colombia, which regularly produces the highest single-day counts anywhere on earth. Colombia's combination of proximity to the equator, extreme altitudinal variation, and Caribbean-to-Amazon span means that a well-positioned team with a vehicle and good logistics can encounter more species in a single county than most temperate countries hold in total. Teams have exceeded 300 species in a single Colombian day.
In North America, a 200-species Big Day in the right Texan county in May is achievable but demands military precision: timing each location to catch the maximum activity window, accounting for travel time between sites, and managing weather contingencies without losing the dawn chorus.
Christmas Bird Count and the citizen science angle
The Christmas Bird Count (CBC), organized annually by the National Audubon Society since 1900, is the world's oldest citizen science survey and the mass-participation equivalent of competitive Big Day listing. Each CBC covers a 15-mile diameter circle on a single day between mid-December and early January. The resulting century-plus dataset is one of the most important long-term records of North American bird populations. The CBC's tradition of friendly competition between count circles has served as a gateway into organized birding for generations of participants.
The ethical dimension
Critics of competitive listing argue that the pursuit of numbers drives poor behaviour: playing recordings to flush skulking species, trespassing to add private-land birds, or disturbing nesting birds for a photograph. Responsible Big Year and Big Day veterans are clear that none of these practices are acceptable, and most serious listers are outspoken conservationists. The sport's reliance on habitat integrity — a drained wetland does not produce rails, a clearcut forest does not produce warblers — gives listers a direct stake in conservation outcomes.
Kenn Kaufman's "Kingbird Highway," his account of the 1973 shoestring Big Year, remains the best single introduction to the tradition: honest about the obsession, clear about the ethical framework, and generous about the community that makes it possible.
How to plan your first Big Day
A Big Day — finding and identifying as many bird species as possible within a single calendar day — is the most efficient field exercise for accelerating bird identification skills, site knowledge, and species list building in a specific region. Unlike a Big Year, which requires year-round effort and typically significant travel, a Big Day can be organized in a familiar area using existing site knowledge and produces a day-long fully documented species list useful for eBird analysis.
The key planning elements for a productive Big Day are: assembling a team of complementary skills (one strong on owls, one on habitat-specialist warblers, one strong on shorebirds), defining the geographic area to be covered, mapping the day's route to minimize dead time between productive sites, and predetermining the order of habitat types based on timing (nocturnal birds at dawn, early morning forest chorus, mid-morning open-country scanning, wetland afternoon when herons and terns are active, late afternoon raptor scanning, dusk owling).
Team composition matters because different birders have different strengths. An experienced owl caller who can attract Screech-Owls and Great Horned Owls (Bubo virginianus) in the pre-dawn hour adds species in the first 90 minutes that would otherwise require separate nocturnal trips. A shorebird specialist adds species in the wader flocks that a generalist team would overlook. The cross-skill team typically outperforms a same-skill team even when the generalist birders are more experienced.
The most common mistake in first-year Big Days is ambitious routing that leaves insufficient time for productive sites. Three excellent sites covered thoroughly produce higher species totals than ten sites covered superficially. The eBird species accumulation curve for a well-known Big Day route (available by looking at the highest-count eBird lists from a given region and date) shows when the incremental return per unit time drops below a threshold that justifies moving to the next site.
The World Series of Birding model, where teams are publicly sponsored and raise conservation funds, provides the template for local Big Day fundraisers. Most regional bird observatories and ornithological societies host annual sponsored Big Day events with route documentation and results published afterwards.