On Feb. 9, Peter Kaestner stood in the shadow of majestic Tinuy-an Falls on the Philippine island of Mindanao, on the cusp of a record he’d spent seven decades chasing and worried that he’d arrived too late.
For years, nobody alive had seen and identified more bird species than Kaestner. A retired US diplomat, he is birding’s ultimate “big lister,’’ a star of the small but growing subculture of hypercompetitive bird watchers who scour the world vying to see as many species as possible.
An obsessive birder since childhood, Kaestner woke up that morning in February with 9,997 birds on his personal “life list’’ — more than 90 percent of Earth’s scientifically recognized species and three away from a singular milestone. But he felt hurried. A few weeks earlier, in an essay for the American Birding Association, he had outlined his plans to become the first person to document 10,000 sightings; shortly after, new information forced him to expedite his plans.
“I realized when I was writing it that I was putting a target on my back,’’ Kaestner said from his home in Cockeysville, Md.
He didn’t waste time. Kaestner spent a chunk of January in Taiwan, racking up 15 new bird sightings. Soon, he was in the Philippines, squeezing in an extra trip to the archipelago before another he had planned for March. Working with a local guide, Kaestner needed to see 19 new birds in seven days to reach 10,000. By midafternoon Feb. 9, he had reached 9,999 when they heard an unfamiliar call coming from a nearby heliconia thicket.
When the bird appeared, Kaestner had no doubt about what it was: an orange-tufted spiderhunter, a banana-loving songbird with a sinisterly down-curved bill. Documenting the sighting with a photograph made Kaestner the first birder to reach 10,000 species, a momentous achievement once considered unreachable.
“The number of people that helped over the years was extraordinary,’’ Kaestner said.
Depending on the taxonomic authority, scientists generally agree that there are roughly 11,000 bird species in the world. Fewer than 60 people have ever seen 8,000; fewer than 20 have surpassed 9,000.
Only 271 bird species have ever been recorded at Central Park, a world-renowned birding destination. Only about 750 are found in the US and Canada.
Competitive birding has no official scoreboard. While many birders use photographs and field notes to provide evidence, documentation is largely based on a self-reported honor system. For many years, the preferred platform for Kaestner and other big listers was Surfbirds.com, before the site grew glitchy and unreliable last year. Now they use modern digital platforms such as eBird and iGoTerra. Further complicating matters, the number of accepted species is constantly changing, making lists like Kaestner’s more living organism than stone tablet.
The mega-listing world is small, though, so the big players often know their competition. Kaestner had long considered Philip Rostron, a British birder, his biggest challenger, and Ross Gallardy his heir apparent.
But very few people in that world were aware of Jason Mann, an avid but little-known American birder living overseas who emerged as Kaestner’s chief competitor last year. By that point, Kaestner had his sights set on 10,000, having already broken the world record set by Claes-Göran Cederlund, who died in 2020 but has been posthumously credited with 9,829 sightings.
In January, Mann sent shock waves through the listing world when he updated his total to 9,950 from 9,600, putting him just 50 birds shy of 10,000. His list immediately raised eyebrows. Included were several species either long-presumed extinct or extraordinarily rare, like the New Caledonian nightjar, which had not been verifiably seen since 1939.
Twelve hours before Kaestner found his spiderhunter and announced his achievement online, Mann announced in a since-deleted news release that he had reached 10,000, prompting further — and fervent — online scrutiny.
“Because the two claims came out on the same day, it sort of went viral,’’ Kaestner said. “How in the world could this happen? This thing that has never happened in the history of mankind, that two birders get 10,000 on the same day? It’s crazy.’’
The uproar deeply surprised Mann, who for 40 years had birded the world in anonymity, never identifying as a “lister.’’ He generally kept his records private, since spending time online undercut the foundation of his passions — being outside. In an interview, he said that his bird list was only a fraction of the 20,000-plus species of plants.
Amid the backlash, Mann publicly recognized Kaestner as the record-holder and again turned his list private.