The Final Stretch

Planning My Way to 10,000 Birds

by Peter Kaestner

January 9, 2024

EDITOR’S NOTE: Because of the inherent delays of print publishing and the author’s own fast-paced birding, some of the upcoming trips he describes in this article have already been taken, quite successfully! The ABA wishes Peter tremendous luck as he closes the gap to the once inconceivable life list goal of 10,000 birds!

Sometime in the second half of 2024, I hope to see a bird. But this one will be different than other birds, although the bird will not know that. This particular bird will belong to a species that I will not have seen before, and it will be the first new species that I will have seen after my 9,999th. In other words, it will represent my 10,000th species.

A lifetime quest will be finally fulfilled, 64 years of international birding realized. What will the unsuspecting bird be? Where will I see it, and when? Who will experience the milestone with me? This article discusses my plan for reaching this milestone and the factors that influence the road ahead.

I love numbers, especially round numbers. If the volume of my radio lands on a prime number, I’ll change it. When my car odometer turns over to 100,000 or some other wonderful number, I’ll snap a photo, and tell my long-enduring wife. I don’t know how my obsession with numbers evolved, but it developed in parallel with my passion with birds. Listing, and its concomitant competition, has been an integral part of my birding experience. Some of my earliest memories are of comparing lists with my brothers, and twitching rarities.

When attending Cornell University in the 1970s, I was an assistant for Dr. Tom Cade’s ornithology course, teaching the world’s bird families. At that time, I figured I would have neither the time nor the money to compete with the top world birders, some of whom had seen over 4,000 species! (My life list was 962 at the time.) So, I decided to try to be the first to see all the bird families, which I accomplished in 1986.

After a stint in the Peace Corps, I decided to enter the U.S. Foreign Service. The latter decision turned out to be a perfect fit for me. For 36 years, I lived around the world, racking up over 8,600 species along the way. (I also did alright as a diplomat, retiring at the rank of Minister-Counselor, the diplomatic equivalent of a two-star general/admiral.) About 10 years after I graduated, I met and married Kimberly, which completed my preparation for success. Kimberly has been unswervingly supportive of my birding passion. Without my family’s full backing, I would never be in the position I am today.

After retiring from the U.S. Department of State in 2016, I upped my birding and now, after seven years, I can finally see the light at the end of the tunnel. As I write this, my IOC World Bird List total is 9,943. As this issue of Birding goes to press, I have seen 9,942 species, which should not change before the magazine arrives in member mailboxes.

In Aug. and Sept. 2023, Peter Kaestner completed a trip to Sumatra in Indonesia, where he found the spectacular Sumatran Ground-Cuckoo, a bird lost to science for many decades and only formally recognized as a species in 2000. This was his first member of the genus Carpococcyx, a genus with three species which had evaded him. Photo by © Peter Kaestner.

The worldwide competition for the biggest list is an odd phenomenon. I liken it to a race in the dark. You can’t see the route and you can’t see the other racers. By this, I mean that each birder has his or her own standards, not the least of which is whether to count heard birds. I knew a top world lister who counted birds he had mist-netted! But that really doesn’t matter—as the ABA proclaims, there are “a million ways to bird.” As far as knowing the others in the race, there is no agreed-upon organization that vets and publishes listers’ totals. The closest is, which tracks the most complete list of world listers. But there could be someone out there who has more birds than anyone else, and that person could even be over 10,000.

Part of the uncertainty surrounding the world listing competition is how many birds are possible to list. The first single-volume world checklist came out in the early 1970s, and was soon followed by several others, including Jim Clements’. On Surfbirds, world listers usually use either the IOC list or the eBird/Clements list. The IOC list evolved from an effort undertaken by the International Ornithological Committee (IOC), which evolved into the International Ornithologists’ Union (IOU). For me, today, the IOC list contains 189 more species compared to eBird/Clements, which is why it is the preferred list for most world listers. Because I am a committed eBirder, I always use eBird in the field and then transfer my eBird sightings into another website,, where I display my sightings using the IOC taxonomy.

The good news is the IOU has established a working group on avian checklists that is currently harmonizing three of the four world checklists. (The governing foundation of the Howard and Moore Complete Checklist of the Birds does not allow it to participate.) This means that eBird/Clements and IOC checklists will soon recognize the same species. According to the working group, they hope to publish their list in Sept./Oct. 2024. As I approach 10,000, the timing of this work is critical.

The best-case scenario is that there are not too many changes in the new, harmonized list. On the flip side, however, there are two less-favorable outcomes. One unfortunate outcome would be if the new list increased so much from split species that my total leapfrogged over 10,000 while I was home in my armchair. That would not be very satisfying after waiting so long to experience my 10,000th bird. The other difficult outcome would be if the harmonization effort resulted in a reduction of the number of species so that my newly achieved total of 10,000 was lowered so much that I had to do it again, or that the number was significantly reduced through species lumps so as to make the road to 10,000 that much more difficult. In any case, I’ll just deal with whatever happens.

While in Indonesia in Aug. and Sept. 2023, Peter Kaestner added the recently described Meratus Blue Flycatcher, the Meratus White-eye, and the rediscovered Black-browed Babbler to his life list. Photos by © Peter Kaestner.

How did I get here? When I was in university in the early 1970s, the world list was around 8,600. For example, there were then 12 Scytalopus tapaculos recognized and today there are 49 of these sneaky little sprites. While this is an extreme example of splitting and new species, it does reflect a process that has increased the world list of birds by more than 2,000 species in my lifetime. Phoebe Snetsinger, the greatest world birder at the time of her death in 1999, saw this happening and suggested that a percentage of the total list would be a way of comparing birders of different eras. She suggested 90% as an upper limit for a lifetime of birding, as she both overestimated the plight of birds and underestimated the advances in birding that would make birds easier to find. Phoebe passed away in a vehicle accident at 68 years of age after she had seen 84.1% of the world’s birds. Her posthumous listing analysis, “Birding Planet Earth,” is available in the Birding archives, Birding 2000, vol. 32, no. 1, p. 50–55.

Now there are over 11,000 species recognized, and the rate of increase in the number of species appears to be accelerating. It has been suggested that, when all the splitting is finished, there will be 20,000 species of birds in the world. A lot of the growth in the list comes from historically difficult taxonomic situations, including cryptic species and allopatric populations, which do not fit neatly into the widely used biological species concept. Avian taxonomy has improved by a better understanding of birds, for example by the work of Morton and Phyllis Isler and Bret Whitney, whose classic 1998 paper on the use of vocalizations led to the recognition of dozens of species of antbirds, and by huge advances in genetics, as inherited biochemical markers in the cells of birds can be yardsticks to measure species differences.

Once I retire from world listing, I’ll watch the IOU checklist creep ever higher and see birders reach 10,000 as easily as they get 6,000 today. I just hope I will have seen enough of the different forms along the way to get a good number of armchair ticks in my golden years.

When I reached the milestone of 9,000 birds on Oct. 20, 2018, with Puerto Rican Parrot, I created a plan for the last 1,000 birds. The 17-page document is straightforward, and has been revised many, many times as I delete species I have seen and add granularity. At present, it is a last-130-birds plan, but it is also a template for where I’ll go after 10,000. It is basically a country-by-country listing of the birds I need to see. By listing each species, it is easy to see where I must go and what birds I can expect to see. Some countries (Venezuela, Myanmar, and Iran) are shaded out because I cannot visit them now. I hope that will change.

I am writing this in June 2023, and I will be traveling before this article is published. So, I will start the discussion with the plan as it stands now.

With the present taxonomy, I need 133 birds. Getting to 10,000 will take two things. The first is finding new birds and the second is revisions to the world checklist. The revisions are promulgated in August and January, so I will have to revise my plan at least twice a year. Finding new birds is made easier by iGoTerra. I can produce a list of all the countries with birds I have not yet seen. Today, Indonesia leads the list with 239 species, followed by Brazil (111) and Papua New Guinea (104).

My first planned trip is in Aug. 2023, when I will travel to the Indonesian island of Sumatra for a three-week “remote” tour run by Birdtour Asia. I had visited Sumatra twice when I lived in Kuala Lumpur, but 30 years ago the birds were not known as well, and many birds on the remote Barusan Islands had not yet been elevated to species status. During the trip, I hope to find as many as 20 new species and several future armchair ticks. There are many special targets possible, but none is as special as the Sumatran Ground-Cuckoo. A bird unknown until a few years ago, it is now being seen in foothill forest at Bukit Barisan Selatan National Park. It would be my first Carpococcyx, one of the larger genera I have never seen.

I am also taking advantage of being halfway around the world to pick up a few birds in West Java, and to go on a trip to the Meratus Mountains in Kalimantan, the Indonesian part of Borneo. The main targets there are the recently described Meratus Blue Flycatcher, the Meratus White-Eye, and the rediscovered Black-browed Babbler. Along the way, I should get a couple of other lifers, and add many birds to my Indonesia list that I had seen in the Malaysian part of Borneo. I’m shooting for 1,000 birds in Indonesia one day.

While I’m overseas, there should be another IOC update that will affect my plan. As of June 2023, the proposed taxonomic revisions would result in a net gain of 12 species, from 27 splits and 15 lumps. But I won’t know the final number until the updates are incorporated into the IOC list.

My next trips, in October, are to Brazil, a country in which I worked from 2002 to 2004. The first is a cleanup of the east, where I hope to get a dozen lifers in as many days. I organized the trip through a local bird-tour company, Brazil Birding Experts (, but I will be driving a rental car and using local guides. The highlights of the trip are the Cherry-throated Tanager, which I dipped on in 2002, and the recently rediscovered Blue-eyed Ground Dove. To share costs, I will be traveling with an excellent Maryland birder, Richard Edden.

As the January Birding prepares to go to press, Peter Kaestner has returned from his cleanup trip to Brazil, where he found 32 of his 35 targets. Although the Cherry-throated Tanager eluded him yet again, he successfully connected with the until recently long-lost Blue-eyed Ground Dove, as well as the Rondônia Bushbird (left) and the Rufous Twistwing (right). The Silky-tailed Nightjar was his last life bird of the trip. Photos by © Peter Kaestner.

Immediately after finishing my eastern Brazil cleanup, I’ll be traveling to the west to meet my brother, Hank. We’ll do a two-week trip with Brazilian guide Eduardo Patrial. My goal is to get 20 lifers, though I’ll likely come a little bit short, considering the difficulty of many of my rainforest targets. Interestingly, when I lived in Brasilia, I visited Rondônia, observing the 2002 presidential election, but I had little time to go birding. Since then, many new species have been described and much more is known about the birds of this area. Highlight birds I hope to see are Purus Jacamar, White-throated Jacamar, Black-faced Cotinga, and Rondônia Bushbird.

After this, I’ll have a four-month travel hiatus, during which I hope my wife and I will move into our new home on the eastern shore of Maryland. During the pause, an update to the IOC list will be published in January, the results of which will guide my plan for the rest of the year. For example, should my IOC list increase by 20 birds, I might have to reduce my travel schedule. On the other hand, if there are a load of lumps, I will consider adding another destination.

My next trip will be in Mar. 2024, when I will lead a Rockjumper Birding Tours trip to the Philippines. The three-week main tour will cover Luzon, Palawan, and Mindanao, including a couple spots I have not visited in my four previous visits to the archipelago. One locale, Bislig, holds a dozen likely lifers for me. The rest of the tour could yield another 10, so that I could get over 20 for the month. There are a lot of endemic birds in the Philippines! Two of my most-wanted birds will be the Celestial Monarch and the Philippine Eagle. I dipped on the Monkey-eating Eagle, as it was known then, in 1982, when I hiked up Mount Apo. After the main tour, I will lead an extension to the Visayan Islands, but the only possible lifers there, Yellow-faced Flameback and Visayan Rhabdornis, are unlikely.

In late May 2024, I plan to return to Asia, but this time to Japan and Taiwan. This trip has two destinations, and the final itinerary will depend on the number of lifers I gain in the two IOC taxonomic updates of Aug. 2023 and Jan. 2024. As of June 2023, I could get 12 lifers in Japan and 18 in Taiwan. I’ve been to Japan twice, but I never visited the Ryukyu Islands, where most of my potential lifers reside. My most-wanted birds include Lidth’s Jay, Okinawa Rail, and Amami Woodcock.

In addition to a bunch of endemic birds, there is great diving in the Ryukyus. One of the most northern coral reefs in the world harbors one of the most diverse assemblages of butterflyfish. Some of the reefs have 17 species of butterflyfish, several of which would be new for me. Diving is an activity that Kimberly and I share, and I’m always looking for opportunities to enjoy nature together. I love to travel with her, as it makes the trip much more fun. We did a fantastic trip through Micronesia in 2018, filled with beautiful islands, great birds, and incomparable diving.

The author, Peter Kaestner (left), began birding because of his older brother, Hank (right), and they have enjoyed many birding adventures together around the world. Their favorite way to celebrate a life bird is with ice cream. Photo by © Peter Kaestner.

My return to Taiwan would come some 38 years after I visited the island for work in Aug. 1986. My trip was marred by Typhoon Wayne, the longest-lasting cyclonic system in the western Pacific Ocean, which affected the island on both my birding weekends. Because of the torrential rain, I missed several endemic species, including both Mikado and Swinhoe’s pheasants, and Taiwan Blue-Magpie and Yellow Tit. Besides these dips, my wants list includes several species split in the past 40 years.

The final step in the plan is simple: I would like to reach 10,000 in such a way that I can share the experience with my loved ones and others who helped me over the years. Right now, there are a dozen birds I need to see in the Caribbean. Since they are on islands, and each bird is relatively easy to get on its island, I can plan the last 10 or so down to the bird to get exactly to 9,999. I even have a relatively easy Lower 48 bird that could be #10,000 if I play my cards right.

That dream bird would be Tufted Puffin in Oregon. I’ve got my fingers crossed.



Peter Kaestner is a retired U.S. diplomat and currently holds the world’s largest life list. He was the first person to see all the world’s bird families, and, in 1989, he introduced Western science to the bird that would later be called Cundinamarca Antpitta. When not adding to his life list, Peter is a part-time tour leader for Rockjumper Birding Tours.