How many countries would you have to vist to see all the bird species in the world? (1 Viewer)

[Andy Lakin]

The current Guinness Book of Records says Claes-Goran Cederlund (died 2020 iirc) managed 9761 Sp from 135 countries. That must be a great percentage of the world total. I don't know how many countries don't have any endemics (there must be quite a few) as a total guess I would say not many more countries required than 135. I'm not really interested in logistics/ out of bounds countries/ areas just the total number of countries.

As I type this I realise that it may be a pain to work it out, but I thought that someone may have already had a go at calculating it .

Cheers
Andy

 

[Jeff Hopkins]

Actually, Rockjumper just started a promotion designed to allow you to see all families, but all species? Wow.

 

[01101001]

Unless I'm missing something, you can't really calculate the optimal solution in any reasonable time. The problem could be formulated as such:

(get_species_1) AND (get_species_2) AND ... AND (get_species_n)

which is equivalent to:

(go_to_country_No.1having_species1 OR go_to_country_No.2having_species1 OR ... OR go_to_country_No.k_1having_species1) AND (go_to_country_No.1having_species2 OR go_to_country_No.2having_species2 OR ... OR go_to_country_No.k_2_having_species2) AND ... AND (go_to_country_No.1having_speciesn OR go_to_country_No.2having_speciesn OR ... OR go_to_country_No._k_n_having_speciesn)

Have a look at: Boolean satisfiability problem - Wikipedia. So, it seems to me, you either have to settle on a (possibly) suboptimal solution or show equality in P versus NP problem - Wikipedia. Of course, the latter option would be better because it comes with a bonus million dollars reward that you could later spend on actually getting all these.

 

[chowchilla]

I very much doubt you could come up with an exact figure. Even if you only counted countries that have endemics, or which are the 'best' places to see certain birds, there's no guarantee you'd see everything avian there is. You may well see any given species in less likely places. For me, it took a visit to Taiwan to see Spotted Nutcracker and Alpine Accentor, yet I dare say both are easier elsewhere. Then you have the added complication that the local forms of those species may get split in the future from, say, the European and mainland Asian forms.

You would probably also need to make multiple visits to certain countries and regions within them as you'd miss some birds first time out, and maybe second and third etc, as well as the need to visit different regions within any given countries for local specialities and endemics. Some birds are just very hard to find. You'd have a better idea of where to concentrate your efforts once you're up in the high figures, simply by looking at what's left.

I've guided birders around the Aus Wet Tropics a number of times. I know that you can go to a place that is guaranteed to get you bird X (my bogey always seemed to be Fernwren), and not see it. One of the easiest endemics near Cairns is Grey-headed Robin. It is not uncommon for them to be right at your feet feeding. Just before Covid, I guided someone to Hypipamee, and could we get the Robin? Meanwhile, we had not one but three cassowaries and still no robin. That's birding.

Now, one could presumably work out the minimum number of countries needed to get every species in the world, but it would be hypothetical to say the least for the reasons given.

 

[Farnboro John]

I very much doubt you could come up with an exact figure. Even if you only counted countries that have endemics, or which are the 'best' places to see certain birds, there's no guarantee you'd see everything avian there is. You may well see any given species in less likely places. For me, it took a visit to Taiwan to see Spotted Nutcracker and Alpine Accentor, yet I dare say both are easier elsewhere. Then you have the added complication that the local forms of those species may get split in the future from, say, the European and mainland Asian forms.

You would probably also need to make multiple visits to certain countries and regions within them as you'd miss some birds first time out, and maybe second and third etc, as well as the need to visit sifferent regions within any given countries for local specialities and endemics. Some birds are simple very hard to find. You'd have a better idea of where to concentrate your efforts once you're up in the high figures, simply by looking at what's left.

I've guided birders around the Aus Wet Tropics a number of times. I know that you can go to a place that is guaranteed to get you bird X (my bogey always seemed to be Fernwren), and not see it. One of the easiest endemics near Cairns is Grey-headed Robin. It is not uncommon for them to be right at your feet feeding. Just before Covid, I guided someone to Hypipamee, and could we get the Robin? Meanwhile, we had not one but three cassowaries and still no robin. That's birding.

UK....

John

 

[dantheman]

All the countries except the ones you don't need.

 

[cajanuma]

In addition to visiting all the countries that have single-country endemics, you'd also need to visit a few that don't have any. For instance, there are several dozen species endemic to the Upper Guinea biogeographical area (comprising all or parts of Ghana, Cote d'Ivoire, Liberia, Sierra Leone, and Guinea), but none of those countries have single-country endemics. Also, I'm not sure if any of these countries have all of the Upper Guinea endemics (maybe Liberia or Sierra Leone?) so you'd probably have to visit at least two. I think there are a few other parts of the world, like Central Asia, where the same holds true.

I guess the way to figure this out is to first come up with a list of all the countries that have single-country endemics, which is easy enough, then figure out how many bird species don't occur in any of these countries, which is the hard part...

 

[greer3]

Noah managed to see every species in the world when a pair of every bird species in the entire world made their own way to the Ark for the duration of the great flood. He never had to leave his country of origin.

 

[Farnboro John]

Noah managed to see every species in the world when a pair of every bird species in the entire world made their own way to the Ark for the duration of the great flood. He never had to leave his country of origin.

Since he was technically a Palestinian and the Ark ended up in Turkey we know that isn't so!

John

 

[greer3]

Ah yes, but when every bird species turned up at the Ark before the flood started, he saw a pair of every species of bird at that point, wherever he lived.
Amazing how Noah managed to feed almost 20000 birds for 150 days, meet their very diverse dietary needs, stop the predatory bird killing other birds, AND clean up their poop. Another version in the Bible says it was only 40 days, but it was an amazing feat, to be sure.

 

[THE_FERN]

Unless I'm missing something, you can't really calculate the optimal solution in any reasonable time. The problem could be formulated as such:

which is equivalent to:

Have a look at: Boolean satisfiability problem - Wikipedia. So, it seems to me, you either have to settle on a (possibly) suboptimal solution or show equality in P versus NP problem - Wikipedia. Of course, the latter option would be better because it comes with a bonus million dollars reward that you could later spend on actually getting all these.

Yes but it's bounded by country endemics. You have to visit all countries which have at least one, and the minimum number of countries to see the rest

 

[nartreb]

Unless I'm missing something, you can't really calculate the optimal solution in any reasonable time. The problem could be formulated as such:

which is equivalent to:

Have a look at: Boolean satisfiability problem - Wikipedia. So, it seems to me, you either have to settle on a (possibly) suboptimal solution or show equality in P versus NP problem - Wikipedia. Of course, the latter option would be better because it comes with a bonus million dollars reward that you could later spend on actually getting all these.

The nice thing about NP problems is that checking the correctness of a solution is relatively easy (polynomial time). The complexity of finding a solution doesn't matter in this case; there are only a few hundred countries to consider at most, depending on ones definition of country. with "only" tens of thousands of species, you could brute-force this problem in a day if I'm not mistaken.
For a not-proven-optimal-but-likely-very-close result, I'd go with a greedy algorithm: start with the country with the most species. Cross those species off the list. Add the country with the most remaining species. Repeat until list of species is empty.
The question of finding an optimal route through all those countries is famously NP-Complete, too

 

[01101001]

That could be 2^(all - with_endemics) checks in a naive algorithm minus optimisations; agree with the latter.

 

[James Lowther]

I don’t think this would be too hard to work out.
Principally because I don’t believe there are very many species that occur ONLY in countries that don’t have single country endemics.
There’s a list of those here

Endemic bird species

Endemic species are those known to occur naturally within one country only.

ourworldindata.org

Accuracy can be called into question I guess and it raises the question as to what is a country, and what does it mean for a species to occur naturally in a given country (is a single non-breeding record enough e.g.). But it gives a good first picture.
Add together all the species (endemic and non-endemic) that occur in countries with endemics and I doubt you would have a huge number left over.
The only region of the world that seems to have no single country endemics but could be expected to have a reasonable number of restricted range species is maybe west Africa,
Cheers
James

 

[chowchilla]

I mean, Mayotte and Reunion have endemic species but neither is a country; and I don't think their birds are included on the French list, but on lists of their own. That's the sort of area where it gets tricky.

 

[Rob Hunt]

I mean, Mayotte and Reunion have endemic species but neither is a country; and I don't think their birds are included on the French list, but on lists of their own. That's the sort of area where it gets tricky.

On a similar theme, even to see all the World bird families, it’s necessary to visit both New Caledonia (Kagu) and Puerto Rico (Puerto Rican Tanager), neither of which are countries.

 

[greer3]

Dan Koeppel's book on this subject is well worth a read. It's called, 'To See Every Bird on Earth: A Father, a Son, and a Lifelong Obsession'​

Written by his son, he explains the difficulties his father encountered attempting to see every bird species. I'm no great fan of books about nature, but this one's different, a great read and highly recommended.
Some reviews of the book:
"Marvelous. I loved just about everything about this book."--Simon Winchester, author of The Professor and the Madman

"A lovingly told story . . . helps you understand what moves humans to seek escape in seemingly strange other worlds."--Stefan Fatsis, author of Word Freak

"Everyone has his or her addiction, and birdwatching is the drug of choice for the father of author Dan Koeppel, who writes affectionately but honestly about his father's obsession."--Audubon Magazine (editor's choice)

"As a glimpse into human behavior and family relationships, To See Every Bird on Earth is a rarity: a book about birding that nonbirders will find just as rewarding."--Chicago Tribune

 

[Andy Lakin]

There must be a fair number of European countries without any endemics. Also I wonder if there any historic attempts to see all the world's species back in the day when people with vast amounts of wealth loved challenges like this.That would surely make for a gripping read.

Also roughly how many new species are being described/ accepted every year.

 

[01101001]

The only endemics in Europe (I didn't count the breeding-only seabirds) are found in the Canaries (8), Madeira (3), the Azores (2), the Balearic Islands (1), Corsica (1), Cyprus (1) and Scotland (1).

 

[Farnboro John]

The only endemics in Europe (I didn't count the breeding-only seabirds) are found in the Canaries (8), Madeira (3), the Azores (2), the Balearic Islands (1), Corsica (1), Cyprus (1) and Scotland (1).

John