I was surprised too. Are we assuming that there's some correlation between languages and bird species? Or we're just overestimating the power of birds of paradise?
I mean there kinda is. Papua New Guinea has a ton of languages because it has a ton of tribes, most of which I’m guessing are separated/different bc most of the island is dense rainforest. Couple that with the fact that it’s next to megadiverse Indonesia and it’s not a far stretch. (I mean their flag literally has a Reggiana Bird of Paradise)
Interesting case based on the source. If you add French Guiana, France, Reunion and New Caledonia, the totality would be more than enough for France to make this list. There is no caveat excluding territories to begin with and French Guiana is even considered an integral part of the country in any case. Not an expert so there might be a small overlap regarding the species, but not enough to disqualify France.
I tried Madagascar. As it turns out, the source lists it as having fewer species than Luxembourg! Surely that's an undercount, based on a shortage of research.
I ended up searching for a final African or south Asian country, but nope, Bolivia.
I too was surprised no PNG gicen it shares the island of New Guinea with Indonesia