I am unsure about this sentence. Does it mean "Why is this bird called". I would underständ a sentence like "Miksi tätä lintua kutsutaan punarintaksi?": Why is this bird called robin redbreast? Could you use "Kuinka (miten) tätä lintua kutsutaan?"?

I don't speak any Finnish, but the English and German versions do definitely mean "How is this bird called?" — NOT "Why is this bird called?" And licitatrix's suggested addition of two words to allow the use of "Why?" is a good one. Since there is no such sentence at Tatoeba just yet, I'll add it in as a separate entry for licitatrix to translate into Finnish.

Well, CK is right; "How is this bird called?" is indeed somewhat awkward English, and I did not advocate for such an English translation. I was just pointing out that the English and German versions are more similar in meaning to any Finnish adverb that means "how" than one that means "why?"

"Does it mean "Why is this bird called"."

In theory yes and no, but in practice no. In addition of being adverb meaning "why", "miksi" is also translative case of pronoun "mikä" (what), so in this case the sentence would mean "What do you call this bird?". The sentence in sense "Why is this bird called" doesn't really mean anything, does it? :)

"Could you use "Kuinka (miten) tätä lintua kutsutaan?"?"
Nope, it means different thing also in Finnish, just like CK described.

Argh, Finnish morphology!! Thank you for the answer, Silja. Well, I came close to the answer, when I proposed the sentence with the robin redbreast in the translative...

>"Miksi tätä lintua kutsutaan punarintaksi?"

Melkein oikein! :) Viimeisen sanan taivutuksen pitäisi olla "punarinnaksi".