Why is "talk about" incorrect here? If it really is wrong, how would German say "They talk about white owls"?
That should have been accepted. Report it next time if you haven't already. I would personally prefer the present continuous tense though ("They are talking about white owls").
Thanks. I will. Do you prefer the present continuous because you believe it translates the German better?
The German phrase can, grammatically, be translated as either simple or continuous present. But we should also consider as much context as we have to produce a sentence that sounds as natural as possible. I just think that this phrase is more likely to be said in a present continuous sense. "What do those guys do every Saturday? They talk about white owls" is a bit weird, because it doesn't seem to be an activity that would usually happen with regularity due to its specificity. I can more readily imagine "They are talking about white owls" to be said.in relation to an ongoing individual moment ("What are they talking about?" "Do they mean all owls?" "Which white birds did they say?" etc.).
I suppose it depends in English whether we are referring to a particular time, or generally, as in "English people talk about the weather". (that is, they do it as a habit)