"Alle vogel sind schon tot" I think is a play on a line from a spring song I learned in German class in high school, "Alle Vogel sind schon da" (All the birds are already there). I hope the book turns out as funny in German as it is in English.
In other words, the German title is a pun! Okay, I can get that. I suspect Falscher Vogel fängt den Tod will turn out to be another pun.
And in answer to Liz Clifford--yes, I collect the foreign editions of my books. In fact, I have a shelf in one corner of my office where I keep all the editions I can get my paws on--hardback, paperback, large type, foreign, and audio. The photo at the top of the blog shows what it looks like at the moment--including the armed action figures I keep around to guard it.