I had a number of ideas on bird migration and when I did, at that time, I was still a Lamarckian, let's remember that. And when I read this paper now I am just a little bit, shall we say, embarrassed. However, I had a number of ideas. At that time there was a good fight going on: why do birds migrate? And is the winter quarter the original home of the species from which they have expanded northward into their breeding territory? And so forth. And… I analyzed all these factors and wrote this paper, but when it wasn't quite finished yet I went to New Guinea and my good friend Wilhelm Meise, two years older than I, also a… a PhD candidate with [Erwin] Stresemann, finished it up and I might happily say that Meise is now just above 95 and he is still alive and still apparently in good shape. Well, the one thing in particular that I pointed out in this paper and which people didn't pick up until just about 20 years ago, is that there must be some competition between these hoards of northern migrants that settle in tropical areas or subtropical areas, and the resident bird population. And I suggested that this competition be studied by somebody. Well that is now being studied, but I'm quite sure, at least so far as I know the literature, I was the first person to point that out.