While I was at the American Museum [of Natural History] I was interested not only in bird taxonomy, but also in other aspects of birds. For instance, I discovered that there was a geographic variation of degree of sexual dimorphism in several species of these island birds, so that on one island both male and female looked… had the highly-colored plumage of a male. And another island the male was highly-colored, the female had a drab protective coloration and a third island, the same species… both male and female had the drab color of the female. So obviously… I don’t want to get technical now, this could not not be due to the sex hormones as was at that time believed by everybody, it had to have another meaning. So I got in touch with people working on the… the genetic determination of colour in chickens at Storrs, Connecticut, and they in turn got me in connection… in contact with Professor LC Dunn at Columbia University, a geneticist who was interested in such questions. And Dunn invited me to come to seminars, to Columbia University, which I did, and as I was going… and I… and I became more and more friendly with the department there. And then Professor Dobzhansky arrived from California, from Pasadena… who worked in TH Morgan’s laboratory to give the Jesup Lectures in 1936. And I invited him to come to the Museum and study my wonderful cases of geographic speciation of birds and he was quite excited about this, and I was excited about his lectures, and we became very good friends.