Mozart is from the same shop Olive came from, I got him last December. They had about 10 supposed male canaries in individual cages on the wall. But the problem was, I bought an identical canary the year before there as a male, and it laid an egg a week later! I returned her for a refund that year but by then they had sold out of males. I only brought home Mozart after waiting for a while in the shop, he was the only one which I actually saw sing - and he just kept going and going!
I do love the yellow canaries but the green ones seem to have a stronger voice.