A cold grey day ... why are they here?

It has been very cold and gray why are these Robins still here?
or these American Goldfinches
Or these Cedar Waxwings.

I saw the Robins in the trees close by and took some pictures of them a little further away in the gray distance. When I got home and actually looked at what I shot I realized that I was looking at more than just the same Robins. The Waxwings are about the size and I knew the Goldfinches were smaller but I thought they were just some Black Cap Chickadees which are very common around here. Yet another case of not everything is what you think it is.