There are two different topics being discussed here.
Topic 1) Bird populations overall. Lower, higher, or about the same?
Topic 2) To what extent the birds have started coming to feeders here in early winter. In the early part of the winter if the weather remains mild, you see less birds at feeders. And as the weather starts getting really wintery you see more birds coming to feeders. That is probably because the cold weather pushes more birds down from the north. And because the cold weather means they need more food, and access to natural foods decreases.