Birds are back.

During the summer I took down the birdfeeders because the deer were making them a regular stop. As a consequence I didn't see any chickadees or titmice all summer. The woodpeckers flew through occasionally as did some goldfinch. When I put back up the feeders I wondered how long before the birds found them again. They must have been keeping watch because they were back the very next day. So how do they know? Do they communicate that with each other and between species?

This is the nest of the wren who built it in my hanging plant. It's like a little cave.