MrsD, are your yellow birds Goldfinches or some other finch variety? I have Goldfinches and a few Purple Finches.

Have you ever watched the hummingbird migration map at hummingbirds.net? Fascinating! I got to put up a dot one time, when I lived in Mississippi.

I love watching birds build nests! Last year an Eastern Phoebe built a nest over the light fixture on the front porch. They stack nests for each egg laying, and at the end of the season there were 3 distinct layers. Each nest had babies!