We had a pair of nesting robbins hatch 4 eggs in a rafter
above our patio. The little birds took off and lived in our garden for a
while. They are gone now.........Now the birds are back building a new
nest (the other is now vacant). Why aren't they using the same
next? And why so late in the year? Or is this a different pair?
Many smaller birds will raise two broods in one season when conditions are
favorable. One reason they build a second nest instead of reusing the first
may be because nests become very dirty and host many parasites. Its likely
the second nest is being built by the same pair as the first but it could be
a different pair.