We had our outside around the house sprayed for bugs - now the birds

You could put out bird seed to bring them back. The birds might have been eating the bugs.

Plant sunflowers in pots.

Depending how far the bird houses are from the house, any chance some insecticide over spray got on the bird houses? I would clean them out of debri and wash them down with a hose. The odor of the insecticide may also be detering them.

Yes clean out the bird houses. For bird safety, I wouldn't try to bring them back until the pesticides have loss effectiveness. I once treated our lawn for ticks and for at least a month we had birds flying into our house. The birds were eating other dead bugs from our lawn. I still feel guilt.