come back every spring and clean out the nests and bring new feathers to line the nest. i still am not sure where they get the little mud balls to make the nests. there is not a place where there is water to wet the soil, like a cattle tank or water trough anyplace near. also, i wonder how they roll the mud into little balls. with their wings or beaks? it would be a big mouth full for them to carry one of those mud balls. they get the job done. they will stay through the summer and have maybe three sets of eggs. they hatch one set, usually 