Why do Barn Swallow Birds Dive Bomb when there are loud noises present?

Question

(Like mowing the lawn) How do I find their nest?

Answer 1

They'll dive bomb anything they think is too close to their nest; it may be hard to find, barn swallows build mud nests that stick out from a vertical surface, such as the wall of a barn or a vertical roof beam. Just make sure it's legal in your area for you to remove the nest (and there aren't any babies in it), as barn swallows are protected in some regions. If it is all right to remove the nest, you'll have to check the area regularly, or they'll try to build another in the same place.

Answer 2

They are very protective of their nests, their mates and their babies. Watch them closely (& quietly) and  you will see them come and go from the same spot... which is where the nest is located. Don't go near it! You'll get an earful! kjl

Answer 3

You are obviously close to their nest or fledglings.  You should make sure the babies are not hiding in the grass before you mow...this might be why they are so upset.    They usually build mud nests on man-made structures.  It IS illegeal across the US to disturb, or destroy a nest of ANY wild native bird, they are protected by the Migratory Bird Treaty Act.  Just wanted to clear that up since someone else said they MIGHT be protected.