Zen is right.

Please check with your DFG (Dept of Fish and Game) Disturbing of protected species can get really expensive.

Shoot a swan and you are looking at >$5000 fine and confiscation of your gun.

Disturbing an egret nest will cost you in excess of $10,000 fine from the federal government plus jail time.

Growing up, we lived in Kansas for about two years, just outside my sister's room, a woodpecker decided to peck and peck. That bugger came everyday. My sister was losing sleep, my father was getting mad that the house was getting pecked apart. He called DFG to find out what he could do. They gave him a form to fill for re-imbursment for the repair cost. And a warning of NOT disturbing the bird. All woodpeckers in US are protected.

Swallows may be protected so do check.

Meanwhile, can you place a plastic tarp below the nest and weigh the corners. And place newspaper on top of the plastic. Replace the newspaper each day. Yes its bit of a hassle. or continue to hose down every day.

my sympathy,
Smilingcat