Michael Smith noted the only recorded nesting of BLSW in Oregon at Salt
Creek Falls in Lane Co.

As a teen-ager, I pointed out swifts to my father and grandfather at
McDowell Creek Falls (now a Linn County park) above Lebanon, OR. Grandpa
told me "yes, they nest behind waterfalls, like the Water Ousels". I am
ashamed to admit that I never returned there to search for nests or nesting.