Nighthawks on the Move

Sitting outside in our yard, reading and looking up into the sky.  How so unlike this it was in May and June, being persecuted by the buffalo gnats!  Now I can sit and stare, and nothing bothers me.  I looked up when I heard a bank swallow calling far overhead, and then four nighthawks glided over my home.  Staging in the skies, preparing for the fall migration, or probably in the midst of it.  What if they were from the north country, where I have just returned from?  Door County, Wisconsin, nighthawks?