Lots of Tree Swallows! (Note; September 11th: In the nine days since I posted these photos, there have been no more swallows on the marsh. Apparently, this day's behavior was their "revving up" for the beginning of migration south. These short flights remind me of the way Canada Geese begin to call and recruit others to call until in their frenzy, all take off. In the case of geese, often the call recruiting fizzles out several times before the threshold of excitement for flight is reached. Perhaps in swallows, the recruitment takes the form of these short "musical chairs" flights - until some threshold of excitement is crossed and flight is sustained and directed south.)