Northern Rough-winged Swallows

The other day I stopped by Castellow Hammock Park in southern Miami-Dade County, FL.  I was greeted by several Northern Rough-winged Swallows zooming in circular paths through the sky directly above me.   I tried to follow them and soon discovered that they were nesting in the birdhouses near the front entrance.  These little birds were a lot of fun to watch and a first for my Life List.  I watched them for several minutes as they went about their business.  They popped in and out of the birdhouse windows, chirping to each other constantly, and after awhile I think I was able to figure out what they were chirping about…

Northern Rough-winged Swallow (Stelgidopteryx serripennis)

Oooh La La! 

What?