One of the earliest and most beautiful of the fall migration spectacles is that of the Common Nighthawk. The Nighthawk is an uncommon nester in New Hampshire, but come the end of August, hundreds will pass through in loose flocks, best observed at evening, floating on long, narrow, pointed wings. Their buoyant, erratic flight reminds many of an overgrown butterfly. We'll join Rob Woodward next Tuesday evening as he and other volunteers collect data on this beautiful bird. Our observation platform is the top level of the Capital Commons Parking Garage, 75 Storrs St., Concord. We'll meet just before 6:00 p.m. and stay until 7:30.