Common Nighthawk, male. Males have white throats and white bar on tail, females have buffy throat and no bar. Both have white bar across wing tips.
Last night we counted 516 Common Nighthawks migrating over our property in southern NH. The weather was cool and overcast, not what you'd think was an ideal condition for migrating. We heard their telltale call, a nasal "peent", at around 4:00 PM, dropped everything and went down by our pond (which is a dammed up part of a river) to count them. Many of them were feeding over the water with their beautiful, acrobatic flight, seeming like very large swallows. They continued to come in along the ridge of the mountain across from us and at one point, we saw some drop down out of the clouds and join 131 others that were rising in a thermal, just like Broad-winged Hawks, very cool! We continued to watch and count until about 5:45 when they stopped appearing and the fog descended over the mountain.
What a thrill for us! Common Nighthawks are strange birds that feed at dusk and scoop up flying insects in their large mouths. They nest across much of the country, on gravelly soil in fields, or even gravel rooftops in cities. One of the best times to see them is during migration, which is taking place right now. So take your binoculars, go out at dusk to a location with good sight lines and see if you can spot them. We'll be looking too. If you live in certain parts of MA and NH, you can contribute to their Common Nighthawk migration study.
I photographed these birds, and even the Monarch Butterfly in flight, in challenging, cloudy conditions with my Canon 1D Mark II camera with a Canon IS 300 mm lens and a 1.4 teleconverter. Wish it had been sunny.