Having wintered in South America, common nighthawks do not return to the American Heartland until early May. Unlike some insectivores, such as tree swallows, they do not tempt fate by arriving before the threat of frost has passed. Their appearance is thus a welcome sign for winter-weary humans, a reassurance that gardens can be planted and that the balmy days of spring are fully entrenched.
After nesting on the ground in open woodlands or on the flat rooftops of urban buildings, they spend the summer cruising the evening and early morning skies, feasting on a wealth of flying insects. Stirred by the waning daylight and cool nights of late August and September, they begin to circle southward, often riding a northerly wind. Such flocks increase in size throughout September and, by early October, they disappear from the evening sky, safely ahead of the autumn chill.
The sight of migrating nighthawks is thus welcome during both legs of their annual journey. In May, we celebrate their return as a sign that winter has finally lost its grip and, in September, their flocks signal that the heat of summer is fading into the coolness of autumn. We humans are a fickle bunch!
