Field Notes
The nightjar family, Caprimulgidae, is one of the most fascinating and least understood groups of birds. Around the world there are dozens of species, all sharing a similar blueprint: soft, cryptically patterned plumage, wide gaping mouths fringed with bristles, large eyes, and a nocturnal or crepuscular lifestyle. They are found on every continent except Antarctica, and yet most people have never seen one.
The European nightjar, which breeds across much of Europe and Asia and winters in Africa, is the species many readers of this blog will know best. Its churring song is the sound of a summer heathland, and its silent, moth-like flight as it hawks for insects against the last of the light is unforgettable once seen. Closely related is the jungle nightjar of South Asia, and the savanna nightjar, whose piercing calls ring out over open country from India to Indonesia.
In North America, the family is represented by species with wonderfully evocative names. The whip-poor-will, whose song is famously said to be named after its own call, breeds in eastern woodlands and is heard far more often than it is seen. Further west, the common poorwill occupies dry, rocky country, and the lesser nighthawk patrols the warm evening skies of the southwest. The nighthawks, including the widespread common nighthawk, are the most aerial members of the family, often hunting high overhead at dusk with stiff, bat-like wingbeats.
One of the most remarkable facts about this group concerns torpor. Several species, including the common poorwill, can enter a state of reduced body temperature and metabolism during cold spells when insect prey is scarce. This allows them to ride out periods of bad weather that would otherwise be fatal. It is a reminder of how finely tuned these birds are to the rhythms of their environment.
Not all nightjars are small and understated. The great eared-nightjar of Southeast Asia is a large, powerful bird with prominent ear tufts and a call that has been described as a ghostly, drawn-out whistle. The owlet-nightjars of Australasia, though not true nightjars, occupy a similar niche and add another layer to the family's story. And the oilbird of South America, a nocturnal fruit-eater that nests in caves and navigates by echolocation, is sometimes grouped nearby in older classifications, a reminder of how varied the nocturnal bird world can be.
What unites all these birds is their dependence on darkness and their vulnerability to changes in habitat. Heathland, scrub, open woodland, and savanna are all under pressure from development, agriculture, and altered fire regimes. Nightjars are also sensitive to disturbance at their daytime roosts and nest sites, which are often little more than a scrape on the ground.
Getting to know the family, even from a distance, changes how you listen at dusk. That dry purr on a summer evening is not just a pleasant sound; it is one branch of a worldwide nocturnal chorus, sung by birds that have been doing this for millions of years. Learning a few of their names is a good first step toward caring about whether they survive.
