Found in the tropical forests of the Americas all the way from Mexico to Argentina, the bat falcon (Falco rufigularis) is named for its ability to hunt bats. In fact, the bat falcon is a successful hunter of birds and insects, as well as bats. One of the best places to spot bat falcons is along riverbanks, including the Tambopata River, where they will perch conspicuously as they wait for bird species and insects such as large dragonflies to cross the open air space above the waterway. They may be seen singly, or occasionally in pairs.
With its distinctive markings, the bat falcon is certainly not difficult to spot; its upper parts are dark gray or black, while its throat is white, above a black-and-white striped breast and orange lower belly and thighs. Its long tail is mostly black. However, they do resemble the much less common orange-breasted falcon (Falco deiroleucus), and are only really distinguishable by their smaller size and more restricted orange plumage on the breast.
At around 30 centimeters in length, female bat falcons are much larger than males, which tend to measure around 23 centimeters in length. The male’s wingspan may reach up to 58 centimeters, while the female’s wingspan can be up to 67 centimeters. The bat falcon nests in the cavities it finds in cliffs, where it will lay two to four brown eggs, which the female will care for while the male assumes additional hunting duties.
The smaller male tends to hunt more insects, while the larger female will take more birds and bats. When observed in pursuit of their prey above the surface of rivers, they are notable for their rapid and direct flight. Powered by their specially adapted long pointed wings, bat falcons are among the planet’s fastest birds. The high-pitched call made by both males and females has been likened by observers to that of the northern hemisphere’s American kestrel.
The bat falcon’s habit of waiting for small birds to venture across waterways means that many species of small rainforest birds tend not to take such a risk, resulting in localized flocks of the same species living on different sides of a river, in total isolation from one another. Meanwhile, for their part the rainforest’s faster flying bird species, such as swifts, have no hesitation in flying across rivers, but they will do so in flocks, as a protective measure against the lurking bat falcon. Hummingbirds and swallows also number among the bat falcon’s favorite prey.
Bat falcons are known to fly several kilometers from their habitual territory in search of certain prey. Bats, the prey for which the bat falcon is named, tend to be most active at dusk and dawn, and in response to this behavior pattern the bat falcon differs from other diurnal falcon species by hunting in the half-light at the beginning and end of the day, in the hope of catching bats as they emerge from their roosts.