Black Falcon Falco subniger Scientific name definitions

The Black Falcon occurs over much of continental Australia, where it is endemic. It is rare and sporadic in the southwestern quarter of mainland Australia, but otherwise occurs and breeds over much of the flatter, lowland parts of the continent. It occurs on the eastern tablelands at higher elevations, above 800 m, mostly as a post-breeding visitor from late spring to autumn. Breeding pairs in the temperate to subtropical southeastern and eastern lowlands appear to be resident, but pairs breeding in the tropical north withdraw from the coastal plain during the summer wet season. It can be common in the eastern arid zone in wet years, and, in the inland parts of its range, it is attracted to plagues of rodents or locusts, or to population increases of quail (Coturnix) or buttonquail (Turnix). Black Falcon inhabits most open and lightly wooded habitats and climatic zones and occupies stick nests in mature woodland trees. It avoids the most rugged and densely or continuously forested areas, where the similarly sized but more aggressive and dominant Peregrine Falcon (Falco peregrinus) occurs. It seems to be generally most abundant in the agricultural belt of inland eastern Australia where significant remnant woodland, especially riparian, remains.

The Black Falcon is a moderately large falcon (male ~590 g, female ~830 g). Although appearing almost black at a distance, it is not truly black, with juveniles being a dark sooty-brown and adults a mid to dark chocolate-brown, with the lightest individuals also having variable pale highlights to the plumage such as a pale face and throat, speckled upper breast, and fine barring under the wings and tail. It is generally inconspicuous and mostly silent away from the nest, variously soaring high, flying low, or perching quietly in a living or dead tree, although it is sometimes attracted to farm activities such as agricultural machinery, herding of livestock, or burning of crop stubble, or shooters, searching for any prey that may be flushed or injured. Its main interactions with humans relate to accidental mortality and injury from collisions with vehicles, wire fences, power lines, or, occasionally, windfarm turbines.

The Black Falcon is a fast and agile predator of a wide array of mammals, birds, reptiles, and insects in varying proportions according to locality and climatic zone. Prey size ranges up to immature rabbits, birds up to duck and crow size, and reptiles including skinks and small monitor lizards. Agile prey is taken in a fast dive or chase in the air, around the tree canopy, or to the ground. Carrion is sometimes taken, typically fresh road-killed mammals or birds, and prey is commonly robbed from other raptors. Insects are also commonly taken, typically large volant species such as grasshoppers or locusts.

The age at which the Black Falcon establishes a territory is unknown, partly because juveniles acquire adult-like plumage with the first post-juvenile molt towards the end of their first year, but also because there has been little or no banding or color-banding of individuals. Home-range size is unknown, but breeding adults ranging up to at least 6 km from the nest suggest that it may be about 100 km² in the southeastern agricultural belt. Breeding pairs occupy, but do not repair, an available stick nest annually at the start of the breeding season and may reuse a nest in successive years as long as it remains serviceable.

Black Falcons in the temperate and arid zone select, occupy, and guard available stick nests in autumn (April), and the breeding cycle from egg-laying in winter (July) to fledging in spring occupies ca. 3 months, with the post-fledging dependence period extending the whole cycle to five months. Early mishaps and repeat laying can extend laying to late spring. Successful pairs raise between one and four young per year, with some rearing many more in their lifetimes if they are successful for several years in a row. Breeding productivity appears to depend on food availability and weather.

Confusion between dark-colored individuals of the Brown Falcon (Falco berigora) and the Black Falcon has affected the reliability of historical (pre-1980) literature on the Black Falcon, with the most reliable information having come from field studies conducted or published since 1980. Most studies of Black Falcon have been conducted in temperate to subtropical southeastern and eastern Australia, with few in the arid zone and tropics. Gaps in knowledge include dispersal or migration routes and destinations of juveniles, age at first breeding, population-level impact of agricultural chemicals (e.g., insecticides and rodenticides), biology of pre-breeding and nonbreeding individuals, and ecological information in regions where the species is little studied (e.g., the tropics).