Family FALCONIDAE Leach, 1820

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Introduction

The Falconidae are cosmopolitan, the group composed of small to medium-sized diurnal raptors; there are 67 species within 11 genera, of which six Falco species occur in Australia. One Australian species F. peregrinus occurs from Greenland to Fiji although represented by several subspecies. All are usually solitary and territorial although feeding congregations may occur if food is in abundance. The family has been divided into two subfamilies: Polyborinae (caracaras, laughing falcon and forest falcons); and Falconinae (falcons, kestrels and falconets).

The divisions within the family are based on physical characters and habits. All of the fastest fliers have enlarged pectoral muscles, these are the large true falcons with stocky and powerful bodies, pointed wings and short tails. The medium-sized hobbies and kestrels are smaller and have wings that are narrow but long. All have evolved remarkable eyesight and flying abilities. Their plumage is composed of a mix of brown, white, chestnut, black and grey shades, often with barring. There is little difference in the plumage of males and females, although some, such as F. cenchroides, exhibit sexual dimorphism in plumage and body size; the female has the larger body.

Other characteristics of the family include a strongly hooked bill with a fleshy cere covering the nostrils, the maxilla having a notch or tooth and a distinctive dark area or tear-mark passing through eye. The anisodactyl feet are affixed with sharply curved talons that lack the spasmodic clutching mechanism of the Accipitridae. Vocalisations are few and generally uttered during breeding — as the pair performs a change in incubation or nest attendance. These calls are mostly short screams or chattering, in the case of F. berigora the birds utter a short series of cackling notes during displays.

The family may be found in a variety of habitats, but principally in open or fairly open areas. In Australia they are found in all areas including urban areas although they are more frequently found in open country. Elsewhere their preference varies from tundra to desert and rainforest from sea level to alpine regions.

Several methods of prey capture are utilised: larger species pursue prey by rapid flight and stooping while smaller species prefer to hover and drop method. The former method immobilises the prey by a strike, employing their specialised talons; the prey is then carried to either a perch or the ground where it can be despatched by severing the neck with a bite. The latter method, used by kestrels is accomplished with fanning wings and tail and is often adopted by larger F. berigora. Prey include birds, insects, bats and other small mammals.

Breeding pairs may mate either temporarily or permanently. The mating displays are aerial performances conducted in the vicinity of the nest site and incorporating aerial chases and courtship feeding. Two Afro-European hobbies (F. eleonorae and F. concolor) breed in loose colonies while the remainder nest solitarily. Nests are often reused for several years, with an annual refurbishment. The initial nest is usually not constructed by the falcon, but is simply the nest of another species. The stick platform selected as nest sites are principally those placed on ledges of rock faces or tall buildings (F. peregrinus) and tree cavities.

Clutches vary from 3–5 for the larger species and 3–6 for the kestrels and eggs are laid at intervals of 2–3 days. The eggs are cylindrical or short-ovals with a buff base colour, each is heavily dotted with dark red-brown and they are incubated for between 25–35 days. These newly hatched young are nidicolous and in their short period in the nest go through two downs. Normally the nestling period for the large species is 40–49 days while the kestrels take 25–32 days. During the nesting period the male hunts to feed the sitting female and young.

Excluded Taxa

Vagrant Species

CAVS:8094
FALCONIDAE: Falco peregrinus calidus Latham, 1790 [Siberian Peregrine Falcon] — Marchant, S. & Higgins, P.J. (eds) 1993. Handbook of Australian, New Zealand and Antarctic Birds. Melbourne : Oxford University Press Vol. 2. [319]

CAVS:8093
FALCONIDAE: Falco subbuteo Linnaeus, 1758 [Eurasian Hobby]

General References

Campbell, B. & Lack, E. (eds) 1985. A Dictionary of Birds. Calton : T. & A.D. Poyser xxx 670 pp.

Christidis, L. & Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. Melbourne : CSIRO Publishing 288 pp.

Wink, M. & Sauer-Gürth, H. 2004. Phylogenetic relationships in diurnal raptors based on nucleotide sequences of mitochondrial and nuclear gene markers. pp. 483-498 in Chancellor, R.D. & Meyburg, B.-U. Raptors Worldwide. Budapest : WWGBP/MME.

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