Plumages, Molts, and Structure

Adult

Sexes are identical in pattern, but variable in coloration and intensity, although without distinct color morphs. Also, this is the most size-dimorphic of falcons: female Orange-breasted Falcons may be twice the size and weight of a male and appear one-third or more larger. Feet, cere, and orbital eyering of adults are generally bright yellow , but may vary to a pale yellow or even a dull bluish green, similar to the immature.

From above, adults have a large, dark black head ("helmet"), a bluish black back with lighter blue gray feather edgings that may glisten in the sunlight or appear dark black in low light, and a slightly rounded tail that appears uniformly dark. Closer inspection reveals six light buff to bluish horizontal tail bars that may be hidden from view by the less distinct barring on the deck feathers. Barring is highly visible when the tail is fanned, such as while sunbathing, warbling (stretching), or drying wet plumage.

From the front, adults have a distinct white throat and bib, which wraps around the front of the neck, merging into a rufous orange crescent, which extends from the orange crop up through the cheek toward the back of the bird’s head. Individual birds are highly variable in the amount of white versus buffy rufous orange in the throat and bib area, but all show a degree of bright white beneath the lower mandible.

From the front, beneath the white throat and bib, the breast area is divided into three distinct areas of color gradation. The entire upper breast or crop area is a clear buffy, rufous orange (most Bat Falcons Falco rufigularis have a thin orange line beneath the white throat or no line at all, although some South American birds may appear to have a buffy rufous throat and bib). The midsection of the breast or vest is black, overlain with reddish brown horizontal coarse barring, becoming lighter and more distinct on the flanks (in darker individuals, the vest barring may be all rufous, giving the entire vest a solid dark appearance). The lower panel (belly) and thigh areas, as well as the undertail coverts, are a rich buffy orange, like the crop. The lateral edges of the undertail coverts may be clear to barred with black-and-white (or rufous) chevrons (like the immature Bat Falcon).

Wing-tips when crossed in a normal resting posture fall above the tip of the tail, by as much as half an inch for the male and a full inch for the female. When dozing, after a shower, or when sunbathing or preparing to fly, the wings may extend to or well below the tip of the tail.

Immature

The immature is paler (less vividly marked) overall than adults, with blackish head and dark brownish black back and tail, contrasting with a pale buffy breast overlain with horizontal dark brown barring on the flanks with brown chevrons on the thighs, panel (belly), and undertail coverts.

The crop is a much paler buff marked with brown teardrops dissolving into a clear buffy rufous bib and throat which extends into the crescents on the cheek and upper neck. The cere and orbital areas may be a dull pale bluish green, with greenish to pale yellow feet, changing more to the yellow spectrum with age. The tail has similar light barring of the adult, but much less vivid even during fanning (except for the diagnostic crescent, very similar to immature peregrine).

Little information, especially of Orange-breasted Falcon in the wild. Adults in a captive breeding population in North America initiate a complete molt in April or May, which continues through September or sometimes even later.

Feet, cere, and orbital eyering of adults are generally bright yellow, but may vary to a pale yellow or even a dull bluish green, similar to the immature.

In the immature, the cere and orbital areas may be a dull pale bluish green, with greenish to pale yellow feet, changing more to the yellow spectrum with age.

A medium-sized falcon, slightly larger to considerably larger than Bat Falcon (Falco rufigularis). Smaller than Arctic Peregrine Falcon (Falco peregrinus tundrius), but closer in size to South American Peregrine Falcon (Falco peregrinus cassini).

Length

Female: 38–40 cm (15–15.7")

Male: 35–36 cm (13.8–14.2")

Mass

Female: 550-700 g

Male:     325-425 g