Mantled Hawk

Leucopternis polionota

Identification

Mantled Hawk Leucopternis polionotus is a largish buteonine considered Near Threatened. Perched adult appears chunky, with broad ‘shoulders’ relative to total length. White head looks large, round and conspicuous; markings around eyes afford a masked appearance. Cere and lores ash-grey to dull yellow; bill has paler grey base grading to black at tip. Irides brown in good light, otherwise appear black. Underparts unmarked white. Mantle, scapulars and tertials slaty grey with broad white tips affording a somewhat scaled pattern. Slate-black upperwing-coverts appear darker than scapulars. Secondaries dark lead grey with 3–4 narrow darker bands (in good views) and broad white tips form a shallow U if seen from behind. Secondaries reach halfway to tail tip, concealing rump and base of tail. Primaries black with greyer bases and thin white tips reach or slightly exceed tail tip, sometimes forming a small dark triangle below tail. Usually only the white part of the tail is visible, but in some individuals one, rarely two, dark bands are just visible at the tail base. Tail tip square. Tarsi yellow and usually partially concealed; toes strong and orangish yellow.

The Juvenile is very much like adult but dark streaks on crown and nape visible at distance. Upperwing-coverts fringed whitish. Cere whitish to dull yellow. Somewhat marbled dark bars at base of tail more numerous and noticeable than in adults. Flying birds have a unique silhouette with long, very broad, rounded wings and short tail. White head appears bulky and sometimes (in females?) projects further than tail. Wings longer than body and tail-length in soaring birds (wingspan 2.6˘ total length). Broad white trailing edge to wings conspicuous in good light (especially if backlit, but not obvious in cloudy conditions). All-white tail appears squarish if folded, slightly wedged when partially fanned, and rounded when fully fanned. Dark base of tail seldom noticeable. Seen from behind or if tail fully fanned, wings and tail form continuous trailing edge. Dark distal half of remiges contrasts with rest of underside, but border ill-defined, especially on secondaries. Leading edge to wings noticeably white. Legs not very apparent.

Distribution

It has been recorded from Alagoas to Rio Grande do Sul in eastern and southern Brazil20, north-east Argentina, east Paraguay and, perhaps, northern Uruguay.

Habitat

It inhabits humid forests, second growth and Paraná Pine Araucaria angustifolia mixed woodland, from sea level to at least 1,500 m.

Behaviour

Perches on exposed branches or bare snags in upper half of living trees, but also on dead ones. In hilly areas, it is usually found on the upper half of forested slopes. Perches quite straight with tarsi barely visible. Tail often held vertical or slightly forwards. Soars in circles, usually on level wings—but might hold wings above the horizontal in full soar— frequently and for long periods, low over forest or, mostly, high from mid morning until late afternoon. Once height attained, usually glides long distances on somewhat ‘cupped’ wings. Long broad wings give species a very conspicuous flight as birds seem to float in midair. Flapping shallow and ‘flexible.’ Birds flap very infrequently when soaring.

External Links

• Six page illustrated field identification of Mantled Hawk