Gray-lined Hawk Buteo nitidus Scientific name definitions

38–46 cm; male 350–497 g, female 320–592 g (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ); wingspan 75–94 cm (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ). Grey overall, with fine dark grey barring above  and bolder white barring below; tail black with 1–2 prominent white bands  . Eyes, cere and legs yellow. Female averages 4–9% larger and up to 29% heavier than male. Immature blackish-brown above, with white and buff mottling; below  buffy white, with brown streaks on breast, spots on belly; tail brown with darker bands and whitish tip. Race <em>blakei</em> is smallest, darker than nominate, finely barred above and below; nominate race intermediate in size, indistinctly barred above and narrowly barred below; race pallidus is largest, lightest below and exhibits the least sexual size dimorphism (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ).

Editor's Note: This article requires further editing work to merge existing content into the appropriate Subspecies sections. Please bear with us while this update takes place.

This species and B. plagiatus sometimes placed in Asturina, partly because of distinctive moult pattern. Probably closest to B. ridgwayi and B. lineatus; previously considered to form a clade with these and Rupornis magnirostris, but latter found to be basal to all buteos (2 Riesing, M. J., L. Kruckenhauser, A. Gamauf, and E. Haring (2003). Molecular phylogeny of the genus Buteo (Aves: Accipitridae) based on mitochondrial marker sequences. Molecular Phylogenetics and Evolution 27(2):328–342. Close , 3 Lerner, H. R. L., M. C. Klaver, and D. P. Mindell (2008). Molecular phylogenetics of the buteonine birds of prey (Accipitridae). Auk 125(2):304–315. Close , 4 Amaral, F.S.R., Sheldon, F.H., Gamauf, A., Haring, E., Riesing, M., Silveira, L.F. and Wajntal, A. (2009). Patterns and processes of diversification in a widespread and ecologically diverse avian group, the buteonine hawks (Aves, Accipitridae). Molecular Phylogenetics and Evolution. 53(3): 703–715. Close ), and this group may be more closely allied to Leucopternis than to Buteo. Until recently, commonly considered conspecific with B. plagiatus, which differs in its plain vs barred grey crown, nape, back and wings (3); uppertail coverts white vs grey with white tips, resulting in bold vs narrow white band on base of uppertail (2); and longer call, without sudden drop in pitch in middle of note (2, perhaps 3) (5 Millsap, B.A., Seipke, S.H. and Clark, W.S. (2011). The Gray Hawk (Buteo nitidus) is two species. Condor. 113(2): 326–339. Close ). N race blakei previously known as costaricensis, but latter name invalid, as preoccupied (by B. jamaicensis costaricensis). Three subspecies usually recognized.

Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Adaptable, found in lowland tropical to subtropical zones in rain forest edge, disturbed forest and open aridlands; like B. plagiatus, favours gallery and other riverine forest for nesting and avoids dense humid forest. Occurs mostly from sea-level to 800 m; reported to 1200 m in Panama and 1300 m elsewhere.

Generally considered sedentary.

Mostly lizards and small snakes  ; birds  , including small species of both understorey and canopy, and a parakeet (Aratinga); also rodents, large Orthoptera and beetles. Soars for short periods, but usually hunts from a perch ; agile hunter in forest, taking lizards from branches. More powerful and faster than Rupornis magnirostris.

There are two primary vocalizations: a series of 3–8 piping notes used primarily during the breeding season and a single-note alarm call given at intervals. Calls described as a series of mellow, piping overslurred whistles sounding like "wheeuw..wheeuw..wheeuw" and shorter piercing notes that quickly drop in pitch.

Nesting not as well studied for present species as for B. plagiatus. Reported to nest from Dec–Jul in Costa Rica; Jan–May in Colombia and Venezuela; Feb in Panama and Surinam; Apr on Trinidad (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ). Relatively small stick  nest  lined with sprigs, high in tree at forest edge. Aerial courtship, with stoops from great heights (up to 500 m) and mock chases. Usually two eggs (1–3); more than one young can be raised; incubation 32 days; chicks have white down, greyish above; fledging  c. 42 days. Aggressively drives other raptors from nest area.

Not globally threatened (Least Concern). CITES II. No hard data on numbers or population trends, but generally considered widespread, locally common to relatively numerous, and adaptable, using a wide variety of forested and semi-forested habitats that include disturbed and secondary forests. That said, deforestation in Amazonia and other parts of the range could be detrimental to the species.