Featured raptors: Black Hawks of Panama

The Accipitridae is a family of diurnal small to large birds of prey with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-sized mammals, with a number feeding on carrion and a few feeding on fruit. The Accipitridae have a cosmopolitan distribution, being found on all the world's continents (except Antarctica) and a number of oceanic island groups. Some species are migratory. This family includes eagles, hawks, harriers, kites, and even Old World vultures.

Hawk is a common name for some small to medium-sized birds in this family.

Buteogallus genus

Buteogallus is a genus in the family Accipitridae. All members of this genus are essentially Neotropical. Many of the species are fond of large crustaceans and even patrol long stretches of shore or riverbank on foot where such prey abounds, but some have a rather different lifestyle.

Four members of the genus occur in Panama but we will focus on the two black hawks:

Common Black Hawk (Buteogallus anthracinus) breeds in the warmer parts of the Americas, from the Southwestern United States through Central America to Venezuela, Peru, Trinidad, and the Lesser Antilles. It is a mainly coastal, resident bird of mangrove swamps, estuaries and adjacent dry open woodland, though there are inland populations, including a migratory population in north-western Mexico and Arizona. It feeds mainly on crabs, which gives his Spanish common name "Gavilán Cangrejero" (Crab-eating hawk), but will also take small vertebrates and eggs. Its call, a distinctive piping whee-whee-whee-whee-whee.

The adult common black hawk is 43–53 cm (17–21 in) long, has very broad wings, and is mainly black or dark gray. The short tail is black with a single broad white band and a white tip. The bill is black and the legs, cere and lore are yellow. The adults resemble zone-tailed hawks, but have fewer white bars on their tail and are larger in size.

In Panama it's common on both coasts, on islands, and sometimes inland along larger rivers and lakes.

 Common black hawks have black bill and yellow cere

 Common black hawk in El Salado beach, Aguadulce

Common black hawk in Coiba Island, where it is very common.

Great Black Hawk (Buteogallus urubitinga) is a resident from Mexico through Central America to Peru, Trinidad and northern Argentina. It resembles the Common Black Hawk, but is larger with a different call. It's also a mainly coastal bird but also found in forest and open woodland near water.

The adult great black hawk is 56 to 64 centimeters long. It has very broad wings, and is mainly black. The short tail is white with a broad black tip. The bill is black and the legs and cere are yellow. Western Panama race has slaty lores, while Eastern race shares yellow lores with common black hawks but usually shows white bars on thighs. Immature birds are dark brown above with spotting and streaks. Their underparts are buff with dark spots, and the tail has a number of black and dusky bars. The call of great black hawk is a distinctive whistling scream ooo-wheeeeee.

The great black hawk feeds mainly on reptiles, other small vertebrates and large insects, often hunted on foot. This species is often seen soaring above woodlands.

In Panamá it's uncommon on both slopes in upper levels of forest, usually near water but less so than common black hawk.

 Note the darkish loves, different tail pattern and bulkier body

 Immature great black hawk

Some individuals can be identified by the white lines on their thighs

Buteo genus

Buteo is a genus of medium to fairly large, wide-ranging raptors with a robust body and broad wings. In the Old World, members of this genus are called "buzzards", but "hawk" is used in America

Two hawks of the genus Buteo, with black coloration, occur in Panama:

Zone-tailed Hawk (Buteo albonotatus) is a medium-sized hawk of warm, dry parts of the Americas. It is somewhat similar in plumage and flight style to the turkey vulture, and may benefit from being able to blend into groups of vultures. It feeds on various small mammals and birds.

Zone-tailed hawks range from parts of southern USA to northern Argentina. In winter they generally withdraw from the U.S.A. and northernmost Mexico, with these populations wintering mostly in Oaxaca and the Yucatán Peninsula. The hawks of Central America may be seasonally migratory, although their movements are not well known. Zone-tails sometimes wander out of their normal range. 

It's fairly large at 46 to 56 cm (18 to 22 in) but slender. The adult plumage is mostly blackish. The notable exception is that the flight feathers are barred with lighter gray, which can appear solid silver-gray from a distance. The tail has three or four bands (the "zones" of the common name). The cere and legs are yellow, the lores are light gray and a light touch of white may be seen on the face. Immatures are similar except for small white spots on the breast and tails with narrow gray and black bands and a broad dark tip. 

In Panama it's uncommon on Pacific slope, with records on Caribbean slope from Canal Area and eastern Kuna Yala.

Zone-tailed hawk soaring close to Matías Hernández river, Panamá city

Note flight feathers barring and distinguishable tail banding

Note white on face. Also note white spots and tail banding on immature.

Short-tailed hawk (Buteo brachyurus) breeds in the tropical and subtropical Americas from southeastern Brazil and northern Argentina north through Central America to northern Mexico, as well as in southern Florida. It has a less common dark morph that is most similar to zone-tailed hawk, but is stockier, with shorter wings and tail, and less prominent tail banding. Also shows a whitish patch on primaries. In Panama it's uncommon on both slopes, usually found in open areas, occasionally over forest.