Buteogallus
Encyclopedia
Buteogallus is a genus
of bird of prey
in the family
Accipitridae
. All members of this genus are essentially Neotropical, but the distribution of a single species extends slightly into extreme southern USA. Most are known as black-hawks (though not all species
are dark) or mangrove-hawks (though can also be found far inland). For the entire group the name crab-hawks seems most apt, in reference to the fact that all species are quite fond of large crustacean
s and will even patrol long stretches of shore or riverbank on foot where such prey abounds, but there are a number of birds with somewhat different lifestyle which appear so closely related that they ought to be included here.
Almost all species have a very characteristic tail pattern. This consists of a black base, a wide white middle band, a roughly equally wide black band, and a quite narrow white band on the feathertips that is often hard to discern or may be lost when the feathers are very worn. In the Great Black-hawk, the basal black is either missing or wider depending on subspecies
, but in the former case the body near the tail base is black, resulting in an almost identical appearance. Only the Rufous Crab-hawk
has a very different tail pattern (see also below).
, sorted according to putative relatedness:
However, delimited so strictly the genus is probably paraphyletic. The solitary eagles (Harpyhaliaetus
) are a more continental relative of the "black" group of Buteogallus – in phenotype
they are essentially hefty Common Black-hawks with lighter body plumage and in one species a small tuft. Insofar as there are differences in anatomy
, these seem to be related to the different prey they hunt (namely reptile
s). Together with the Savanna Hawk
, they seem to be close to some species uncomfortably placed in Leucopternis
. As that genus is apparently polyphyletic, it seems as if the best course of action would be to unite the crowned eagles with Buteogallus, as well as some "Leucopternis", to agree with the morphological
and mtDNA sequence
data.
These would include the Plumbeous Hawk
(L. plumbeus) and the Slate-coloured Hawk
(L. schistaceus), which since long were proposed time and again to be placed in Buteogallus. Together with the crab-hawks and solitary eagles form a sequence of plumage patterns that nicely agrees with the DNA-based phylogeny: L. schistaceus looks very much like a smaller, shorter-legged and lighter Common Black Hawk, while the basal L. plumbeus lacks the tail pattern. The case of the White-necked Hawk
(L. lacernulatus) is more puzzling. It is visually and ecologically almost identical to the sympatric Mantled Hawk
(L. polionotus) and some allopatric White Hawk
s (L. albicollis) but differs in tail color. According to the mtDNA data, it is very closely related to the Savanna Hawk, which is visually completely unlike, appearing like a very light Buteogallus which has an ochre-grey coloration due to abundant pheomelanins. Either there has been strong convergent evolution
in plumage and ecology - perhaps a case of mimicry - between the White-necked and the Mantled Hawks, or the mtDNA data is misleading due to ancient hybrid introgression. In the respect, it is interesting to note that the White-necked Hawk specimen sampled showed indications of heteroplasmy
.
The placement of the peculiarly apomorphic Rufous Crab-hawk
in regard to all these birds must be considered unresolved for the time being.
and never seems to have occurred outside the Americas
. From the time of the last ice age, an array of prehistoric species is known, some of them very large. On Cuba
, a particularly gigantic species survived deep into the last ice age, but probably not until human settlement.
In addition, if the solitary eagles merged into Buteogallus, the prehistoric Amplibuteo
would almost certainly have to be merged herein too, as it is hardly distinct from Harpyhaliaetus.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of bird of prey
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....
in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Accipitridae
Accipitridae
The Accipitridae, one of the two major families within the order Accipitriformes , are a family of small to large birds 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...
. All members of this genus are essentially Neotropical, but the distribution of a single species extends slightly into extreme southern USA. Most are known as black-hawks (though not all species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
are dark) or mangrove-hawks (though can also be found far inland). For the entire group the name crab-hawks seems most apt, in reference to the fact that all species are quite fond of large crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s and will even patrol long stretches of shore or riverbank on foot where such prey abounds, but there are a number of birds with somewhat different lifestyle which appear so closely related that they ought to be included here.
Almost all species have a very characteristic tail pattern. This consists of a black base, a wide white middle band, a roughly equally wide black band, and a quite narrow white band on the feathertips that is often hard to discern or may be lost when the feathers are very worn. In the Great Black-hawk, the basal black is either missing or wider depending on subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
, but in the former case the body near the tail base is black, resulting in an almost identical appearance. Only the Rufous Crab-hawk
Rufous Crab-hawk
The Rufous Crab Hawk or Rufous Crab-hawk, is a species of bird of prey in the Accipitridae family.It is found in Brazil, French Guiana, Guyana, Suriname, Trinidad and Tobago, and Venezuela....
has a very different tail pattern (see also below).
Systematics and taxonomy
This genus contains the following speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, sorted according to putative relatedness:
- Rufous Crab Hawk, Buteogallus aequinoctialis
- Common Black HawkCommon Black HawkThe Common Black Hawk is a bird of prey in the family Accipitridae, which also includes the eagles, hawks and Old World vultures. It formerly included the Cuban Black Hawk as a subspecies...
, Buteogallus anthracinus- Mangrove Black HawkMangrove Black HawkThe Mangrove Black Hawk, Buteogallus anthracinus subtilis, is a bird of prey in the family Accipitridae. Traditionally treated as a distinct species, recent evidence strongly suggests it should be considered a subspecies of the Common Black Hawk .The Mangrove Black Hawk is a resident breeding bird...
, Buteogallus (anthracinus) subtilis – formerly considered a distinct species, but now considered a subspecies.
- Mangrove Black Hawk
- Cuban Black Hawk, Buteogallus gundlachii – formerly included in B. anthracinus
- Great Black HawkGreat Black HawkThe Great Black Hawk, Buteogallus urubitinga, is a bird of prey in the family Accipitridae, which also includes the eagles, hawks and Old World vultures....
, Buteogallus urubitinga - Savanna HawkSavanna HawkThe Savanna Hawk is a large raptor found in open savanna and swamp edges. It was formerly placed in the genus Heterospizias. It breeds from Panama and Trinidad south to Bolivia, Uruguay and central Argentina....
, Buteogallus meridionalis
However, delimited so strictly the genus is probably paraphyletic. The solitary eagles (Harpyhaliaetus
Harpyhaliaetus
Harpyhaliaetus is a genus of eagles. Recent studies have shown that the Solitary Eagle is closely related to the black-hawks, in particular the Savanna Hawk which is smaller and browner but otherwise very similar to "Harpyhaliaetus"...
) are a more continental relative of the "black" group of Buteogallus – in phenotype
Phenotype
A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...
they are essentially hefty Common Black-hawks with lighter body plumage and in one species a small tuft. Insofar as there are differences in anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
, these seem to be related to the different prey they hunt (namely reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s). Together with the Savanna Hawk
Savanna Hawk
The Savanna Hawk is a large raptor found in open savanna and swamp edges. It was formerly placed in the genus Heterospizias. It breeds from Panama and Trinidad south to Bolivia, Uruguay and central Argentina....
, they seem to be close to some species uncomfortably placed in Leucopternis
Leucopternis
Leucopternis is a Neotropical genus of bird of prey in the Accipitridae family. They are generally associated with tropical or subtropical forests, and most are uncommon or rare...
. As that genus is apparently polyphyletic, it seems as if the best course of action would be to unite the crowned eagles with Buteogallus, as well as some "Leucopternis", to agree with the morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
and mtDNA sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
data.
These would include the Plumbeous Hawk
Plumbeous Hawk
The Plumbeous Hawk is a species of bird of prey in the Accipitridae family.It is found in Colombia, Ecuador, Panama, and Peru.Its natural habitat is subtropical or tropical moist lowland forests....
(L. plumbeus) and the Slate-coloured Hawk
Slate-coloured Hawk
The Slate-coloured Hawk or Slate-colored Hawk is a species of bird of prey in the Accipitridae family: the hawks, eagles, and allies....
(L. schistaceus), which since long were proposed time and again to be placed in Buteogallus. Together with the crab-hawks and solitary eagles form a sequence of plumage patterns that nicely agrees with the DNA-based phylogeny: L. schistaceus looks very much like a smaller, shorter-legged and lighter Common Black Hawk, while the basal L. plumbeus lacks the tail pattern. The case of the White-necked Hawk
White-necked Hawk
The White-necked Hawk is a species of bird of prey in the Accipitridae family.Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical moist montanes, and plantations. The species feeds on insects and other invertebrates...
(L. lacernulatus) is more puzzling. It is visually and ecologically almost identical to the sympatric Mantled Hawk
Mantled Hawk
The Mantled Hawk is a species of bird of prey in the Accipitridae family.It is found in Brazil, Paraguay, and Uruguay. Its natural habitat is subtropical or tropical moist lowland forests. It is becoming rare due to habitat loss.-References:* BirdLife International 2004. . Downloaded on 24...
(L. polionotus) and some allopatric White Hawk
White Hawk
The White Hawk , a bird of prey breeding in the tropical New World, belongs to the family Accipitridae of the Falconiformes; it is sometimes separated in the Accipitriformes with the other hawks and their relatives...
s (L. albicollis) but differs in tail color. According to the mtDNA data, it is very closely related to the Savanna Hawk, which is visually completely unlike, appearing like a very light Buteogallus which has an ochre-grey coloration due to abundant pheomelanins. Either there has been strong convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
in plumage and ecology - perhaps a case of mimicry - between the White-necked and the Mantled Hawks, or the mtDNA data is misleading due to ancient hybrid introgression. In the respect, it is interesting to note that the White-necked Hawk specimen sampled showed indications of heteroplasmy
Heteroplasmy
Heteroplasmy is the presence of a mixture of more than one type of an organellar genome within a cell or individual...
.
The placement of the peculiarly apomorphic Rufous Crab-hawk
Rufous Crab-hawk
The Rufous Crab Hawk or Rufous Crab-hawk, is a species of bird of prey in the Accipitridae family.It is found in Brazil, French Guiana, Guyana, Suriname, Trinidad and Tobago, and Venezuela....
in regard to all these birds must be considered unresolved for the time being.
Fossil record
The fossil record of Buteogallus has meanwhile turned out to be quite rich indeed, with many species being erroneously assigned to other genera at first. The genus – like many buteonines of today – probably succeeded earlier birds of prey during the MioceneMiocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
and never seems to have occurred outside the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
. From the time of the last ice age, an array of prehistoric species is known, some of them very large. On Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
, a particularly gigantic species survived deep into the last ice age, but probably not until human settlement.
- Buteogallus enectus (Middle Miocene; Sheep Creek, Sioux County, USA)
- Buteogallus sodalis (Middle Pleistocene; Fossil Lake, Oregon) – formerly in AquilaAquila (genus)Aquila is the genus of true eagles. It is often united with the buteos, sea eagles and other more heavyset Accipitridae, but more recently it appears as if they are less distinct from the more slender accipitrine hawks than believed...
- Buteogallus fragilis (Late Pleistocene; Southwestern USA) – formerly in ButeoButeoButeo 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 North America...
or Geranoaetus - Buteogallus milleri (Late Pleistocene of Southwestern, USA) – formerly in Buteo or Geranoaetus
- Buteogallus borrasiButeogallus borrasiButeogallus borrasi is an extinct species of giant buteonine hawk formerly endemic to Cuba. It probably fed on megafauna.It was so huge compared to other Buteogallus that it was long believed to be a titan-hawk or even an Aquila eagle. No proper common name exists due to this misconception...
(prehistoricLate Quaternary prehistoric birdsPrehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists...
) – formerly in Aquila or TitanohieraxTitanohieraxTitanohierax is an fossil genus of giant hawk from Cuba, Hispaniola and the Bahamas. It has one known species, Titanohierax gloveralleni. The extinct crab-hawk Buteogallus borrasi was formerly placed in this genus.... - Daggett's EagleDaggett's EagleThe Daggett's eagle is actually a rather long-legged species of hawk. It probably resembled the modern day savanna hawk with long legs. Many scientists think that these legs evolved because it caught snakes and reptiles, so it could keep its distance, similar to the secretary bird of Africa...
, Buteogallus daggetti (prehistoric)
In addition, if the solitary eagles merged into Buteogallus, the prehistoric Amplibuteo
Amplibuteo
Amplibuteo is an extinct genus of birds of prey, belonging the family Accipitridae....
would almost certainly have to be merged herein too, as it is hardly distinct from Harpyhaliaetus.