Tiny Hawk
Encyclopedia
The Tiny Hawk is a small diurnal bird of prey
found in or near forests, primarily humid, throughout much of the Neotropics. It is primarily a bird-eater, and is known to prey on hummingbird
s.
Usually named Accipiter superciliosus, it is the only species
of the genus
Accipiter
yet studied which has a large procoracoid foramen
. It also differs from the typical sparrowhawk
s in other respects of its anatomy
and in its DNA sequence
. Consequently, its old name Hieraspiza superciliosa may be more appropriate.
of Tiny Hawk, separated by the northern Andes
. The two differ most significantly in relative tail length; differences in size and color are small, and can be hard to distinguish.
The Tiny Hawk and its sister species, the upland-dwelling Semi-collared Hawk ("A." collaris), form a superspecies
.
es, or about the size of a Turdus thrush), though females are slightly larger at 26.5 cm (10.5 in). It is one of the smallest true raptors in the world and is one of the smallest Accipiter
species, though the Little Sparrowhawk
of Africa is of similar or even smaller size. The birds range in weight from 75–120 g
(0.17–0.26 lb
). As with most raptors
, there is considerable sexual dimorphism
in size, with females measuring 5–26 percent longer and as much as 60 percent heavier than males.
The adult male Tiny Hawk is dark slaty gray above, with a mottled gray face, a paler gray supercilium, and a blackish crown and nape. The white underparts are covered with fine gray barring, except on the unmarked throat. The longish tail is dark with three paler gray bands. Adult females are similar, but browner above with buffier underparts and browner barring below.
Immature birds come in two color morphs: the brown and the rufous
. Brown morph birds are dark sooty-brown above, finely barred with black, and white below, heavily barred with cinnamon. Rufous morph immatures are more chestnut above, and barred with rufous (rather than cinnamon) on the underparts. They also have duskier heads and brighter rufous tails than do brown morph birds.
The cere
and legs of all ages are yellow, and the bill, which is relatively heavy, is gray. Adults have red or red-brown irises, while those of immatures often are yellowish.
Unlike most accipiter
s, the Tiny Hawk's tail is quite short; it is squared or notched at the tip. Its wings are medium-length, with pointed tips, and its legs and toes are long.
down to western Ecuador
, northern Bolivia
, northern Argentina
, Paraguay
and southern Brazil
. They frequent humid and wet lowland
forest
s (including second growth) and forested foothills
from sea level to about 1800 meters (5900 ft), though most records come from elevations below 1000 m (3300 ft).
The species is believed to be fairly sedentary.
, though most often in the middle story. When hunting in low growth, it often flashes from one perch to another in rapid succession. It is a fast flier; instead of the typical flap-flap-glide cadence of the accipiters, it makes a few quick flaps and then briefly closes its wings before flapping again. Tiny Hawks occasionally soar above the forest canopy.
s, the Tiny Hawk feeds primarily on birds. It hunts hummingbirds and small passerine
s, typically darting out from a place of concealment to snatch them as they pass by, but also ambushing them when the smaller birds are perched. There is some evidence that it learns the regular perches of some hummingbirds and hunts for them there. Some individuals also hunt rodent
s.
may vary depending on their location; from Panama
to Colombia
, it apparently runs between February and June, while in the southern part of the range, it may range from October to January. They are known to build stick nest
s, at least sometimes in the canopy of tall tree
s. In Venezuela
, there is a record of a pair nesting in an old Black-collared Hawk
nest. Females lay one to three bluish-white eggs
, faintly streaked and spotted with brown. Incubation
and fledging periods are not known.
of the Tiny Hawk is a shrill, high-pitched, somewhat quavery series of 20–30 notes of uneven pitch. After an initial few accelerating notes, the call settles into a steady rhythm, variously transcribed as caucau-ca-ca-ca, keer-keer-keer or kree-ree-ree-ree.
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....
found in or near forests, primarily humid, throughout much of the Neotropics. It is primarily a bird-eater, and is known to prey on hummingbird
Hummingbird
Hummingbirds are birds that comprise the family Trochilidae. They are among the smallest of birds, most species measuring in the 7.5–13 cm range. Indeed, the smallest extant bird species is a hummingbird, the 5-cm Bee Hummingbird. They can hover in mid-air by rapidly flapping their wings...
s.
Usually named Accipiter superciliosus, it is the only 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...
of the genus
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...
Accipiter
Accipiter
The genus Accipiter is a group of birds of prey in the family Accipitridae, many of which are named as goshawks and sparrowhawks. They can be anatomically distinguished from their relatives by the lack of a procoracoid foramen. Two small and aberrant species usually placed here do possess a large...
yet studied which has a large procoracoid foramen
Foramen
In anatomy, a foramen is any opening. Foramina inside the body of humans and other animals typically allow muscles, nerves, arteries, veins, or other structures to connect one part of the body with another.-Skull:...
. It also differs from the typical sparrowhawk
Sparrowhawk
The Eurasian Sparrowhawk is a small bird of prey in the family Accipitridae. Adult male Eurasian Sparrowhawks have bluish grey upperparts and orange-barred underparts; females and juveniles are brown above with brown barring below...
s in other respects of its 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...
and in its DNA 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...
. Consequently, its old name Hieraspiza superciliosa may be more appropriate.
Taxonomy
There are two subspeciesSubspecies
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...
of Tiny Hawk, separated by the northern Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
. The two differ most significantly in relative tail length; differences in size and color are small, and can be hard to distinguish.
- A. s. superciliosus is found east of the Andes in South America. Slightly the larger of the two subspecies, it is paler and has diffuse, grayish barring on the underparts.
- A. s. fontanieri is found from NicaraguaNicaraguaNicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...
down to western EcuadorEcuadorEcuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
. It is somewhat smaller and darker than the nominate A. s. superciliosus, with a shorter tail and sharper, blacker barring below.
The Tiny Hawk and its sister species, the upland-dwelling Semi-collared Hawk ("A." collaris), form a superspecies
Superspecies
A superspecies is a group of at least two more or less distinctive species with approximately parapatric distributions. Not all species complexes, whether cryptices or ring species are superspecies, and vice versa, but many are...
.
Description
The Tiny Hawk is aptly named; males measure a mere 20 cm (eight inchInch
An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...
es, or about the size of a Turdus thrush), though females are slightly larger at 26.5 cm (10.5 in). It is one of the smallest true raptors in the world and is one of the smallest Accipiter
Accipiter
The genus Accipiter is a group of birds of prey in the family Accipitridae, many of which are named as goshawks and sparrowhawks. They can be anatomically distinguished from their relatives by the lack of a procoracoid foramen. Two small and aberrant species usually placed here do possess a large...
species, though the Little Sparrowhawk
Little Sparrowhawk
The Little Sparrowhawk is a species of bird of prey in the Accipitridae family. It is found in Angola, Botswana, Burundi, Democratic Republic of the Congo, Eritrea, Ethiopia, Kenya, Lesotho, Malawi, Mali, Mozambique, Namibia, Rwanda, Somalia, South Africa, Sudan, Swaziland, Tanzania, Uganda,...
of Africa is of similar or even smaller size. The birds range in weight from 75–120 g
Gram
The gram is a metric system unit of mass....
(0.17–0.26 lb
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...
). As with most raptors
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....
, there is considerable sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
in size, with females measuring 5–26 percent longer and as much as 60 percent heavier than males.
The adult male Tiny Hawk is dark slaty gray above, with a mottled gray face, a paler gray supercilium, and a blackish crown and nape. The white underparts are covered with fine gray barring, except on the unmarked throat. The longish tail is dark with three paler gray bands. Adult females are similar, but browner above with buffier underparts and browner barring below.
Immature birds come in two color morphs: the brown and the rufous
Rufous
Rufous is a colour that may be described as reddish-brown or brownish-red, as of rust or oxidised iron.The first recorded use of rufous as a colour name in English was in the year 1782....
. Brown morph birds are dark sooty-brown above, finely barred with black, and white below, heavily barred with cinnamon. Rufous morph immatures are more chestnut above, and barred with rufous (rather than cinnamon) on the underparts. They also have duskier heads and brighter rufous tails than do brown morph birds.
The cere
Cère
The Cère is a long river in south-western France, left tributary of the Dordogne River. Its source is in the south-western Massif Central, near the mountain Plomb du Cantal...
and legs of all ages are yellow, and the bill, which is relatively heavy, is gray. Adults have red or red-brown irises, while those of immatures often are yellowish.
Unlike most accipiter
Accipiter
The genus Accipiter is a group of birds of prey in the family Accipitridae, many of which are named as goshawks and sparrowhawks. They can be anatomically distinguished from their relatives by the lack of a procoracoid foramen. Two small and aberrant species usually placed here do possess a large...
s, the Tiny Hawk's tail is quite short; it is squared or notched at the tip. Its wings are medium-length, with pointed tips, and its legs and toes are long.
Habitat and distribution
Tiny Hawks are patchily distributed from eastern NicaraguaNicaragua
Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...
down to western Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
, northern Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
, northern Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, Paraguay
Paraguay
Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...
and southern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
. They frequent humid and wet lowland
Lowland
In physical geography, a lowland is any broad expanse of land with a general low level. The term is thus applied to the landward portion of the upward slope from oceanic depths to continental highlands, to a region of depression in the interior of a mountainous region, to a plain of denudation, or...
forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...
s (including second growth) and forested foothills
Foothills
Foothills are geographically defined as gradual increases in elevation at the base of a mountain range. They are a transition zone between plains and low relief hills to the adjacent topographically high mountains.-Examples:...
from sea level to about 1800 meters (5900 ft), though most records come from elevations below 1000 m (3300 ft).
The species is believed to be fairly sedentary.
Behavior
On clear mornings (and occasionally in late afternoons), the Tiny Hawk will sometimes sun itself on a high open branch. Occasionally, pairs will sun together. Otherwise, this is a secretive species and easily overlooked. It generally hunts from a perch, located anywhere from the undergrowth to the canopyCanopy (forest)
In biology, the canopy is the aboveground portion of a plant community or crop, formed by plant crowns.For forests, canopy also refers to the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms .Sometimes the term canopy is used to refer to the extent...
, though most often in the middle story. When hunting in low growth, it often flashes from one perch to another in rapid succession. It is a fast flier; instead of the typical flap-flap-glide cadence of the accipiters, it makes a few quick flaps and then briefly closes its wings before flapping again. Tiny Hawks occasionally soar above the forest canopy.
Diet
Like all accipiterAccipiter
The genus Accipiter is a group of birds of prey in the family Accipitridae, many of which are named as goshawks and sparrowhawks. They can be anatomically distinguished from their relatives by the lack of a procoracoid foramen. Two small and aberrant species usually placed here do possess a large...
s, the Tiny Hawk feeds primarily on birds. It hunts hummingbirds and small passerine
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
s, typically darting out from a place of concealment to snatch them as they pass by, but also ambushing them when the smaller birds are perched. There is some evidence that it learns the regular perches of some hummingbirds and hunts for them there. Some individuals also hunt rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s.
Breeding
Little is known about the Tiny Hawk's breeding biology. Their breeding seasonBreeding season
The breeding season is the most suitable season, usually with favourable conditions and abundant food and water, for breeding among some wild animals and birds . Species with a breeding season have naturally evolved to have sexual intercourse during a certain time of year in order to achieve the...
may vary depending on their location; from Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
to Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
, it apparently runs between February and June, while in the southern part of the range, it may range from October to January. They are known to build stick nest
Bird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
s, at least sometimes in the canopy of tall tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s. In Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
, there is a record of a pair nesting in an old Black-collared Hawk
Black-collared Hawk
The Black-collared Hawk is a species of bird of prey in the Accipitridae family. It is monotypic within the genus Busarellus....
nest. Females lay one to three bluish-white eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
, faintly streaked and spotted with brown. Incubation
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
and fledging periods are not known.
Vocalization
The callBird song
Bird vocalization includes both bird calls and bird songs. In non-technical use, bird songs are the bird sounds that are melodious to the human ear. In ornithology and birding, songs are distinguished by function from calls.-Definition:The distinction between songs and calls is based upon...
of the Tiny Hawk is a shrill, high-pitched, somewhat quavery series of 20–30 notes of uneven pitch. After an initial few accelerating notes, the call settles into a steady rhythm, variously transcribed as caucau-ca-ca-ca, keer-keer-keer or kree-ree-ree-ree.
External links
- Tiny Hawk videos on the Internet Bird Collection website
- Tiny Hawk photo gallery; Photo-High Res--(Close-up) on Visual Resources for Ornithology (VIREO) website
- Tiny Hawk photo on Surfbirds website
