Sharp-shinned Hawk
Encyclopedia
The Sharp-shinned Hawk (Accipiter striatus) is a small hawk
. In fact, "sharp-shins" or "sharpies" (as they are sometimes casually called) are the smallest to reside in USA and Canada
, though some Neotropical species are smaller (notably the aptly named Tiny Hawk
). The taxonomy
is far from resolved, with some authorities considering the southern taxa three separate species: White-breasted Hawk (A. chionogaster), Plain-breasted Hawk (A. ventralis) and Rufous-thighed Hawk (A. erythronemius). See taxonomy for further on this.
, Central America
, South America
and the Greater Antilles
. Below the distributions of the four groups (see taxonomy) are described as they roughly occur from north to south:
It is commonly separated into four species. If split, the northern group (see distribution) retains both the scientific and the common name
: Sharp-shinned Hawk (A. striatus). In addition to the nominate taxon (A. s. striatus), it includes subspecies perobscurus, velox, suttoni, madrensis, fringilloides and venator. The three remaining taxa, each considered a monotypic
species if split, are the White-breasted Hawk (A. chionogaster; Kaup, 1852), Plain-breasted Hawk (A. ventralis; Sclater, 1866) and Rufous-thighed Hawk (A. erythronemius; Kaup, 1850). The breeding ranges of the groups are entirely allopatric, although the wintering range of the nominate group partially overlaps with the range of chionogaster (as is also the case with certain taxa within the nominate group). This combined with differences in plumage (see appearance) and, apparently, certain measurements, has been the background for the split, but hard scientific data is presently lacking (AOU
). Disregarding field guides, most material published in recent years (e.g. AOU, Ferguson-Lees et al. p. 586, and Dickinson et al.) has therefore considered all to be members of a single widespread species – but not without equivocation: Ferguson-Lees et al. say that if they were to make a world list, they would include the three taxa as separate species (p. 75), and the AOU's comment includes the note "split almost certainly good".
Storer (1952) suggested that the southernmost populations within the nominate group were paler below, thus approaching chionogaster. This has also been reflected in recent guides, where A. s. madrensis of southern Mexico is described as being relatively pale below (compared to more northern subspecies), but if this is a sign of intergradation
with chionogaster or a north-south cline which includes both the members of the nominate group and chionogaster remains unclear. In Bolivia, ventralis and erythronemius approach each other, but no evidence of intergradation is known – something that, without actual specimen
s, also would be hard to prove due to the variability in the plumage of ventralis.
It occurs in a wide range of woodland and forest types, both dominated by conifers and by various types of broad-leaved tree
s (especially oak
s) The largest populations of the nominate group (see taxonomy) are thought to occur in the temperate
boreal forests, but winter in warmer regions further south (see distribution). The taxa suttoni, madrensis (both from the nominate group), chionogaster (White-breasted Hawk) and ventralis (Plain-breasted Hawk), are found in upper tropical to temperate highlands; mainly at altitudes of 300–3000 m (1000–10000 ft), but occasionally down to near sea-level and up to 4000 m (13100 ft). The taxon erythronemius (Rufous-thighed Hawk) is found in tropical and subtropical regions; both in lowlands and highlands.
hawk. Males are 24 to 30 cm (9.5 to 12 in) long, have a wingspan of 52 to 58 cm (20 to 23 in) and weigh from 87 to 114 g (3.1 to 4 oz). As common in Accipiter hawks, females average distinctly larger at a length of 29 to 37 cm (11.5 to 14.5 in), a wingspan of 58 to 68 cm (23 to 27 in) and a weight of 150 to 218 g (5.3 to 7.7 oz). Measurements given here are for the northern group, but they are comparable for the remaining. Adults have short broad wings and a long square-ended tail banded in blackish and grey (often narrowly tipped white). The remiges (typically only visible in flight) are whitish barred blackish. Legs yellowish. The hooked bill is black and the cere
is yellowish. The remaining plumage varies depending on group:
s such as sparrow
s, wood-warblers and American Robin
s. Birds caught have ranged in size from a 4.4-g Anna's Hummingbird
to a 577-g (1.2-lb) Ruffed Grouse
and any bird within this size range is potential prey. Typically, males will target smaller birds, such as sparrow
s, and females will pursue larger prey, such as American Robins and flickers
. They often pluck the feathers off their prey on a post or other perch. Rarely, Sharp-shinned Hawks will also eat rodent
s, lizard
s, frog
s, snake
s, and large insect
s.
trees. Clutches of 3 to 8 eggs have been recorded, but are usually 4 to 5 eggs. The eggs measure 37.6 x 30 mm (1.48 x 1.18 in) and weigh about 19 g. The eggs are prized by egg-collectors, because they are heavily marked with surprisingly colorful and varied markings. The incubation period is thought to average at about 30 days. After hatching, the young are brooded for 16 to 23 days by the female, while the male defends the territory and catches food. The young fledge at about a month old and rely on their parents for feeding and protection another 4 weeks. The nesting sites and breeding behavior of Sharp-shinned Hawks are generally secretive, in order to avoid the predation of larger raptors, such as the Northern Goshawk and the Cooper's Hawk
. While in migration, adults are sometimes preyed on by most of the bird-hunting, larger raptors, especially the Peregrine Falcon
. The breeding behavior of the taxa chionogaster (White-breasted Hawk), ventralis (Plain-breasted Hawk) and erythronemius (Rufous-thighed Hawk) are comparably poorly known, but based on the available knowledge they appear to differ little from that of the nominate group.
and other pesticides. The population of USA and Canada has rebounded since and might even exceed historical numbers today. This is probably due to the combination of the ban on DDT and the proliferation of backyard birdfeeders in North America which create unnaturally reliable and easy prey for all Accipiter
s. Migratory Sharp-shinned Hawks are one of the most numerous raptors recorded at "hawk watches" across the country. An exception is the subspecies
from Puerto Rico
, Accipiter striatus venator, which is rare and listed as endangered by the U.S. Fish & Wildlife Service. The remaining resident subspecies from the Greater Antilles, fringilliodes from Cuba and nominate (A. s. striatus) from Hispaniola, are uncommon, local, and, at least in the case of the latter, decreasing. Both ventralis (Plain-breasted Hawk) and erythronemius (Rufous-thighed Hawk) are fairly common (but easily overlooked due to their secretive behavior) and presently considered safe. The situation for chionogaster (White-breasted Hawk) is potentially more problematic due to its limited range, although it, at least locally, remains fairly common.
Hawk
The term hawk can be used in several ways:* In strict usage in Australia and Africa, to mean any of the species in the subfamily Accipitrinae, which comprises the genera Accipiter, Micronisus, Melierax, Urotriorchis and Megatriorchis. The large and widespread Accipiter genus includes goshawks,...
. In fact, "sharp-shins" or "sharpies" (as they are sometimes casually called) are the smallest to reside in USA and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, though some Neotropical species are smaller (notably the aptly named Tiny Hawk
Tiny Hawk
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 hummingbirds....
). The taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
is far from resolved, with some authorities considering the southern taxa three separate species: White-breasted Hawk (A. chionogaster), Plain-breasted Hawk (A. ventralis) and Rufous-thighed Hawk (A. erythronemius). See taxonomy for further on this.
Distribution
This species is widespread in North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
, South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
and the Greater Antilles
Greater Antilles
The Greater Antilles are one of three island groups in the Caribbean. Comprising Cuba, Jamaica, Hispaniola , and Puerto Rico, the Greater Antilles constitute almost 90% of the land mass of the entire West Indies.-Greater Antilles in context :The islands of the Caribbean Sea, collectively known as...
. Below the distributions of the four groups (see taxonomy) are described as they roughly occur from north to south:
- The nominate (A. s. striatus) group is widespread in North AmericaNorth AmericaNorth America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, occurring throughout a large part of USA and Canada, except in the ice-covered regions of the far north. Populations in the northern part of the range migrateBird migrationBird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
south and spend the non-breeding season (winter) in southern USA, MexicoMexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and Central America as far south as PanamaPanamaPanama , 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...
, with a smaller number spending the winter in the Greater Antilles. Resident populations exists in temperateTemperateIn geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
parts of USA, CanadaCanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
(in a few coastal regions), Mexico (highlands from SonoraSonoraSonora officially Estado Libre y Soberano de Sonora is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided into 72 municipalities; the capital city is Hermosillo....
to OaxacaOaxacaOaxaca , , officially Estado Libre y Soberano de Oaxaca is one of the 31 states which, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided into 571 municipalities; of which 418 are governed by the system of customs and traditions...
), CubaCubaThe 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...
, HispaniolaHispaniolaHispaniola is a major island in the Caribbean, containing the two sovereign states of the Dominican Republic and Haiti. The island is located between the islands of Cuba to the west and Puerto Rico to the east, within the hurricane belt...
and Puerto RicoPuerto RicoPuerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
. - A. (s.) chionogaster (White-breasted Hawk) occurs in highlands from far southern Mexico (ChiapasChiapasChiapas officially Estado Libre y Soberano de Chiapas is one of the 31 states that, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 118 municipalities and its capital city is Tuxtla Gutierrez. Other important cites in Chiapas include San Cristóbal de las...
and OaxacaOaxacaOaxaca , , officially Estado Libre y Soberano de Oaxaca is one of the 31 states which, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided into 571 municipalities; of which 418 are governed by the system of customs and traditions...
), through HondurasHondurasHonduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...
, GuatemalaGuatemalaGuatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast...
and El SalvadorEl SalvadorEl Salvador or simply Salvador is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador; Santa Ana and San Miguel are also important cultural and commercial centers in the country and in all of Central America...
, to 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...
. It is, as far as known, resident, but some local movements may occur. - A. (s.) ventralis (Plain-breasted Hawk) occurs in the coastal mountains of northern VenezuelaVenezuelaVenezuela , 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...
and ColombiaColombiaColombia, 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...
, south through the AndesAndesThe 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...
from western Venezuela, through Colombia, 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...
and PeruPeruPeru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
, to central BoliviaBoliviaBolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
. A disjunctDisjunct distributionIn biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically...
population occurs in the TepuiTepuiA tepui , or tepuy, is a table-top mountain or mesa found in the Guiana Highlands of South America, especially in Venezuela. The word tepui means "house of the gods" in the native tongue of the Pemon, the indigenous people who inhabit the Gran Sabana....
s of southern Venezuela (likely to extend into adjacent parts of RoraimaRoraimaRoraima is the northernmost and least populated state of Brazil, located in the Amazon region. It borders the states of Amazonas and Pará, as well as the nations of Venezuela and Guyana. The population is 400,000 and the capital is Boa Vista...
in far northern BrazilBrazilBrazil , 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...
, but this remains unconfirmed). It is, as far as known, resident, but some local movements may occur. - A. (s.) erythronemius (Rufous-thighed Hawk) is widespread in eastern South AmericaSouth AmericaSouth America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
in eastern and southern Brazil, UruguayUruguayUruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
, ParaguayParaguayParaguay , 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...
, north-eastern ArgentinaArgentinaArgentina , 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...
and south-eastern Bolivia. It is, as far as known, resident in some regions and migratory in others. The movements are generally poorly understood, but it only occurs seasonally at some localities in Argentina.
Taxonomy
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
: Sharp-shinned Hawk (A. striatus). In addition to the nominate taxon (A. s. striatus), it includes subspecies perobscurus, velox, suttoni, madrensis, fringilloides and venator. The three remaining taxa, each considered a monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
species if split, are the White-breasted Hawk (A. chionogaster; Kaup, 1852), Plain-breasted Hawk (A. ventralis; Sclater, 1866) and Rufous-thighed Hawk (A. erythronemius; Kaup, 1850). The breeding ranges of the groups are entirely allopatric, although the wintering range of the nominate group partially overlaps with the range of chionogaster (as is also the case with certain taxa within the nominate group). This combined with differences in plumage (see appearance) and, apparently, certain measurements, has been the background for the split, but hard scientific data is presently lacking (AOU
American Ornithologists' Union
The American Ornithologists' Union is an ornithological organization in the USA. Unlike the National Audubon Society, its members are primarily professional ornithologists rather than amateur birders...
). Disregarding field guides, most material published in recent years (e.g. AOU, Ferguson-Lees et al. p. 586, and Dickinson et al.) has therefore considered all to be members of a single widespread species – but not without equivocation: Ferguson-Lees et al. say that if they were to make a world list, they would include the three taxa as separate species (p. 75), and the AOU's comment includes the note "split almost certainly good".
Storer (1952) suggested that the southernmost populations within the nominate group were paler below, thus approaching chionogaster. This has also been reflected in recent guides, where A. s. madrensis of southern Mexico is described as being relatively pale below (compared to more northern subspecies), but if this is a sign of intergradation
Intergradation
In zoology, intergradation is the way in which two distinct subspecies are connected via areas where populations are found that have the characteristics of both...
with chionogaster or a north-south cline which includes both the members of the nominate group and chionogaster remains unclear. In Bolivia, ventralis and erythronemius approach each other, but no evidence of intergradation is known – something that, without actual specimen
Specimen
A specimen is a portion/quantity of material for use in testing, examination, or study.BiologyA laboratory specimen is an individual animal, part of an animal, a plant, part of a plant, or a microorganism, used as a representative to study the properties of the whole population of that species or...
s, also would be hard to prove due to the variability in the plumage of ventralis.
Habitat
Broad-leaved tree
A broad-leaved tree or broad-leaf tree or broadleaf tree is any tree that has wide leaves, rather than slim, needle-like leaves as found in conifers...
s (especially oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
s) The largest populations of the nominate group (see taxonomy) are thought to occur in the temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
boreal forests, but winter in warmer regions further south (see distribution). The taxa suttoni, madrensis (both from the nominate group), chionogaster (White-breasted Hawk) and ventralis (Plain-breasted Hawk), are found in upper tropical to temperate highlands; mainly at altitudes of 300–3000 m (1000–10000 ft), but occasionally down to near sea-level and up to 4000 m (13100 ft). The taxon erythronemius (Rufous-thighed Hawk) is found in tropical and subtropical regions; both in lowlands and highlands.
Appearance
A small 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...
hawk. Males are 24 to 30 cm (9.5 to 12 in) long, have a wingspan of 52 to 58 cm (20 to 23 in) and weigh from 87 to 114 g (3.1 to 4 oz). As common in Accipiter hawks, females average distinctly larger at a length of 29 to 37 cm (11.5 to 14.5 in), a wingspan of 58 to 68 cm (23 to 27 in) and a weight of 150 to 218 g (5.3 to 7.7 oz). Measurements given here are for the northern group, but they are comparable for the remaining. Adults have short broad wings and a long square-ended tail banded in blackish and grey (often narrowly tipped white). The remiges (typically only visible in flight) are whitish barred blackish. Legs yellowish. The hooked bill is black and 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...
is yellowish. The remaining plumage varies depending on group:
- Nominate group: Cap dark and upperparts blue-grey (the former darker). Often, a few more or less random white spots can be seen on the back. Underparts white with rufous or tawnyTawny (color)Tawny is a yellowish brown color. The word means "tan-colored," from Anglo-Norman tauné "associated with the brownish-yellow of tanned leather," from Old French tané "to tan hides," from Medieval Latin tannare, from tannum "crushed oak bark," used in tanning leather, probably from a Celtic source...
bars. Crissum white. Thighs rufous, but often barred white. The cheeks are tinged rufous (sometimes faint, but generally very distinct in taxa from the Greater Antilles). The iridesIris (anatomy)The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
are dark orange to red, but these are yellowish to pale orange in juvenilesJuvenile (organism)A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
. Juveniles have dark brownish upperparts with each feather edged rufous, giving a rather scaly appearance. The brown head is streaked whitish, and the whitish underparts are extensively streaked brown.
- A. (s.) chionogaster (White-breasted Hawk): Resembles the members of the nominate group, but upperparts darker (often appears almost black), thighs whitish-buff and underparts and cheeks entirely white. Juveniles with darker upperparts and distinctly finer streaking below than juveniles of the nominate group.
- A. (s.) ventralis (Plain-breasted Hawk): PolymorphicPolymorphism (biology)Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...
. The most common morph has dark grey upperparts (often appears almost black) and white underparts variable barred, shaded or mottled with rufous or tawny-buffBuff (colour)Buff is a pale yellow-brown colour that got its name from the colour of buff leather.Displayed on the right is the colour buff.EtymologyAccording to the Oxford English Dictionary, buff as a descriptor of a colour was first used in the London Gazette of 1686, describing a uniform to be "A Red Coat...
(extensively marked individuals may appear almost entirely rufous or tawny-buff below). Occasionally, the barring to the lower belly and flanks may appear duskier. The white morph has bluish-grey upperparts (similar to the nominate group), but its underparts are all white except for its rufous thighs. The rare dark morph, the only morph which sometimes lacks rufous thighs, is entirely sooty (occasionally with slight white barring to belly and faint grey bands in tail). The underparts of the females average paler than males of the same morph. The iris is typically yellow (contra illustrations in some books), but individuals (mainly sub-adults?) with a darker iris are occasionally seen. Juveniles have dark brownish or dusky upperparts with each feather typically edged rufous, giving a rather scaly appearance. The underparts are white streaked brown, and the thighs are rufous barred white. Occasionally, juveniles with underparts extensively rufous streaked blackish are seen. - A. (s.) erythronemius (Rufous-thighed Hawk): Resembles the nominate group, but upperparts darker, streaking to underparts rufous or dusky, cheeks typically with a clear rufous patch (occasionally lacking almost entirely) and iris yellow (contra illustrations in some books). Juveniles resemble juveniles of the nominate group, but streaking to underparts typically restricted to throat and central underparts, with flanks scaled or barred (often also belly).
Identification
- The northern group is easily mistaken for the slightly larger and lankier Cooper's HawkCooper's HawkCooper's Hawk is a medium-sized hawk native to the North American continent and found from Canada to Mexico. As in many birds of prey, the male is smaller than the female...
, which match the Sharp-shinned in plumage. In flight, the Cooper's, with its longer wings and larger head, is sometimes compared to a "flying cross"; whereas the broader-winged and smaller-headed Sharp-shinned is described as a "flying mallet".
- A. (s.) chionogaster (White-breasted Hawk) is generally easily recognized by its white underparts. Juv. Bicolored Hawk, juv. Barred Forest Falcon and Collared Forest Falcon generally occur below the altitude of chionogaster, and they have whitish or buff nuchal collars. Juv. Double-toothed KiteDouble-toothed KiteThe Double-toothed Kite is a species of bird of prey in the Accipitridae family. It is found in Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, Trinidad and Tobago, and Venezuela.This fairly...
and certain 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...
hawks (e.g. Short-tailed HawkShort-tailed HawkThe Short-tailed Hawk is an American bird of prey in the family Accipitridae, which also includes the eagles and Old World vultures. As a member of the genus Buteo, it is not a true hawk and thus also referred to as a "buteo" or "buzzard". The White-throated Hawk The Short-tailed Hawk (Buteo...
) may show a vaguely similar pattern, but are very differently shaped.
- A. (s.) ventralis (Plain-breasted Hawk), while itself very variable in plumage, is generally easily recognized by the Accipiter shape and the colour of the underparts. The grey underparts of the Bicolored Hawk are not duplicated by any plumage of ventralis and juv. Bicoloured (which may be whitish below) has a nuchal collar. The smaller Tiny Hawk mainly occurs in lowlands, is very small and lacks the rufous thighs of ventralis. The rare dark morph ventralis is arguably the plumage most likely to cause confusion with other species (e.g. White-rumped HawkWhite-rumped HawkThe White-rumped Hawk is a species of bird of prey in the Accipitridae family.It is found in Argentina, Bolivia, Brazil, Colombia, Ecuador, Paraguay, Peru, and Venezuela....
, dark morph Collared Forest Falcon and various Buteo hawks), but the yellow eyes and the overall shape means that it too is relatively distinctive.
- A. (s.) erythronemius (Rufous-thighed Hawk) is distinctive within its range, but commonly confused with the Roadside HawkRoadside HawkThe Roadside Hawk is a relatively small bird of prey found in Latin America. This vocal species is often the most common raptor in its range. It has many subspecies and is sometimes placed in the monotypic genus Rupornis instead of Buteo.-Description:The Roadside Hawk is long and weighs...
(with a very different shape). The Bicolored Hawk is the only other Accipiter within the range of erythronemius which may show yellow eyes and rufous thighs, but it has a different pattern below.
Food and hunting
These birds surprise and capture all their prey from cover or while flying quickly through dense vegetation. They are adept at navigating dense thickets. The great majority of this hawk's prey is small birds, especially various songbirdSongbird
A songbird is a bird belonging to the suborder Passeri of the perching birds . Another name that is sometimes seen as scientific or vernacular name is Oscines, from Latin oscen, "a songbird"...
s such as sparrow
Sparrow
The sparrows are a family of small passerine birds, Passeridae. They are also known as true sparrows, or Old World sparrows, names also used for a genus of the family, Passer...
s, wood-warblers and American Robin
American Robin
The American Robin or North American Robin is a migratory songbird of the thrush family. It is named after the European Robin because of its reddish-orange breast, though the two species are not closely related, with the European robin belonging to the flycatcher family...
s. Birds caught have ranged in size from a 4.4-g Anna's Hummingbird
Anna's Hummingbird
Anna's Hummingbird is a medium-sized hummingbird native to the west coast of North America. This bird was named after Anna Masséna, Duchess of Rivoli.-Description:...
to a 577-g (1.2-lb) Ruffed Grouse
Ruffed Grouse
The Ruffed Grouse is a medium-sized grouse occurring in forests from the Appalachian Mountains across Canada to Alaska. It is non-migratory.The Ruffed Grouse is frequently referred to as a "partridge"...
and any bird within this size range is potential prey. Typically, males will target smaller birds, such as sparrow
Sparrow
The sparrows are a family of small passerine birds, Passeridae. They are also known as true sparrows, or Old World sparrows, names also used for a genus of the family, Passer...
s, and females will pursue larger prey, such as American Robins and flickers
Colaptes
Colaptes is the genus of woodpeckers which contains the flickers. The scientific name means "the pecker", Latinized from the Greek verb kolápto , "to peck"....
. They often pluck the feathers off their prey on a post or other perch. Rarely, Sharp-shinned Hawks will also eat 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, lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
s, frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
s, snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
s, and large insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s.
Reproduction
Sharp-shinned Hawks will construct a stick nest in a large conifer or dense group of deciduousDeciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
trees. Clutches of 3 to 8 eggs have been recorded, but are usually 4 to 5 eggs. The eggs measure 37.6 x 30 mm (1.48 x 1.18 in) and weigh about 19 g. The eggs are prized by egg-collectors, because they are heavily marked with surprisingly colorful and varied markings. The incubation period is thought to average at about 30 days. After hatching, the young are brooded for 16 to 23 days by the female, while the male defends the territory and catches food. The young fledge at about a month old and rely on their parents for feeding and protection another 4 weeks. The nesting sites and breeding behavior of Sharp-shinned Hawks are generally secretive, in order to avoid the predation of larger raptors, such as the Northern Goshawk and the Cooper's Hawk
Cooper's Hawk
Cooper's Hawk is a medium-sized hawk native to the North American continent and found from Canada to Mexico. As in many birds of prey, the male is smaller than the female...
. While in migration, adults are sometimes preyed on by most of the bird-hunting, larger raptors, especially the Peregrine Falcon
Peregrine Falcon
The Peregrine Falcon , also known as the Peregrine, and historically as the Duck Hawk in North America, is a widespread bird of prey in the family Falconidae. A large, crow-sized falcon, it has a blue-gray back, barred white underparts, and a black head and "moustache"...
. The breeding behavior of the taxa chionogaster (White-breasted Hawk), ventralis (Plain-breasted Hawk) and erythronemius (Rufous-thighed Hawk) are comparably poorly known, but based on the available knowledge they appear to differ little from that of the nominate group.
Conservation
In North America this bird declined in numbers in the 1960s and 1970s, probably as a result of the use of DDTDDT
DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....
and other pesticides. The population of USA and Canada has rebounded since and might even exceed historical numbers today. This is probably due to the combination of the ban on DDT and the proliferation of backyard birdfeeders in North America which create unnaturally reliable and easy prey for all 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. Migratory Sharp-shinned Hawks are one of the most numerous raptors recorded at "hawk watches" across the country. An exception is the 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...
from Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
, Accipiter striatus venator, which is rare and listed as endangered by the U.S. Fish & Wildlife Service. The remaining resident subspecies from the Greater Antilles, fringilliodes from Cuba and nominate (A. s. striatus) from Hispaniola, are uncommon, local, and, at least in the case of the latter, decreasing. Both ventralis (Plain-breasted Hawk) and erythronemius (Rufous-thighed Hawk) are fairly common (but easily overlooked due to their secretive behavior) and presently considered safe. The situation for chionogaster (White-breasted Hawk) is potentially more problematic due to its limited range, although it, at least locally, remains fairly common.
External links
- Sharp-shinned Hawk - Cornell Lab of Ornithology
- Sharp-shinned Hawk - USGS Patuxent Bird Identification InfoCenter
- picture of Sharp-shinned Hawk (Juvenile male)in the hand
- Sharp-shinned Hawk Wing & Weight data
- Sharp-shinned Hawk Information and Photos - South Dakota Birds and Birding
- Information and photos of Accipiter (striatus) chionogaster - Mayanbirding.
- Information and photo of Accipiter (striatus) chionogaster - the Peregrine Fund.
- Information and photo of Accipiter (striatus) erythronemius - the Peregrine Fund.
- Information and photo of Accipiter (striatus) ventralis - the Peregrine Fund.