Sharp-shinned hawk

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Sharp-shinned hawk
Accipiter striatus, Canet Road, San Luis Obispo 1.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Accipitridae
Genus: Accipiter
Species:
A. striatus
Binomial name
Accipiter striatus
Vieillot, 1808
Subspecies

A. s. chionogaster
A. s. erythronemius
A. s. fringilloides
A. s. madrensis
A. s. perobscurus
A. s. striatus
A. s. suttoni
A. s. velox
A. s. venator
A. s. ventralis

Contents

Accipiter striatus map.svg
  Breeding
  Year-round
  Nonbreeding
Synonyms

Accipiter velox

The sharp-shinned hawk (Accipiter striatus) or northern sharp-shinned hawk, commonly known as a sharpie, [2] is a small hawk, with males being the smallest hawks in the United States and Canada, but with the species averaging larger than some Neotropical species, such as the tiny hawk. The taxonomy is far from resolved, with some authorities considering the southern taxa to represent three separate species: white-breasted hawk (A. chionogaster), plain-breasted hawk (A. ventralis), and rufous-thighed hawk (A. erythronemius). [3] The American Ornithological Society and some other checklists keeps all four variations conspecific. [4]

Taxonomy

With a chick (nominate group) SharpshinnedHawk23.jpg
With a chick (nominate group)

The sharp-shinned hawk is sometimes separated into four species, with the northern group (see distribution) retaining both the scientific name and the common name: sharp-shinned hawk (A. striatus). [3] 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 allopatry combined with differences in plumage (see appearance) and, apparently, certain measurements, has been the background for the split, but hard scientific data are 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 specimens, also would be hard to prove due to the variability in the plumage of ventralis.

A 2021 of study of sharp-shinned hawks recommended recognising the three endemic Caribbean island subspecies as distinct species, based on analysis of nuclear and mitochondrial DNA and diagnosed by their plummage: A. striatus, restricted the island of Hispaniola, A. fringilloides to Cuba and A. venator to Puerto Rico. If this is accepted and A. striatus treated as endemic to Hispaniola, the continental complex would take the scientific name A. velox. [5]

Description

This is a small Accipiter hawk, with males 23 to 30 cm (9.1 to 11.8 in) long, with a wingspan of 42 to 58 cm (17 to 23 in) and weight from 82–115 g (2.9–4.1 oz). As common in Accipiter hawks, females are distinctly larger in size, averaging some 30% longer, and with a weight advantage of more than 50% being common. The female measures 29 to 37 cm (11 to 15 in) in length, has a wingspan of 58 to 68 cm (23 to 27 in) and weighs 150 to 219 g (5.3 to 7.7 oz). The wings measure 14.1–22.9 cm (5.6–9.0 in) each, the tail is 12–19 cm (4.7–7.5 in) long and the tarsus is 4.5–5.9 cm (1.8–2.3 in). Measurements given here are for the northern group, but they are comparable for the remaining subspecies. [6] Adults have short broad wings and a medium-length tail banded in blackish and gray with the tip varying among individuals from slightly notched [7] through square to slightly rounded (often narrowly tipped white). The remiges (typically only visible in flight) are whitish barred blackish. The legs are long and very slender (hence the common name) and yellow. The hooked bill is black and the cere is yellowish. The remaining plumage varies depending on group:

A juvenile sharp-shinned hawk in Parrish, Florida. Accipiter striatus Juvenile.jpg
A juvenile sharp-shinned hawk in Parrish, Florida.

Distribution

This species is widespread in North America, Central America, South America and the Greater Antilles. Below, the distributions of the four groups (see taxonomy) are described as they occur roughly from north to south:

Habitat

It occurs in a wide range of woodland and forest types, both dominated by conifers and by various types of broad-leaved trees (especially oaks) The largest populations of the nominate group (see taxonomy) are thought to occur in the temperate boreal forests, but winter in warmer regions farther 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 300–3,000 m (980–9,840 ft), but occasionally down to near sea-level and up to 4,000 m (13,000 ft). The taxon erythronemius (rufous-thighed hawk) is found in tropical and subtropical regions; both in lowlands and highlands.

Behaviour

Diet

Click for video of feeding sharp-shinned hawk Sharp-shinned hawk feeding with play button.jpg
Click for video of feeding sharp-shinned hawk

These birds surprise and capture most of their prey from cover or while flying quickly through dense vegetation. They are adept at navigating dense thickets, although this hunting method is often hazardous to the hawk. The great majority of this hawk's prey are small birds, especially various songbirds such as sparrows, wood-warblers, finches, wrens, nuthatches, tits, icterids and thrushes. Birds caught range in size from a 4.4 g (0.16 oz) Anna's hummingbird to a 577 g (1.272 lb) ruffed grouse and virtually any bird within this size range is potential prey. Typically, males will target smaller birds, such as sparrows and wood-warblers, and females will pursue larger prey, such as American robins and flickers, leading to a lack of conflict between the sexes for prey. These hawks often exploit backyard bird feeders in order to target congregations of ideal prey. They often pluck the feathers off their prey on a post or other perch. Rarely, sharp-shinned hawks will also eat rodents, lizards, frogs, snakes, and large insects, the latter typically being dragonflies captured on the wing during the hawk's migration. Bats have occasionally been recorded as a prey of this hawk. [8]

Female Sharp-shinned Hawk with prey (Starling).jpg

Reproduction

Immature (nominate group) Sharp-Shinned.jpg
Immature (nominate group)

Sharp-shinned hawks construct a stick nest in a large conifer or dense group of deciduous trees. Clutches of 3 to 8 eggs have been recorded, but 4 to 5 eggs is the typical clutch size. The eggs measure 37.6 mm × 30 mm (1.48 in × 1.18 in) and weigh about 19 g (0.67 oz). 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 prey. The young fledge at the age of about a month and rely on their parents for feeding and protection another four 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 American 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

Conservation

Endangered subspecies venator, endemic to Puerto Rico Puerto Rican Sharp-shinned hawk perched on tree limb.jpg
Endangered subspecies venator, endemic to Puerto Rico

In North America this species declined in numbers in the 1960s and 1970s, probably as a result of the use of DDT and other pesticides. The population of USA and Canada has rebounded since and might even exceed historical numbers today, probably due to the combination of the ban on DDT and the proliferation of backyard bird feeders in North America which create unnaturally reliable and easy prey sources. 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.

Related Research Articles

<span class="mw-page-title-main">Cooper's hawk</span> Species of bird

Cooper's hawk is a medium-sized hawk native to the North American continent and found from southern Canada to Mexico. This species is a member of the genus Accipiter, sometimes referred to as true hawks, which are famously agile, relatively small hawks common to wooded habitats around the world and also the most diverse of all diurnal raptor genera. As in many birds of prey, the male is smaller than the female. The birds found east of the Mississippi River tend to be larger on average than the birds found to the west. It is easily confused with the smaller but similar sharp-shinned hawk.

<i>Accipiter</i> Genus of birds

Accipiter is a genus of birds of prey in the family Accipitridae. With 49 recognized species it is the most diverse genus in its family. Most species are called goshawks or sparrowhawks, although with the exception of the American goshawk almost all New World species are simply known as "hawks". 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 procoracoid foramen and are also distinct as regards DNA sequence. They may warrant separation in the old genus Hieraspiza.

<span class="mw-page-title-main">Accipitrinae</span> Subfamily of birds

The Accipitrinae are the subfamily of the Accipitridae often known as the "true" hawks, including all members of Accipiter and the closely related genera Erythrotriorchis, and Megatriorchis. The large and widespread genus Accipiter includes goshawks, sparrowhawks, the sharp-shinned hawk and others. They are primarily woodland birds that hunt by sudden dashes from a concealed perch, with long tails, broad wings and high visual acuity facilitating this lifestyle. In light of recent genetic research, the kites of the traditional subfamily Milvinae may also belong to this group.

<span class="mw-page-title-main">Besra</span> Species of bird

The besra, also called the besra sparrowhawk, is a bird of prey in the family Accipitridae.

<span class="mw-page-title-main">Pale-breasted spinetail</span> Species of bird

The pale-breasted spinetail is a passerine bird in the Furnariinae subfamily of the ovenbird family Furnariidae. It is found in Costa Rica, Panama, Trinidad, and in every mainland South American country except Chile and Ecuador.

<span class="mw-page-title-main">White-throated hawk</span> Species of bird

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<span class="mw-page-title-main">Stripe-breasted spinetail</span> Species of bird

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<span class="mw-page-title-main">Bicolored hawk</span> Species of bird

The bicolored hawk is a species of bird of prey in the family Accipitridae. It is found in forest, woodland, second growth, plantations, and wooded savanna in southeastern Mexico, Central America, and northern and central South America. Though generally uncommon, it is the most common species of Accipiter in most of its range, but it does not occur at altitudes above 2,700 metres (8,900 ft) such as the highest parts of the Andes.

<span class="mw-page-title-main">Red-thighed sparrowhawk</span> Species of bird

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<span class="mw-page-title-main">Little sparrowhawk</span> Species of bird

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<span class="mw-page-title-main">Congo serpent eagle</span> Species of bird

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<span class="mw-page-title-main">Double-toothed kite</span> Species of bird

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<span class="mw-page-title-main">Plain-breasted hawk</span> Species of bird

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<span class="mw-page-title-main">Rufous-thighed hawk</span> Species of bird

The rufous-thighed hawk is a small hawk found from southern Brazil and southeastern Bolivia to Paraguay, Uruguay and northern Argentina. It is usually considered a subspecies of the sharp-shinned hawk by most taxonomists, including the American Ornithological Society, but the taxonomy is far from resolved, with some authorities considering the southern taxa to represent three separate species: white-breasted hawk, plain-breasted hawk, and rufous-thighed hawk.

<span class="mw-page-title-main">White-breasted hawk</span> Species of bird

The white-breasted hawk is a small hawk found from southern Mexico to Nicaragua. It is usually considered a subspecies of the sharp-shinned hawk by most taxonomists, including the American Ornithological Society, but the taxonomy is far from resolved, with some authorities considering the southern taxa to represent three separate species: white-breasted hawk, plain-breasted hawk, and rufous-thighed hawk.

References

  1. BirdLife International (2019). "Accipiter striatus". IUCN Red List of Threatened Species . 2019: e.T22734130A155416546. doi: 10.2305/IUCN.UK.2019-3.RLTS.T22734130A155416546.en . Retrieved 11 November 2021.
  2. https://birdfinding.info/sharp-shinned-hawk/
  3. 1 2 Gill, F.; Donsker, D.; Rasmussen, P. (eds.). "Hoatzin, New World vultures, Secretarybird, raptors". IOC World Bird List . 14.1. International Ornithological Congress. Retrieved 24 March 2024.
  4. Lepage, Denis (ed.). "Sharp-shinned Hawk Accipiter striatus Vieillot, LJP 1808". Avibase. Retrieved 24 March 2024.
  5. Catanach, Therese A.; Halley, Matthew R.; Allen, Julie M.; Johnson, Jeff A.; Thorstrom, Russell; Palhano, Samantha; Poor Thunder, Chyna; Gallardo, Julio C.; Weckstein, Jason D. (2021). "Systematics and conservation of an endemic radiation of Accipiter hawks in the Caribbean islands" (PDF). Ornithology. 138 (3). doi:10.1093/ornithology/ukab041.
  6. Raptors of the World by Ferguson-Lees, Christie, Franklin, Mead, and Burton. Houghton Mifflin (2001), ISBN   0-618-12762-3
  7. Chandler S. Robbins; Bertel Bruun; Herbert S. Zim (1983). Birds of North America: A Guide to Field Identification. Illustrations by Arthur Singer (Revised ed.). Golden Press. pp. 70–71. ISBN   0-307-37002-X.
  8. Mikula, P.; Morelli, F.; Lučan, R. K.; Jones, D. N.; Tryjanowski, P. (2016). "Bats as prey of diurnal birds: a global perspective". Mammal Review. 46 (3): 160–174. doi:10.1111/mam.12060.

Historical material