Falco Sparverius
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The American kestrel (''Falco sparverius'') is the smallest and most common
falcon Falcons () are birds of prey in the genus ''Falco'', which includes about 40 species. Some small species of falcons with long, narrow wings are called hobbies, and some that hover while hunting are called kestrels. Falcons are widely distrib ...
in North America. Though it has been called the American sparrowhawk, this common name is a misnomer; the American kestrel is a true falcon, while neither the
Eurasian sparrowhawk The Eurasian sparrowhawk (''Accipiter nisus''), also known as the northern sparrowhawk or simply the sparrowhawk, is a small bird of prey in the family Accipitridae. Adult male Eurasian sparrowhawks have bluish grey upperparts and orange-barred ...
nor the other species called sparrowhawks are in the '' Falco'' genus, hence genetically unrelated to the American kestrel. It has a roughly two-to-one range in size over subspecies and sex, varying in size from about the weight of a
blue jay The blue jay (''Cyanocitta cristata'') is a passerine bird in the family Corvidae, native to eastern North America. It lives in most of the eastern and central United States; some eastern populations may be migratory. Resident populations ar ...
to a
mourning dove The mourning dove (''Zenaida macroura'') is a member of the dove Family (biology), family, Columbidae. The bird is also known as the American mourning dove, the rain dove, the chueybird, colloquially as the turtle dove, and it was once known a ...
. It also ranges to South America and is a well-established species that has evolved into 17 subspecies adapted to different environments and habitats throughout the Americas. It exhibits
sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
in size (females being moderately larger) and
plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
, although both sexes have a
rufous Rufous () is a color that may be described as reddish-brown or brownish- red, as of rust or oxidised iron. The first recorded use of ''rufous'' as a color name in English was in 1782. However, the color is also recorded earlier in 1527 as a d ...
back with noticeable barring. Its plumage is colorful and attractive, and juveniles are similar in plumage to adults. The American kestrel usually hunts in energy-conserving fashion by perching and scanning the ground for prey to ambush, though it also hunts from the air. It sometimes hovers in the air with rapid wing beats while homing in on prey. Its diet typically consists of
grasshopper Grasshoppers are a group of insects belonging to the suborder Caelifera. They are amongst what are possibly the most ancient living groups of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago. Grassh ...
s and other insects,
lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...
s, mice, and small birds (e.g.
sparrows Sparrow may refer to: Birds * Old World sparrows, family Passeridae ** House sparrow, or ''Passer domesticus'' * New World sparrows, family Passerellidae * two species in the Passerine family Estrildidae: ** Java sparrow ** Timor sparrow * Hed ...
). This broad diet has contributed to its wide success as a species. It nests in cavities in trees, cliffs, buildings, and other structures. The female lays three to seven eggs, which both sexes help to incubate. Its breeding range extends from central and western
Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
across northern Canada to
Nova Scotia Nova Scotia is a Provinces and territories of Canada, province of Canada, located on its east coast. It is one of the three Maritime Canada, Maritime provinces and Population of Canada by province and territory, most populous province in Atlan ...
, and south throughout North America, into central
Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
and the
Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...
. It is a local breeder in Central America and is widely distributed throughout South America. Most birds breeding in Canada and the northern United States
migrate Migration, migratory, or migrate may refer to: Human migration * Human migration, physical movement by humans from one region to another ** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...
south in the winter. It is an occasional vagrant to Western Europe. Based on appearance and behavior it was for many years considered a member of the primarily European and African kestrel
clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
within the genus ''Falco'', but DNA analysis shows the American kestrel to actually be genetically more closely related to the larger American falcons such as the peregrine,Wink, M., and H. Sauer-Gürth (2004) "Phylogenetic relationships in diurnal raptors based on nucleotide sequences of mitochondrial and nuclear marker genes", pp. 483–498 in R.D. Chancellor and B.-U. Meyburg (eds.) ''Raptors Worldwide'', World Working Group on Birds of Prey, Berlin. aplomado, and
prairie falcon The prairie falcon (''Falco mexicanus'') is a medium-sized Falconiformes, falcon found in Western North America. A separate species from the peregrine falcon, with which it shares some visual similarities, the prairie falcon is, essentially, an ...
s. Though the species has not been renamed as a result of these genetic analyses, it is not actually a
kestrel The term kestrel (from , derivative from , i.e. ratchet) is the common name given to several species of predatory birds from the falcon genus ''Falco''. Kestrels are most easily distinguished by their typical hunting behaviour which is to hover ...
in the
phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...
sense. Instead, a process of
convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...
to fit a similar small prey niche in the ecosystem as the true kestrels have left it with similar physical characteristics and hunting methods. The American kestrel is a common bird used in
falconry Falconry is the hunting of wild animals in their natural state and habitat by means of a trained bird of prey. Small animals are hunted; squirrels and rabbits often fall prey to these birds. Two traditional terms are used to describe a person ...
, especially by beginners. Though not as strong a flyer as many other, larger falcons, proper training and weight control by the falconer allows many American kestrels to become effective hunters of birds in the size range of sparrows and starlings, with occasional success against birds up to approximately twice their own weight.


Taxonomy

The American kestrel was
formally described A species description is a formal scientific description of a newly encountered species, typically articulated through a scientific publication. Its purpose is to provide a clear description of a new species of organism and explain how it differ ...
in 1758 by the Swedish naturalist
Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
in the tenth edition of his ''
Systema Naturae ' (originally in Latin written ' with the Orthographic ligature, ligature æ) is one of the major works of the Sweden, Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the syste ...
'' under the current
binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...
''Falco sparverius''. Linnaeus based his account on the "little hawk" that had been described and illustrated by the English naturalist
Mark Catesby Mark Catesby (24 March 1683 – 23 December 1749) was an English natural history, naturalist who studied the flora and fauna of the New World. Between 1729 and 1747, Catesby published his ''Natural History of Carolina, Florida and the Bahama ...
in his book ''The Natural History of Carolina, Florida and the Bahama Islands'' that was published between 1729 and 1732. Linnaeus specified the type locality as America but this was restricted to South Carolina based on Catesby. The genus name is from
Late Latin Late Latin is the scholarly name for the form of Literary Latin of late antiquity.Roberts (1996), p. 537. English dictionary definitions of Late Latin date this period from the 3rd to 6th centuries CE, and continuing into the 7th century in ...
meaning "falcon". The specific epithet ''sparverius'' is
Medieval Latin Medieval Latin was the form of Literary Latin used in Roman Catholic Church, Roman Catholic Western Europe during the Middle Ages. It was also the administrative language in the former Western Roman Empire, Roman Provinces of Mauretania, Numidi ...
for a "sparrowhawk". Until the sixth edition of the AOU Checklist of North American Birds was published by the
American Ornithologists' Union The American Ornithological Society (AOS) is an ornithological organization based in the United States. The society was formed in October 2016 by the merger of the American Ornithologists' Union (AOU) and the Cooper Ornithological Society. Its ...
in 1983, the most commonly used name for the American kestrel was the ''sparrow hawk''. This was due to a mistaken connection with the
Eurasian sparrowhawk The Eurasian sparrowhawk (''Accipiter nisus''), also known as the northern sparrowhawk or simply the sparrowhawk, is a small bird of prey in the family Accipitridae. Adult male Eurasian sparrowhawks have bluish grey upperparts and orange-barred ...
in the genus ''
Accipiter ''Accipiter'' () is a genus of birds of prey in the family Accipitridae. Some species are called sparrowhawks, but there are many sparrowhawks in other genera such as '' Tachyspiza''. These birds are slender with short, broad, rounded wings and ...
''. The sixth edition of the AOU Checklist corrected this, officially renaming the bird ''American kestrel''. Several other colloquial names for the kestrel are also in use, including ''grasshopper hawk'', due to its diet, and ''killy hawk'', due to its distinct call. Wauer, p. 4 As noted in the introduction, DNA analysis shows the American kestrel to actually be genetically more closely related to the larger American falcons than to the true kestrels. However, based on its physical similarity to the kestrels and the established nature of the name American kestrel, there has been little impetus to change its name. This could change in the future if continued genetic research more precisely determines the evolutionary history of the American kestrel within the genus ''Falco''. The entire genus is actually a set of species so closely related that most or all can be hybridized by artificial insemination. Significant natural hybridization of species has occurred in the past during the evolution of this closely related set of species, such that precise evolutionary genetic analysis as to which species are more basal to other species or to the genus as a whole is difficult to render. Seventeen subspecies of the American kestrel are recognized, generally based upon plumage, size, and vocalizations: *''F. s. sparverius'', described by
Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
in
1758 Events January–March * January 1 – Swedish biologist Carl Linnaeus (Carl von Linné) publishes in Stockholm the first volume (''Animalia'') of the 10th edition of ''Systema Naturae'', the starting point of modern zoologic ...
, is the
nominate subspecies In biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. ...
. It is found in most of the United States, Canada and Mexico. *''F. s. paulus'', described by Howe and King in 1902, is found in the southeastern United States from
Louisiana Louisiana ( ; ; ) is a state in the Deep South and South Central regions of the United States. It borders Texas to the west, Arkansas to the north, and Mississippi to the east. Of the 50 U.S. states, it ranks 31st in area and 25 ...
to Florida. *''F. s. peninsularis'', described by
Edgar Alexander Mearns Edgar Alexander Mearns (September 11, 1856 – November 1, 1916) was an American surgeon, ornithologist and field naturalist. He was a founder of the American Ornithologists' Union. Life Mearns was born in Highland Falls, New York, to Alexa ...
in 1892, is found in southern
Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...
. *''F. s. tropicalis'', described by
Ludlow Griscom Ludlow Griscom (June 17, 1890 – May 28, 1959) was an American ornithologist known as a pioneer in field ornithology. His emphasis on the identification of free-flying birds by field marks became widely adopted by professionals and amateurs. M ...
in 1930, is found from southern Mexico to northern
Honduras Honduras, officially the Republic of Honduras, is a country in Central America. It is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Ocean at the Gulf of Fonseca, ...
. *''F. s. nicaraguensis'', described by Howell in 1965, is found in Honduras and
Nicaragua Nicaragua, officially the Republic of Nicaragua, is the geographically largest Sovereign state, country in Central America, comprising . With a population of 7,142,529 as of 2024, it is the third-most populous country in Central America aft ...
. *''F. s. sparveroides'', described by
Nicholas Aylward Vigors Nicholas Aylward Vigors (1785 – 26 October 1840) was an Ireland, Irish zoologist and politician. He popularized the classification of birds on the basis of the quinarian system. Early life Vigors was born at Old Leighlin, County Carlow, in 1 ...
in 1827, is found on
Cuba Cuba, officially the Republic of Cuba, is an island country, comprising the island of Cuba (largest island), Isla de la Juventud, and List of islands of Cuba, 4,195 islands, islets and cays surrounding the main island. It is located where the ...
, Isla de Juventud and the central and southern
Bahamas The Bahamas, officially the Commonwealth of The Bahamas, is an archipelagic and island country within the Lucayan Archipelago of the Atlantic Ocean. It contains 97 per cent of the archipelago's land area and 88 per cent of its population. ...
. *''F. s. dominicensis'', described by
Johann Friedrich Gmelin Johann Friedrich Gmelin (8 August 1748 – 1 November 1804) was a German natural history, naturalist, chemist, botanist, entomologist, herpetologist, and malacologist. Education Johann Friedrich Gmelin was born as the eldest son of Philipp F ...
in 1788, is found on
Hispaniola Hispaniola (, also ) is an island between Geography of Cuba, Cuba and Geography of Puerto Rico, Puerto Rico in the Greater Antilles of the Caribbean. Hispaniola is the most populous island in the West Indies, and the second-largest by List of C ...
(both the
Dominican Republic The Dominican Republic is a country located on the island of Hispaniola in the Greater Antilles of the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean. It shares a Maritime boundary, maritime border with Puerto Rico to the east and ...
and
Haiti Haiti, officially the Republic of Haiti, is a country on the island of Hispaniola in the Caribbean Sea, east of Cuba and Jamaica, and south of the Bahamas. It occupies the western three-eighths of the island, which it shares with the Dominican ...
) and
Jamaica Jamaica is an island country in the Caribbean Sea and the West Indies. At , it is the third-largest island—after Cuba and Hispaniola—of the Greater Antilles and the Caribbean. Jamaica lies about south of Cuba, west of Hispaniola (the is ...
. *''F. s. caribaearum'', described by Gmelin in 1788, is found on
Puerto Rico ; abbreviated PR), officially the Commonwealth of Puerto Rico, is a Government of Puerto Rico, self-governing Caribbean Geography of Puerto Rico, archipelago and island organized as an Territories of the United States, unincorporated territo ...
and throughout the
Lesser Antilles The Lesser Antilles is a group of islands in the Caribbean Sea, forming part of the West Indies in Caribbean, Caribbean region of the Americas. They are distinguished from the larger islands of the Greater Antilles to the west. They form an arc w ...
to
Grenada Grenada is an island country of the West Indies in the eastern Caribbean Sea. The southernmost of the Windward Islands, Grenada is directly south of Saint Vincent and the Grenadines and about north of Trinidad and Tobago, Trinidad and the So ...
. *''F. s. brevipennis'', described by
Hans von Berlepsch Count Hans Hermann Carl Ludwig von Berlepsch (29 July 1850 – 27 February 1915) was a German ornithologist who took an interest in the birds of South America. He also had a cousin named Baron Sittich Hans von Berlepsch (1857-1933) with whom he w ...
in 1892, is found in the
Netherlands Antilles The Netherlands Antilles (, ; ), also known as the Dutch Antilles, was a constituent Caribbean country of the Kingdom of the Netherlands consisting of the islands of Saba (island), Saba, Sint Eustatius, and Sint Maarten in the Lesser Antilles, ...
. *''F. s. isabellinus'', described by
William Swainson William Swainson Fellow of the Linnean Society, FLS, Fellow of the Royal Society, FRS (8 October 1789 – 6 December 1855), was an English ornithologist, Malacology, malacologist, Conchology, conchologist, entomologist and artist. Life Swains ...
in 1837, is found from
Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...
to northern
Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
. *''F. s. ochraceus'', described by Charles B. Cory in 1915, is found in eastern
Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...
and northwestern
Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...
. *''F. s. caucae'', described by Frank Chapman in 1915, is found in western Colombia. *''F. s. aequatorialis'', described by Mearns in 1892, is found in northern
Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...
. *''F. s. peruvianus'', described by Cory in 1915, is found in southwestern Ecuador,
Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
and northern
Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...
. *''F. s. fernandensis'', described by Chapman in 1915, is found on the
Juan Fernández Islands The Juan Fernández Islands () are a sparsely inhabited series of islands in the South Pacific Ocean, reliant on tourism and fishing. Situated off the coast of Chile, they are composed of three main volcanic islands: Robinson Crusoe Island, R ...
off Chile. *''F. s. cinnamominus'', described by Swainson in 1837, is found in Peru, Chile and
Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...
. *''F. s. cearae'', described by Cory in 1915, is found from northeastern Brazil south to eastern
Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...
.


Description

Under traditional classification, the American kestrel is the smallest raptor in America. The American kestrel is sexually dimorphic, although there is some overlap in plumage coloration between the sexes. The bird ranges from in length with a wingspan of . The female kestrel is larger than the male, though less so than larger falcons, being typically about 10% to 15% larger within a subspecies. The more northern subspecies tend to larger sizes (northern hemisphere), with a large northern female being about twice the size of a small southern male. The male typically weighs , and the female . In standard measurements, the wing bone is long, the tail is and the tarsus is . Physically, American kestrels are leaner and less muscular than larger falcons.Mullenix, Matt (2003
Merlins and American Kestrels Compared
merlinfalconry.com.
The pectoral flight muscles of the American kestrel make up only about 12% of its body weight, as compared to about 20% for the strongest flying falcons such as the peregrine. The wings are moderately long, fairly narrow, and taper to a point. Their less muscular body type is adapted to energy-conserving ambush hunting, rather than spending large amounts of energy-consuming time on the wing and getting into long tail-chases of bird prey. For their size, they have strong talons and beaks, and can swiftly dispatch prey. Their lean build and energy-conserving strategy allow a lower daily food intake than if they were more strongly muscled, yet with enough strength to commonly take bird prey as large as themselves, and occasionally larger. The success of this body style and hunting strategy is reflected in the high success of the species in densely populating a large range throughout the Americas. The flight of the American kestrel is not so dramatic and swift as more muscular falcons such as merlins and peregrines, but their efficient adaptation to a broader diet of more available smaller prey, and need for less food per day, has resulted in there being many more of them. In contrast to many other raptor species, the sexes differ more in plumage than in size. Males have blue-grey
wing A wing is a type of fin that produces both Lift (force), lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and a planform (aeronautics), planform. Wing efficiency is expressed as lift-to-d ...
s with black spots and white undersides with black barring. The back is
rufous Rufous () is a color that may be described as reddish-brown or brownish- red, as of rust or oxidised iron. The first recorded use of ''rufous'' as a color name in English was in 1782. However, the color is also recorded earlier in 1527 as a d ...
, with barring on the lower half. The belly and flanks are white with black spotting. The tail is also rufous, with a white or rufous tip and a black subterminal band. The back and wings of the female American kestrel are rufous with dark brown barring. The undersides of the females are creamy to buff with heavy brown streaking. The tail is noticeably different from the male's, being rufous in color with numerous narrow dark black bars. Juveniles exhibit coloration patterns similar to the adults'. In both sexes, the head is white with a bluish-grey top. There are also two narrow, vertical black facial markings on each side of the head, while other falcons have one. Two black spots (ocelli) can be found on each side of the white or orangish nape. The function of these spots is debated, but the most commonly accepted theory is that they act as "false eyes", and help to protect the bird from potential attackers.


Vocalizations

The American kestrel has three basic vocalizations – the "klee" or "killy", the "whine", and the "chitter". The "klee" is usually delivered as a rapid series – ''klee, klee, klee, klee'' when the kestrel is upset or excited. This call is used in a wide variety of situations and is heard from both sexes, but the larger females typically have lower-pitched voices than the males. The "whine" call is primarily associated with feeding but is also uttered during
copulation Sexual intercourse (also coitus or copulation) is a sexual activity typically involving the insertion of the erect male penis inside the female vagina and followed by thrusting motions for sexual pleasure, reproduction, or both.Sexual inte ...
. The "chitter" is used in activities that involve interaction between male and female birds, including
courtship feeding Formally, a nuptial gift is a material presentation to a recipient by a donor during or in relation to sexual intercourse that is not simply gametes in order to improve the reproductive fitness of the donor. Often, such a gift will improve the fit ...
, copulation, and the feeding of nestlings. Nestlings can produce calls similar to those of adults at 16 days old. File:Male American Kestrel.jpg, Male upperparts pattern File:American kestrel (Falco sparverius).jpg, ''F. s. dominicensis'',
Jamaica Jamaica is an island country in the Caribbean Sea and the West Indies. At , it is the third-largest island—after Cuba and Hispaniola—of the Greater Antilles and the Caribbean. Jamaica lies about south of Cuba, west of Hispaniola (the is ...
File:American kestrel (Falco sparverius sparveroides) male red morph.JPG, ''F. s. sparveroides''
male red morph,
Cuba Cuba, officially the Republic of Cuba, is an island country, comprising the island of Cuba (largest island), Isla de la Juventud, and List of islands of Cuba, 4,195 islands, islets and cays surrounding the main island. It is located where the ...
File:American kestrel (Falco sparverius sparveroides) female white morph.JPG, ''F. s. sparveroides''
female white morph,
Cuba Cuba, officially the Republic of Cuba, is an island country, comprising the island of Cuba (largest island), Isla de la Juventud, and List of islands of Cuba, 4,195 islands, islets and cays surrounding the main island. It is located where the ...
File:American kestrel-Midwest.JPG, Perched in central
Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...
File:American kestrel (Falco sparverius) in flight Cayo.jpg, female ''F. s. tropicalis'' in Belize


Ecology and behavior

American kestrels are found in a wide variety of habitats, including
grassland A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...
s,
meadow A meadow ( ) is an open habitat or field, vegetated by grasses, herbs, and other non- woody plants. Trees or shrubs may sparsely populate meadows, as long as they maintain an open character. Meadows can occur naturally under favourable con ...
s,
desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...
s and other open to semi-open regions. They can also be found in both urban and suburban areas. A kestrel's habitat must include perches, open space for hunting, and cavities for nesting (whether natural or man-made). The American kestrel is able to live in very diverse conditions, ranging from above the Arctic Circle, to the tropics of Central America, to elevations of over in the
Andes Mountains The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long and wide (widest between 18°S ...
. The bird is distributed from northern Canada and Alaska to the southernmost tip of South America,
Tierra del Fuego Tierra del Fuego (, ; Spanish for "Land of Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South America, South American mainland, across the Strait of Magellan. The archipelago consists of the main is ...
. It is the only kestrel found in the Americas, though as mentioned above this classification is genetically inaccurate. It has occurred as a vagrant in the UK, Denmark, Malta and the
Azores The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...
. File:American Kestrel on the hunt.jpg, Female about to pounce File:20210506-DSC 3800.jpg, alt=Male showing female a nest box and offering mouse – Maine, Male showing female a nest box and offering mouse – Maine File:20200704-DSC 1454.jpg, alt=Female feeding nestling – Maine, Female feeding nestling – Maine File:20200707-DSC 1815.jpg, alt=Just fledged male, Just fledged male – Maine American kestrels in Canada and the northern United States typically migrate south in the winter, some of them converging with resident kestrels of smaller size in Mexico, sometimes going as far as Central America and the Caribbean. Birds that breed south of about 35° north latitude are usually year-round residents. Migration also depends on local weather conditions. American Kestrels breeding at lower latitudes – below 48ºN to be precise – arrive earlier after warmer springs, whereas birds from higher latitudes return to their breeding grounds at the same time each year. These patterns suggest that short-distance migrants are better able to cope with climate change. Wintering kestrels' choice of habitat varies by sex. Females are found in open areas more often than males during the non-breeding season. A common explanation for this behavior is that the larger females who are bigger than the males arrive at the preferred habitat first and exclude males from their territory. The American kestrel is not long-lived, with a lifespan of <5 years for wild birds. The oldest
band Band or BAND may refer to: Places *Bánd, a village in Hungary * Band, Iran, a village in Urmia County, West Azerbaijan Province, Iran * Band, Mureș, a commune in Romania * Band-e Majid Khan, a village in Bukan County, West Azerbaijan Province, ...
ed wild bird was 11 years and 7 months, while captive kestrels can live up to 14–17 years. In a study, humans accounted for 43.2% of 1,355 reported deaths, which included direct killing and roadkills, while predation (including by larger birds of prey) accounted for 2.8%. This statistic is likely biased, however, as reported deaths are usually found near or in areas populated by humans.


Feeding

American kestrels feed largely on small animals such as
grasshopper Grasshoppers are a group of insects belonging to the suborder Caelifera. They are amongst what are possibly the most ancient living groups of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago. Grassh ...
s,
cricket Cricket is a Bat-and-ball games, bat-and-ball game played between two Sports team, teams of eleven players on a cricket field, field, at the centre of which is a cricket pitch, pitch with a wicket at each end, each comprising two Bail (cr ...
s,
butterflies Butterflies are winged insects from the lepidopteran superfamily Papilionoidea, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The oldest butterfly fossi ...
,
moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...
s,
dragonflies A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of dragonflies are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threate ...
,
beetle Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...
s,
lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...
s,
mice A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
,
vole Voles are small rodents that are relatives of lemmings and hamsters, but with a stouter body; a longer, hairy tail; a slightly rounder head; smaller eyes and ears; and differently formed molars (high-crowned with angular cusps instead of lo ...
s,
shrew Shrews ( family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to dif ...
s,
frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...
s, and small birds. The kestrel has also been reported to have killed
scorpion Scorpions are predatory arachnids of the Order (biology), order Scorpiones. They have eight legs and are easily recognized by a pair of Chela (organ), grasping pincers and a narrow, segmented tail, often carried in a characteristic forward cur ...
s,
snake Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have s ...
s,
bat Bats are flying mammals of the order Chiroptera (). With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most birds, flying with their very long spread-out ...
s, and
squirrel Squirrels are members of the family Sciuridae (), a family that includes small or medium-sized rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrel ...
s. The kestrel is able to maintain high population densities, at least in part because of the broad scope of its diet. The American kestrel's primary mode of hunting is by perching and waiting for prey to come near. The bird is characteristically seen along roadsides or fields perched on objects such as trees,
overhead power line An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy along large distances. It consists of one or more conductors (commonly multiples of three) suspended by towers or poles. ...
s, or fence posts. It also hunts by kiting, hovering in the air with rapid wing beats and scanning the ground for prey. Other hunting techniques include low flight over fields, or chasing insects and birds in the air. Prey is most often caught on the ground, though occasionally they take birds in flight. Before striking, the kestrel characteristically bobs its head and tail, then makes a direct flight toward the prey to grab it in its
talons A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or tars ...
. Much like the
red-tailed hawk The red-tailed hawk (''Buteo jamaicensis'') is a bird of prey that breeds throughout most of North America, from the interior of Alaska and northern Canada to as far south as Panama and the West Indies. It is one of the most common members of ...
, American kestrels conserve energy in a hunt and pick their attacks with care as to position and odds of success. During the breeding season, the bird will carry large prey back to its mate or young. One study found that an American kestrel pair "foraged in ways that minimized the costs of energy acquisition in its particular situation". For example, if the success rate for catching prey decreases significantly in a particular area, the bird will move to a different area.


Reproduction

American kestrels are sexually mature by their first spring. In migratory populations, the males arrive at the breeding ground before females, then the female selects a mate. Pair bonds are strong, often permanent. Pairs usually use previous nesting sites in consecutive years. This gives birds an advantage over younger or invading individuals, as they would already be familiar with the hunting grounds, neighbors, predators, and other features of the site. Males perform elaborate dive displays to advertise their territory and attract a mate. These displays consist of several climbs and dives, with three or four "klee" calls at their peaks. Females are promiscuous for about one to two weeks after their arrival at the nesting site. This is thought to stimulate
ovulation Ovulation is an important part of the menstrual cycle in female vertebrates where the egg cells are released from the ovaries as part of the ovarian cycle. In female humans ovulation typically occurs near the midpoint in the menstrual cycle and ...
. Food transfers from the male to the female occur from about four to five weeks prior to egg laying to one to two weeks after. American kestrels are cavity nesters, but they are able to adapt to a wide variety of nesting situations. They generally prefer natural cavities (such as in trees) with closed tops and tight-fitting entrances that provide for maximum protection of the eggs and young. Kestrels occasionally nest in holes created by large
woodpecker Woodpeckers are part of the bird family (biology), family Picidae, which also includes the piculets, wrynecks and sapsuckers. Members of this family are found worldwide, except for Australia, New Guinea, New Zealand, Madagascar and the extreme ...
s, or use the abandoned nests of other birds, such as
red-tailed hawk The red-tailed hawk (''Buteo jamaicensis'') is a bird of prey that breeds throughout most of North America, from the interior of Alaska and northern Canada to as far south as Panama and the West Indies. It is one of the most common members of ...
s,
merlin The Multi-Element Radio Linked Interferometer Network (MERLIN) is an interferometer array of radio telescopes spread across England. The array is run from Jodrell Bank Observatory in Cheshire by the University of Manchester on behalf of UK Re ...
s, and
crows The Common Remotely Operated Weapon Station (CROWS) is a series of remote weapon stations used by the US military on its armored vehicles and ships. It allows weapon operators to engage targets without leaving the protection of their vehicle. ...
. They have been recorded nesting on cliff ledges and building tops, as well as in abandoned cavities in
cactus A cactus (: cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae (), a family of the order Caryophyllales comprising about 127 genera with some 1,750 known species. The word ''cactus'' derives, through Latin, ...
es. American kestrels also commonly utilize nesting boxes. Three to seven eggs (typically four or five) are laid approximately 24–72 hours apart. (Two supernormal clutches of eight eggs and one of nine have been documented. One egg in one of the eight-egg clutches hatched as did one egg in the nine-egg clutch.) The average egg size is , 10% larger than average for birds of its body size. The eggs are white to cream in color with brown or grey splotching. Incubation usually lasts 30 days and is mainly the responsibility of the female, although the male incubates 15–20% of the time. Eggs that are lost are typically replaced in 11–12 days. Hatching takes place over three to four days. Hatchlings are
altricial Precocial species in birds and mammals are those in which the young are relatively mature and mobile from the moment of birth or hatching. They are normally nidifugous, meaning that they leave the nest shortly after birth or hatching. Altricial ...
, and are only able to sit up after five days. They grow rapidly, reaching an adult weight after 16–17 days. After 28–31 days, their wings have developed and they are able to leave the nest. The young adult kestrels may breed from a year old, and the species has approximately a three to five-year life expectancy in the wild. In ecological terms, the reproductive pattern of the American kestrel leans towards a small bird "''r'' selection" strategy. In ''r''/''K'' selection theory, selective pressures are hypothesized to drive
evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...
in one of two generalized directions: ''r'' or ''K'' selection. ''R''-selected species are those that place an emphasis on a high growth rate, typically exploiting less-crowded
ecological niche In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of Resource (biology), resources an ...
s, and produce many
offspring In biology, offspring are the young creation of living organisms, produced either by sexual reproduction, sexual or asexual reproduction. Collective offspring may be known as a brood or progeny. This can refer to a set of simultaneous offspring ...
, each of which has a relatively low probability of surviving to adulthood (i.e., high ''r'', low ''K''). By contrast, ''K''-selected species display traits associated with living at densities close to
carrying capacity The carrying capacity of an ecosystem is the maximum population size of a biological species that can be sustained by that specific environment, given the food, habitat, water, and other resources available. The carrying capacity is defined as the ...
, and typically are strong competitors in such crowded niches that
invest Investment is traditionally defined as the "commitment of resources into something expected to gain value over time". If an investment involves money, then it can be defined as a "commitment of money to receive more money later". From a broade ...
more heavily in fewer offspring, each of which has a relatively high probability of surviving to adulthood (i.e., low ''r'', high ''K''). Between these two extremes, the American kestrel is one of the few raptor species that lean towards being ''r''-selected. They are able to breed at one year old, have few non-breeding adults in the population, and have larger broods. Their population growth rate is high relative to larger raptors, which typically lean towards being ''K''-selected. This said, older American kestrel pairs generally have larger brood sizes and produce more viable offspring than younger conspecifics.


Stress physiology


Weather

American kestrels are often useful in scientific studies on animal physiology, and are typically captured using the
bal-chatri Bal-chatri () are traps designed to catch birds of prey (raptors). The trap essentially consists of a cage baited inside with a conspicuously visible live rodent or small bird, with a series of monofilament nooses attached to the surface to snar ...
method or raised in nest boxes for experiments. Kestrel metabolic rate has been found to increase in response to rainfall, and at ambient temperatures below about 25 °C. Kestrel metabolic responses to weather and temperature do not vary, however, with sex. Kestrels will increase their oxygen consumption, and therefore their metabolic rate in cold and wet conditions to counteract heat loss.


Environmental disturbance

American kestrels' response to environmental stress is measured as blood concentration of corticosterone (CORT), a hormone produced by the hypothalamic-pituitary-adrenal (HPA) axis that releases stored energy for essential body functions. Extended periods of elevated blood CORT levels may direct metabolic energy away from growth and reproduction. Thus, high levels of traffic disturbance and human development surrounding American kestrel nests are found to increase stress hormones leading to reproductive failure. Among successful nests, however, nestlings do not typically experience a higher stress response to environmental human disturbance, suggesting that they can tolerate a considerable degree of human activity near the nest.


Environmental contaminants

Since American kestrels are carnivores, toxic chemical runoff ingested by their prey can concentrate at high levels in their blood. Wild kestrels are subject to
immunomodulation Immunomodulation is modulation (regulatory adjustment) of the immune system. It has natural and human-induced forms, and thus the word can refer to the following: * Homeostasis in the immune system, whereby the system self-regulates to adjust immun ...
, or an altered immune response, to
polybrominated diphenyl ethers Polybrominated diphenyl ethers or PBDEs, are a class of organobromine compounds that are used as flame retardants. Like other brominated flame retardants, PBDEs have been used in a wide array of products, including building materials, electronic ...
(PBDEs), a group of industrial flame retardants that may leach from factories into the environment. When PBDEs accumulate in body tissues of kestrels, the T-cell mediated immune response decreases in efficiency. As a result, kestrels that ingest PBDEs may not respond sufficiently to viruses or other invading microorganisms. In addition, certain PBDEs may suppress the growth and development of the spleen and bursa in American kestrels. While PBDEs can affect immune response and suppress growth of certain organs, they can also affect the thyroid system of American Kestrels. Exposure to PBDEs ''in vivo'' can alter the thyroid system and retinol concentrations in kestrels. This leads to oxidative stress, lipid peroxidation, and changes in glutathione metabolism. These systems are important in early development, growth, regulation of metabolism, thermoregulation, and reproduction. Oxidative stress is also known to contribute to cancers and neurological diseases. Exposure to
polychlorinated biphenyl Polychlorinated biphenyls (PCBs) are organochlorine compounds with the formula Carbon, C12Hydrogen, H10−''x''Chloride, Cl''x''; they were once widely used in the manufacture of carbonless copy paper, as heat transfer fluids, and as dielectri ...
s (PCBs) might also affect American Kestrel reproduction. It was found that PCBs affect the function of carotenoids in kestrels. This led to changes in coloration, especially during breeding season for adults. PCB-exposed males where duller and contributed less to egg incubation than unexposed males. PCB-exposed females kept their color longer than they should have. Normally, loss in color is associated with carotenoids being directed to ovaries to help in egg development. PCB-exposed females retained their colors longer, suggesting the PCBs made them less prepared for reproduction. The same females also had significant delays in egg laying. Offspring also showed higher incidence of developmental problems and decreased reproductive success. PCBs have also been found to affect eye color in American Kestrels. Eye color in kestrels is known to vary with age and sex, however, when exposed to PCBs, color patterns were suppressed regardless of age and sex. While it is unknown what role eye color plays in visual acuity, this may be of greater concern to birds like kestrels who rely heavily on vision for hunting. PDBEs were linked to changes in breeding behavior in kestrels as well. Different levels of PDBE exposure were linked to different changes in behavior as well. Overall, PDBE exposure led to changes in behaviors that strengthen the bond between a breeding pair. Such behaviors include frequent copulation, food transfers, male posturing, nest box inspection, and specific mating calls (7). High exposure levels led to increases in some behaviors and decreases in some, whereas low exposure caused decreases in almost all behaviors observed. PDBE exposure also altered the timing of these behaviors, often delaying them by several days when compared to the control group. American Kestrels have also been used extensively in toxicology research. Fenthion is a common pesticide that is used to kill insects such as flies and gnats. It was also found that kestrels are highly susceptible to secondary fenthion poisoning. When 14 kestrels were presented with live sparrows who had come into contact with a fenthion solution, all 14 died within 3 days after consuming the sparrows. Diphacinone is another common pesticide that is often used to kill rodents and is thought to be related to secondary poisoning in birds of prey. When kestrels were orally dosed with diphacinone, blood clotting rates significantly decreases. Kestrels were also found to be 20 to 30 times more sensitive to secondary poisoning from diphacinone than other birds like Northern bobwhite and mallard ducks. American kestrels can also be significantly influenced by air contaminants. When exposed to common gaseous pollutants such as benzene, toluene, nitrogen dioxide, and
sulfur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...
, significant changes to the thyroid systems were observed. Higher levels of thyroid activity indicate that exposure to these gases leads to a loss of inhibition of thyroid glands in kestrels. However, there were no changes to immune function or food consumption.


Status and conservation

The American kestrel is likely the most abundant falcon in North America, although its total population is difficult to quantify, as local populations can change quickly due to resource availability. Count data from the USGS
Breeding Bird Survey A breeding bird survey monitors the status and trends of bird populations. Data from the survey are an important source for the range maps found in field guides. The North American Breeding Bird Survey is a joint project of the United States Geo ...
(BBS) indicate that the North American breeding population is experiencing long-term and gradual but sustained declines, with some regions, such as New England and coastal California, exhibiting more rapid declines. Count data from raptor migration corridors also indicate regional population declines and largely corroborate BBS data. The North American population has been estimated at 1.2 million pairs, with the Central and South American populations being as large. A smaller estimate is 236,000 birds wintering in North America. A population increase occurred in the 18th and 19th centuries, probably due to deforestation for agriculture. The resulting pastures provided an ideal habitat for kestrels. The southeastern U.S. subspecies (''Falco sparverius paulus'') has declined 82% since 1940 due to a decrease in nest site availability. This decline is a result of
longleaf pine The longleaf pine (''Pinus palustris'') is a pine species native to the Southeastern United States, found along the coastal plain from East Texas to southern Virginia, extending into northern and central Florida. In this area it is also known as ...
s being cleared for agricultural fields. Despite this, the American kestrel is classed as
least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
on the
IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...
.
The Peregrine Fund The Peregrine Fund (named after the bird of prey of the same name the peregrine falcon) is a non-profit organization founded in 1970 that conserves threatened and endangered birds of prey worldwide. The successful recovery of the peregrine falcon ...
, a leading non-profit organization advancing research and conservation of birds of prey worldwide, launched the American Kestrel Partnership in 2012. The American Kestrel Partnership developed and maintains a web-based network for citizen and professional scientists to enter, manage, and consolidate data from kestrel nest box monitoring programs in the Western Hemisphere. The database is being used by researchers to model and understand relationships between kestrel nesting parameters (e.g., phenology, occupancy, survival, productivity, and nestling weight and exposure to environmental toxins) and environmental factors, such as land use, landscape composition and configuration, climate conditions (e.g., drought), and point sources of environmental toxins. Each breeding season, the American Kestrel Partnership features a live-streaming video feed from the nest box located at The Peregrine Fund's campus in Boise, Idaho.


Use in falconry

One important use of American kestrels is in
falconry Falconry is the hunting of wild animals in their natural state and habitat by means of a trained bird of prey. Small animals are hunted; squirrels and rabbits often fall prey to these birds. Two traditional terms are used to describe a person ...
. It is often considered a beginner's bird, though the careful weight control needed to maintain the kestrel's desire to aggressively hunt takes skill. Falconers experienced in extracting the best performance the species is capable of, report they are highly reliable on the normal game of sparrows and starlings. More aggressive individuals are sometimes capable of capturing prey up to approximately twice their own body weight, allowing the occasional capture of true game birds such as quail and dove. However, most falconers interested in the reliable taking of such game do prefer larger falcons or hawks. The advantage the American kestrel offers the experienced falconer is its suitability to simple and urban falconry not requiring large tracts of land or the use of hunting dogs. This form of falconry is sometimes referred to as "micro-falconry" or "micro-hawking". The other small raptor species commonly used in micro-falconry are the
merlin The Multi-Element Radio Linked Interferometer Network (MERLIN) is an interferometer array of radio telescopes spread across England. The array is run from Jodrell Bank Observatory in Cheshire by the University of Manchester on behalf of UK Re ...
, the
sharp-shinned hawk The sharp-shinned hawk (''Accipiter striatus'') or northern sharp-shinned hawk, commonly known as a sharpie, is a small hawk, with males being the smallest hawks in the United States and Canada, but with the species averaging larger than some Neo ...
(the smallest
accipiter ''Accipiter'' () is a genus of birds of prey in the family Accipitridae. Some species are called sparrowhawks, but there are many sparrowhawks in other genera such as '' Tachyspiza''. These birds are slender with short, broad, rounded wings and ...
), and the European kestrel (a true kestrel). Hawking with the American kestrel requires adapting to the strengths and weaknesses of the bird. It is a tiny falcon, and even for its size, it is less muscular than other small falcons such as the athletic and swift
merlin The Multi-Element Radio Linked Interferometer Network (MERLIN) is an interferometer array of radio telescopes spread across England. The array is run from Jodrell Bank Observatory in Cheshire by the University of Manchester on behalf of UK Re ...
. It is more adapted to ambush hunting and short chases than to the longer aerial chases larger falcons often adopt. Used within its limits, it is effective. Experienced falconer Matthew Mullenix, author of the book ''American Kestrels in Modern Falconry'', in an article comparing kestrels to merlins, summed their abilities up as follows: 1. "Kestrels are thin-winged, flat-chested, under-powered and lack acceleration compared to merlins. I say that with much affection for them and with thousands of kestrel kills to prove these are not necessarily damning differences. Comparing a red-tailed hawk to a Harris' or goshawk will conjure equally negative points of fact, yet we all know how good trained red-tails can be!" 2. "The chief variable to choosing between a kestrel and a merlin may be your hawking land. If you live in open country or have access at least to good pasture for cattle, a merlin can excel there. If you plan to hunt mostly in town or suburb, and especially if you plan to hawk from a car, I'd recommend the kestrel. The consideration coming in at close second is your intended quarry. To snipe, dove, quail and open-country sparrows, merlins are best suited. For most blackbirds (Icteridea), either falcon can prove effective. Starlings in close are extremely vulnerable to kestrels, but in the open are best prey for merlins. The same holds true for house sparrows, with this exception: sparrows in thick cover are better quarry for kestrels. This is the slip for which I feel the American kestrel is perfect." 3. "Once committed to an attack, trained kestrels tend to follow through to the end. They will stoop into cover, chase birds on foot, bind to quarry twice their size, and never let go voluntarily. They have small feet, but as written elsewhere, also have the strongest feet for their size. It is a simple fact that American kestrels hold starlings better than merlins, on average, and will gladly tackle larger quarry than will any jack (male merlin)." American kestrels do not train so easily as some larger falcons (particularly the
peregrine falcon The peregrine falcon (''Falco peregrinus''), also known simply as the peregrine, is a Cosmopolitan distribution, cosmopolitan bird of prey (raptor) in the family (biology), family Falconidae renowned for its speed. A large, Corvus (genus), cro ...
) in the art of "waiting on" to perform a diving stoop on flushed prey. However, some individual kestrels do master this skill. Falconers sometimes train them to climb to a stooping position with tidbits on kites or balloons that the kestrels learn to climb after. More common hunting techniques are to "slip" them after spotted game from the fist, or to release them from a vehicle window close to spotted quarry. These techniques are more of a natural fit to the kestrel's ambushing methods in the wild. Falconers using the American kestrel should be alert to protect the falcon from larger predators that may attack the kestrel, particularly if it is distracted on the ground with captured prey. Domestic cats and dogs are the greatest threat to attack the falcon on the ground, but the Cooper's hawk is well known to boldly attack kestrels. This mid-sized American
accipiter ''Accipiter'' () is a genus of birds of prey in the family Accipitridae. Some species are called sparrowhawks, but there are many sparrowhawks in other genera such as '' Tachyspiza''. These birds are slender with short, broad, rounded wings and ...
has sufficient size and strength to carry the kestrel away, though falconers have reported often being successful in recovering the kestrel unharmed by acting quickly to intimidate the larger hawk into releasing the kestrel. American kestrels are bred in captivity for use in falconry and are among the easier falcons to breed. They are also sufficiently common that "passage" birds in their first year are relatively easy to trap. Wild-caught kestrels "tame down" fairly quickly. They will usually be eating from a falconer's hand the day after capture, be training within a week, and be ready to hunt in three to five weeks. A very tame American kestrel will allow itself to be picked up around the body with one hand while accepting tidbits from the other hand. Such tameness is very useful when checking or treating the bird for injury or illness. Migratory raptors native to the United States are protected by the Migratory Bird Treaty Act of 1918, so American kestrels are illegal to possess without a permit (such as a falconry permit) in the United States, Canada, and Mexico.


References


Cited books

* *


External links


American Kestrel Partnership, The Peregrine Fund
Research and conservation activities designed for participants of all ages *
KestrelCams, American Kestrel Partnership, The Peregrine Fund
Live, streaming video of a nesting kestrel pair
Photos, audio and video of American kestrel
from Cornell Lab of Ornithology's Macaulay Library
American Kestrel – ''Falco sparverius''
– USGS Patuxent Bird Identification InfoCenter * {{Authority control Falco (genus), American kestrel Birds of the Americas Birds of the Dominican Republic Birds described in 1758, American kestrel Taxa named by Carl Linnaeus, American kestrel