Wood Thrush
Encyclopedia
The Wood Thrush, Hylocichla mustelina, is a North American passerine
bird
. It is closely related to other thrushes such as the American Robin
and is widely distributed across North America, wintering in Central America
and southern Mexico
. The Wood Thrush is the official bird of the District of Columbia.
The Wood Thrush is a medium-sized thrush
, with brown upper parts with mottled brown and white underparts. The male and female are similar in appearance. The male has one of the most beautiful songs of birds in North America.
The Wood Thrush is an omnivore
, and feeds preferentially on soil invertebrates and larvae, but will also eat fruits. In the summer, it feeds on insects continuously in order to meet daily metabolic needs. It is solitary, but sometimes form mixed-species flocks. The Wood Thrush defends a territory
that ranges in size from 800 to 28000 square meters. The Wood Thrush is monogamous, and its breeding season begins in the spring; about 50 percent of all mated pairs are able to raise two broods, ranging in size from 2 to 4 chicks.
naturalist
Johann Friedrich Gmelin
in 1789. The generic name is a direct translation of its common name, derived from the Greek
words hyle/ύλη "woodland" and cichle/κιχλη "thrush" or "fieldfare
". The specific name comes from the Latin
mustela "weasel". It is closely related to the other typical American thrushes of the genus Catharus
, and is sometimes merged into that genus;. It has been considered close to the long-distance migrant
species of that genus, as opposed to the generally resident nightingale-thrushes, but this appears to be erroneous. The Wood Thrush also appears to be fairly closely related to the large Turdus thrushes, such as the American Robin
.
wrote:
While the female is not known to sing, the male has a unique song that has three parts. The first subsong component is often inaudible unless the listener is close, and consists of two to six short, low-pitched notes such as bup, bup, bup. The middle part is a loud phrase often written ee-oh-lay, and the third part is a ventriloquial, trill-like phrase of non-harmonic pairs of notes given rapidly and simultaneously.
The male is able to sing two notes at once, which gives its song an ethereal, flute-like quality. Each individual bird has its own repertoire based on combinations of variations of the three parts. Songs are often repeated in order. The bup, bup, bup phrase is also sometimes used as a call, which is louder and at a greater frequency when the bird is agitated. The Wood Thrush also use a tut, tut to signal agitation. The nocturnal flight call is an emphatic buzzing heeh.
, Ontario
and Nova Scotia
in southern Canada
to northern Florida
and from the Atlantic
coast to the Missouri River
and the eastern Great Plains
. It migrates
to southern Mexico
through to Panama
in Central America
in the winter, mostly in the lowlands along the Atlantic
and Pacific
coasts. It generally arrives on the U.S. Gulf Coast during the first week of April. Fall migration usually begins in mid-August and continues through mid-September. Migration takes place at night, allowing them to find their direction from the star
s and orient themselves by detecting the Earth's magnetic field
.
The Wood Thrush prefers deciduous
and mixed forests for breeding. It prefers late-successional, upland mesic forests with a moderately-dense shrub layer. Robert I. Bertin (1977) found that this thrush favors areas with running water, moist ground, and high understorey cover. The breeding habitat generally includes trees taller than 16 m (50 ft), a fairly open forest floor, moist soil, and leaf litter, with substrate moisture more important than either canopy cover or access to running water. The Wood Thrush can breed in habitat patches as small as 0.4 hectares (1 acre), but it runs the risk of higher predation and nest parasitism
. The Wood Thrush's breeding range has expanded northward, displacing the Veery
and Hermit Thrush
in some locations. In recent times, as a result of fragmentation of forests, it has been increasingly exposed to
nest parasitism
by Brown-headed Cowbird
s, as well as loss of habitat
in the winter range.
was the first large-scale analysis that linked acid rain
to this thrush's decline. Continued destruction of primary forest in Central America eliminated preferred Wood Thrush wintering habitats, likely forcing the birds to choose secondary habitats where mortality rates are higher. In spite of this, the Wood Thrush is still considered to be of least concern
.
, on the Isles of Scilly
, England
in October 1987.
This species has also been observed displaying a behavior known as anting. Anting occurs when a bird picks up a single ant
or group of ants and rubs them on its feathers. The purpose of this behavior is unknown, but it is thought that the birds may be able to acquire defensive secretions from the ants possibly used for some medicinal purposes, or that it simply supplements the birds' own preen oil.
s, snail
s, and small salamander
s. The young are fed insects and some fruit. After breeding and before migration, the Wood Thrush will switch from insects to fruits with high lipid levels. In the summer, low fruit consumption and lipid reserves require the bird to feed on insects continuously in order to meet its metabolic needs.
The Wood Thrush forages mainly on the forest floor, flipping leaves over with their bills to reveal insects. It can be observed hopping around in leaf litter and on semi-bare ground under the forest canopy. Fruits are swallowed whole.
s, raccoon
s, Blue Jay
s, American Crow
s, black rat snakes, Brown-headed Cowbird
s, Common Grackle
s, southern flying squirrel
s, gray squirrels
, least weasel
s, white-footed mice
, domestic cat
s, Great Horned Owl
s, and Sharp-shinned Hawk
s. Adults are primarily taken by hawk
s and owl
s.
Some male Wood Thrushes arrive at the breeding grounds several days before the earliest females while other males arrive at the same time as the females, establishing territories ranging in size from 0.08 to 0.8 hectares (one-fifth of an acre to two acres). The female typically leads silent circular flights 1-1.8 m (3–6 ft) from the ground, with the male chasing. Six or more flights generally take place in succession. The pairs will perch together and feed each other in between flights. The male begins to sing at dawn and dusk a few days after arriving at breeding grounds. Early in the breeding season, the male sings from high perches in the tallest trees, but as the season progresses, it sings somewhat shorter and less elaborate songs from lower perches. Each day's singing begins and is most intense just before sunrise. The male may sing throughout the day but especially at dusk. The song season is usually over by the end of July.
Typically, the female chooses the nest site and builds the nest. However, there has been some indication that the male is able to influence the selection of the nest site by perching nearby and singing. Usually, though, the female chooses whether or not to accept or reject the nest site suggested by the male. The nest is usually sited in a dense patch of vegetation in a tree or shrub that provides concealment and shade. It is usually made of dead grasses, stems, and leaves, and lined with mud, and placed in a fork at a horizontal branch. The nest
is not reused. Usually, two broods are attempted, although three to four separate nests may be built before a pair succeeds. Two to four pale blue eggs are laid at the rate of one per day. The eggs
are incubated by the female only for 11 to 14 days, with the average being 13 days. Like all passerines, the chicks are altricial
at hatching, mostly naked with closed eyes. The female broods the chicks during the first four days after hatching. Both parents feed the nestlings and remove fecal sacs from the nest. The chicks fledge
12–15 days after hatching, but the parents continue to feed them until they become independent and leave the parents' territory at 21–31 days old.
The young Wood Thrush is able to begin breeding the next summer. Most females lay their first eggs in mid-May, but older females may begin laying sooner. Pairs usually attempt to rear a second brood no later than late July, with the last of the young fledging around mid-August. About half of all Wood Thrush pairs successfully raise two broods.
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
. It is closely related to other thrushes such as the 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...
and is widely distributed across North America, wintering in 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...
and southern Mexico
Mexico
The 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...
. The Wood Thrush is the official bird of the District of Columbia.
The Wood Thrush is a medium-sized thrush
Thrush (bird)
The thrushes, family Turdidae, are a group of passerine birds that occur worldwide.-Characteristics:Thrushes are plump, soft-plumaged, small to medium-sized birds, inhabiting wooded areas, and often feed on the ground or eat small fruit. The smallest thrush may be the Forest Rock-thrush, at and...
, with brown upper parts with mottled brown and white underparts. The male and female are similar in appearance. The male has one of the most beautiful songs of birds in North America.
The Wood Thrush is an omnivore
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...
, and feeds preferentially on soil invertebrates and larvae, but will also eat fruits. In the summer, it feeds on insects continuously in order to meet daily metabolic needs. It is solitary, but sometimes form mixed-species flocks. The Wood Thrush defends a territory
Territory (animal)
In ethology the term territory refers to any sociographical area that an animal of a particular species consistently defends against conspecifics...
that ranges in size from 800 to 28000 square meters. The Wood Thrush is monogamous, and its breeding season begins in the spring; about 50 percent of all mated pairs are able to raise two broods, ranging in size from 2 to 4 chicks.
Taxonomy
The only member of the genus Hylocichla, the Wood Thrush was described by GermanGermany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
naturalist
Natural history
Natural history is the scientific research of plants or animals, leaning more towards observational rather than experimental methods of study, and encompasses more research published in magazines than in academic journals. Grouped among the natural sciences, natural history is the systematic study...
Johann Friedrich Gmelin
Johann Friedrich Gmelin
Johann Friedrich Gmelin was a German naturalist, botanist, entomologist, herpetologist and malacologist.- Education :Johann Friedrich Gmelin was born as the eldest son of Philipp Friedrich Gmelin in 1748 in Tübingen...
in 1789. The generic name is a direct translation of its common name, derived from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
words hyle/ύλη "woodland" and cichle/κιχλη "thrush" or "fieldfare
Fieldfare
The Fieldfare is a member of the thrush family Turdidae. It breeds in woodland and scrub in northern Europe and Asia. It is strongly migratory, with many northern birds moving south during the winter. It is a very rare breeder in Great Britain and Ireland, but winters in large numbers in these...
". The specific name comes from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
mustela "weasel". It is closely related to the other typical American thrushes of the genus Catharus
Catharus
Catharus is a genus of birds in the thrush family Turdidae. It contains the small, mostly insectivorous or omnivorous migrant thrushes of North America and the nightingale-thrushes of Central and South America...
, and is sometimes merged into that genus;. It has been considered close to the long-distance migrant
Bird migration
Bird 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...
species of that genus, as opposed to the generally resident nightingale-thrushes, but this appears to be erroneous. The Wood Thrush also appears to be fairly closely related to the large Turdus thrushes, such as the 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...
.
Description
The adult Wood Thrush is 19–21 cm (7½-8¼ in) long, and weighs 40-50 g, with a wingspan of 30–40 cm (12–16 in). The longest known lifespan for a Wood Thrush in the wild is 8 years, 11 months. The crown, nape, and upper back are cinnamon-brown, while the back wings, and tail are a slightly duller brown. The breast and belly are white with large dark brown spots on the breast, sides, and flanks. It has white eye rings and pink legs. Other brownish thrushes have finer spotting on the breast. The juvenile looks similar to adults, but has additional spots on the back, neck, and wing coverts. The male and female are similar in size and plumage.Vocalizations
The Wood Thrush has been reported to have one of the most beautiful songs of North American birds. American naturalist Henry David ThoreauHenry David Thoreau
Henry David Thoreau was an American author, poet, philosopher, abolitionist, naturalist, tax resister, development critic, surveyor, historian, and leading transcendentalist...
wrote:
Whenever a man hears it he is young, and Nature is in her spring; wherever he hears it, it is a new world and a free country, and the gates of Heaven are not shut against him.
While the female is not known to sing, the male has a unique song that has three parts. The first subsong component is often inaudible unless the listener is close, and consists of two to six short, low-pitched notes such as bup, bup, bup. The middle part is a loud phrase often written ee-oh-lay, and the third part is a ventriloquial, trill-like phrase of non-harmonic pairs of notes given rapidly and simultaneously.
The male is able to sing two notes at once, which gives its song an ethereal, flute-like quality. Each individual bird has its own repertoire based on combinations of variations of the three parts. Songs are often repeated in order. The bup, bup, bup phrase is also sometimes used as a call, which is louder and at a greater frequency when the bird is agitated. The Wood Thrush also use a tut, tut to signal agitation. The nocturnal flight call is an emphatic buzzing heeh.
Distribution and habitat
The Wood Thrush's breeding range extends from ManitobaManitoba
Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...
, Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
and Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
in southern 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...
to northern Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
and from the Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
coast to the Missouri River
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...
and the eastern Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
. It migrates
Bird migration
Bird 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...
to southern Mexico
Mexico
The 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...
through to Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
in 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...
in the winter, mostly in the lowlands along the Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
and Pacific
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
coasts. It generally arrives on the U.S. Gulf Coast during the first week of April. Fall migration usually begins in mid-August and continues through mid-September. Migration takes place at night, allowing them to find their direction from the star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s and orient themselves by detecting the Earth's magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
.
The Wood Thrush prefers deciduous
Deciduous
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...
and mixed forests for breeding. It prefers late-successional, upland mesic forests with a moderately-dense shrub layer. Robert I. Bertin (1977) found that this thrush favors areas with running water, moist ground, and high understorey cover. The breeding habitat generally includes trees taller than 16 m (50 ft), a fairly open forest floor, moist soil, and leaf litter, with substrate moisture more important than either canopy cover or access to running water. The Wood Thrush can breed in habitat patches as small as 0.4 hectares (1 acre), but it runs the risk of higher predation and nest parasitism
Edge effect
The edge effect in ecology is the effect of the juxtaposition or placing side by side of contrasting environments on an ecosystem.This term is commonly used in conjunction with the boundary between natural habitats, especially forests, and disturbed or developed land. Edge effects are especially...
. The Wood Thrush's breeding range has expanded northward, displacing the Veery
Veery
The Veery, Catharus fuscescens, is a small thrush species. It is occasionally called Willow Thrush or Wilson's Thrush. It is a member of a close-knit group of migrant Catharus species, which also includes the cryptotaxa Grey-cheeked Thrush and Bicknell's Thrush The Veery, Catharus fuscescens, is a...
and Hermit Thrush
Hermit Thrush
The Hermit Thrush is a medium-sized North American thrush. It is not very closely related to the other North American migrant species of Catharus, but rather to the Mexican Russet Nightingale-thrush.-Description:...
in some locations. In recent times, as a result of fragmentation of forests, it has been increasingly exposed to
nest parasitism
Edge effect
The edge effect in ecology is the effect of the juxtaposition or placing side by side of contrasting environments on an ecosystem.This term is commonly used in conjunction with the boundary between natural habitats, especially forests, and disturbed or developed land. Edge effects are especially...
by Brown-headed Cowbird
Brown-headed Cowbird
The Brown-headed Cowbird is a small brood parasitic icterid of temperate to subtropical North America. They are permanent residents in the southern parts of their range; northern birds migrate to the southern United States and Mexico in winter, returning to their summer habitat around March or...
s, as well as loss of habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
in the winter range.
Conservation status
The Wood Thrush has become a symbol of the decline of Neotropical songbirds of eastern North America, having declined 43 percent since 1966. Along with many other species, this thrush faces threats both to is North American breeding grounds and Central American wintering grounds. Forest fragmentation in North American forests has resulted in both increased nest predation and increased cowbird parasitism, significantly reducing their reproductive success. A study by the Cornell Laboratory of OrnithologyCornell Laboratory of Ornithology
The Cornell Lab of Ornithology is a member-supported unit of Cornell University in Ithaca, New York which studies birds and other wildlife. It is housed in the Imogene Powers Johnson Center for Birds and Biodiversity in Sapsucker Woods Sanctuary...
was the first large-scale analysis that linked acid rain
Acid rain
Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions . It can have harmful effects on plants, aquatic animals, and infrastructure. Acid rain is caused by emissions of carbon dioxide, sulfur dioxide and nitrogen...
to this thrush's decline. Continued destruction of primary forest in Central America eliminated preferred Wood Thrush wintering habitats, likely forcing the birds to choose secondary habitats where mortality rates are higher. In spite of this, the Wood Thrush is still considered to be of least concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
.
Vagrancy
The Wood Thrush has occurred as a vagrant once in EuropeEurope
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, on the Isles of Scilly
Isles of Scilly
The Isles of Scilly form an archipelago off the southwestern tip of the Cornish peninsula of Great Britain. The islands have had a unitary authority council since 1890, and are separate from the Cornwall unitary authority, but some services are combined with Cornwall and the islands are still part...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
in October 1987.
Behavior
The Wood Thrush is primarily solitary, but occasionally forms mixed-species flocks in the winter. Its breeding territory range from 800 to at least 8000 square meters in size, and are used for nesting, gathering nest materials, and foraging. Some Wood Thrushes also defend a feeding territory in the winter. Territorial interactions are usually settled without physical contact, but in high-intensity encounters or nest defense, physical interactions with the feet or bill have been observed. Defense behaviors in response to nest predators include wing flicks, tail flicks, and raising the crest, sometimes escalating to dives and strikes.This species has also been observed displaying a behavior known as anting. Anting occurs when a bird picks up a single ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
or group of ants and rubs them on its feathers. The purpose of this behavior is unknown, but it is thought that the birds may be able to acquire defensive secretions from the ants possibly used for some medicinal purposes, or that it simply supplements the birds' own preen oil.
Diet
Soil invertebrates and larvae make up most of the Wood Thrush's omnivorous diet, but it will also eat fruits in the late summer, fall, and late winter. It occasionally feeds on arboreal insectInsect
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, snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s, and small salamander
Salamander
Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...
s. The young are fed insects and some fruit. After breeding and before migration, the Wood Thrush will switch from insects to fruits with high lipid levels. In the summer, low fruit consumption and lipid reserves require the bird to feed on insects continuously in order to meet its metabolic needs.
The Wood Thrush forages mainly on the forest floor, flipping leaves over with their bills to reveal insects. It can be observed hopping around in leaf litter and on semi-bare ground under the forest canopy. Fruits are swallowed whole.
Predation
Eggs and chicks are vulnerable to chipmunkChipmunk
Chipmunks are small striped squirrels native to North America and Asia. They are usually classed either as a single genus with three subgenera, or as three genera.-Etymology and taxonomy:...
s, raccoon
Raccoon
Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...
s, Blue Jay
Blue Jay
The Blue Jay is a passerine bird in the family Corvidae, native to North America. It is resident through most of eastern and central United States and southern Canada, although western populations may be migratory. It breeds in both deciduous and coniferous forests, and is common near and in...
s, American Crow
American Crow
The American Crow is a large passerine bird species of the family Corvidae. It is a common bird found throughout much of North America...
s, black rat snakes, Brown-headed Cowbird
Brown-headed Cowbird
The Brown-headed Cowbird is a small brood parasitic icterid of temperate to subtropical North America. They are permanent residents in the southern parts of their range; northern birds migrate to the southern United States and Mexico in winter, returning to their summer habitat around March or...
s, Common Grackle
Common Grackle
The Common Grackle, Quiscalus quiscula, is a large icterid.-Description:The long adult has a long dark bill, pale yellowish eyes and a long tail; its feathers appear black with purple, green or blue iridescence on the head, and primarily bronze shine in the body plumage...
s, southern flying squirrel
Southern Flying Squirrel
The Southern Flying Squirrel is one of two species of the genus Glaucomys, the only flying squirrels found in North America . It is found in deciduous and mixed woods in the eastern half of North America, from southeastern Canada, to Florida, USA...
s, gray squirrels
Eastern Gray Squirrel
The eastern gray squirrel is a tree squirrel in the genus Sciurus native to the eastern and midwestern United States, and to the southerly portions of the eastern provinces of Canada...
, least weasel
Least Weasel
The least weasel is the smallest member of the Mustelidae , native to Eurasia, North America and North Africa, though it has been introduced elsewhere. It is classed as Least Concern by the IUCN, due to its wide distribution and presumably large population...
s, white-footed mice
White-footed mouse
White-footed Mouse is a rodent native to North America. It ranges from Ontario, Quebec, Labrador and the Maritime Provinces to the southwest USA and Mexico. It is also known as the Woodmouse, particularly in Texas.Adults are in length, not counting the tail, which can add another . A young adult...
, domestic cat
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
s, Great Horned Owl
Great Horned Owl
The Great Horned Owl, , also known as the Tiger Owl, is a large owl native to the Americas. It is an adaptable bird with a vast range and is the most widely distributed true owl in the Americas.-Description:...
s, and Sharp-shinned Hawk
Sharp-shinned Hawk
The Sharp-shinned Hawk is a small hawk. In fact, "sharp-shins" or "sharpies" are the smallest to reside in USA and Canada, though some Neotropical species are smaller...
s. Adults are primarily taken by hawk
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,...
s and owl
Owl
Owls are a group of birds that belong to the order Strigiformes, constituting 200 bird of prey species. Most are solitary and nocturnal, with some exceptions . Owls hunt mostly small mammals, insects, and other birds, although a few species specialize in hunting fish...
s.
Reproduction
Wood Thrushes are monogamous. Breeding pairs form in mid-April to early-May, and usually last throughout the breeding season. Most thrushes find a new mate each year, and mate guarding and extra-pair copulations have not been observed in this species.Some male Wood Thrushes arrive at the breeding grounds several days before the earliest females while other males arrive at the same time as the females, establishing territories ranging in size from 0.08 to 0.8 hectares (one-fifth of an acre to two acres). The female typically leads silent circular flights 1-1.8 m (3–6 ft) from the ground, with the male chasing. Six or more flights generally take place in succession. The pairs will perch together and feed each other in between flights. The male begins to sing at dawn and dusk a few days after arriving at breeding grounds. Early in the breeding season, the male sings from high perches in the tallest trees, but as the season progresses, it sings somewhat shorter and less elaborate songs from lower perches. Each day's singing begins and is most intense just before sunrise. The male may sing throughout the day but especially at dusk. The song season is usually over by the end of July.
Typically, the female chooses the nest site and builds the nest. However, there has been some indication that the male is able to influence the selection of the nest site by perching nearby and singing. Usually, though, the female chooses whether or not to accept or reject the nest site suggested by the male. The nest is usually sited in a dense patch of vegetation in a tree or shrub that provides concealment and shade. It is usually made of dead grasses, stems, and leaves, and lined with mud, and placed in a fork at a horizontal branch. The nest
Bird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
is not reused. Usually, two broods are attempted, although three to four separate nests may be built before a pair succeeds. Two to four pale blue eggs are laid at the rate of one per day. The eggs
Bird egg
Bird eggs are laid by females and incubated for a time that varies according to the species; a single young hatches from each egg. Average clutch sizes range from one to about 17...
are incubated by the female only for 11 to 14 days, with the average being 13 days. Like all passerines, the chicks are altricial
Altricial
Altricial, meaning "requiring nourishment", refers to a pattern of growth and development in organisms which are incapable of moving around on their own soon after hatching or being born...
at hatching, mostly naked with closed eyes. The female broods the chicks during the first four days after hatching. Both parents feed the nestlings and remove fecal sacs from the nest. The chicks fledge
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
12–15 days after hatching, but the parents continue to feed them until they become independent and leave the parents' territory at 21–31 days old.
The young Wood Thrush is able to begin breeding the next summer. Most females lay their first eggs in mid-May, but older females may begin laying sooner. Pairs usually attempt to rear a second brood no later than late July, with the last of the young fledging around mid-August. About half of all Wood Thrush pairs successfully raise two broods.
External links
- Wood Thrush - Hylocichla mustelina - USGS Patuxent Bird Identification InfoCenter
- Wood Thrush Information - South Dakota Birds and Birding
- Wood Thrush Species Account - Cornell Lab of Ornithology
- Wood Thrush videos on the Internet Bird Collection
- Bird photograph and song: Wood Thrush - Audio clip
- Is Acid Rain Killing Off Wood Thrushes? - Nationalgeographic.com
- Wood Thrush Bird Sound