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Kirtland's warbler (''Setophaga kirtlandii''), also known in Michigan by the
common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...
jack pine bird, or the jack pine warbler, is a small
songbird A songbird is a bird belonging to the suborder Passeri of the perching birds (Passeriformes). Another name that is sometimes seen as the scientific or vernacular name is Oscines, from Latin ''oscen'', "songbird". The Passeriformes contains 5,00 ...
of the New World warbler
family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
(
Parulidae The New World warblers or wood-warblers are a group of small, often colorful, passerine birds that make up the family Parulidae and are restricted to the New World. The family contains 120 species. They are not closely related to Old World warb ...
). Nearly
extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
just years ago, populations have recovered due to the conservation efforts of the Kirtland's Warbler Conservation Team and its members. The birds require large areas, greater than 160 acres (65 hectares), of dense young
jack pine Jack pine (''Pinus banksiana''), also known as grey pine or scrub pine, is a North American pine. Distribution and habitat Its native range in Canada is east of the Rocky Mountains from the Mackenzie River in the Northwest Territories t ...
for breeding habitat. This habitat was historically created by wildfire, but today is created through the harvest of mature
jack pine Jack pine (''Pinus banksiana''), also known as grey pine or scrub pine, is a North American pine. Distribution and habitat Its native range in Canada is east of the Rocky Mountains from the Mackenzie River in the Northwest Territories t ...
(''Pinus banksiana''), and planting of jack pine seedlings. The population of the
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
spends the spring and summer in its breeding range in the
Great Lakes region The Great Lakes region of Northern America is a binational Canadian– American region centered on the Great Lakes that includes the U.S. states of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin and the Ca ...
of Canada (
Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...
) and the United States (
Wisconsin Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...
and
Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...
, especially in the northeastern Lower Peninsula), and winters in the
West Indies The West Indies is an island subregion of the Americas, surrounded by the Atlantic Ocean, North Atlantic Ocean and the Caribbean Sea, which comprises 13 independent island country, island countries and 19 dependent territory, dependencies in thr ...
.


Taxonomy

This species was first recorded by Europeans relatively late for a bird from eastern
North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
. The first specimen was shot at sea somewhere between the
Abaco Islands The Abaco Islands lie in the north of Bahamas, The Bahamas, about 193 miles (167.7 nautical miles or 310.6 km) east of Miami, Florida, US. The main islands are Great Abaco and Little Abaco, which is just west of Great Abaco's northern tip. T ...
of
The Bahamas The Bahamas, officially the Commonwealth of The Bahamas, is an Archipelagic state, 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 ...
and
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 ...
in mid-October 1841 by the
ornithologist Ornithology, from Ancient Greek ὄρνις (''órnis''), meaning "bird", and -logy from λόγος (''lógos''), meaning "study", is a branch of zoology dedicated to the study of birds. Several aspects of ornithology differ from related discip ...
Samuel Cabot III Samuel Cabot III (September 20, 1815 – April 13, 1885) was an American physician, surgeon, and ornithologist, as well as a member of the wealthy and prominent Cabot family. Early life Samuel Cabot III was born in Boston, Massachusetts on Septem ...
. However, the specimen was unrecognized as a new species in the private collection of Cabot's father, Boston merchant Samuel Cabot Jr., until it made its way to the Museum of the Smithsonian Institution in the 1860s. Ten years later the
holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
, a juvenile male, was shot on Jared Potter Kirtland's farm near
Cleveland, Ohio Cleveland is a city in the U.S. state of Ohio and the county seat of Cuyahoga County, Ohio, Cuyahoga County. Located along the southern shore of Lake Erie, it is situated across the Canada–United States border, Canada–U.S. maritime border ...
, in mid-May 1851. It was used to formally describe the species as ''Sylvicola kirtlandii'' by
Spencer Fullerton Baird Spencer Fullerton Baird (; February 3, 1823 – August 19, 1887) was an American naturalist, ornithologist, ichthyologist, Herpetology, herpetologist, and museum curator. Baird was the first curator to be named at the Smithsonian Institution. He ...
in 1852. Baird first attributed the collection to Charles Pease (Kirtland's son-in-law) in his 1852 description, but by 1858 he had changed his story and was attributing it to Kirtland. In 1858 Baird moved the species, still then only known from his single specimen, to the genus '' Dendroica'', where it remained until the 2010s, when it (and all other ''Dendroica'' warblers) was merged into the genus '' Setophaga''. By 1865 only four individuals were known to have been collected. Baird lists the male specimen from the Cabot collection, the holotype, a first female specimen shot in 1860 near Cleveland and preserved by R. K. Winslow, and a fourth (which Winslow mentioned had also been killed near Cleveland but had not been preserved). Local naturalist Philo Romayne Hoy also mentioned having possibly seen the species once near the village of Racine, Ohio, in the 1850s.


Etymology

Baird decided to name the bird after Jared Potter Kirtland: "a gentleman to whom, more than any one living, we are indebted for a knowledge of the
Natural History Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...
of the
Mississippi Valley The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...
". The generic epithet ''Setophaga'' is from the
genitive case In grammar, the genitive case ( abbreviated ) is the grammatical case that marks a word, usually a noun, as modifying another word, also usually a noun—thus indicating an attributive relationship of one noun to the other noun. A genitive ca ...
of
Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...
σής, transliterated as ''sḗs'', meaning "moth", and ', meaning "eating".


Description

Male Kirtland's warblers have bluish-grey upper body parts, with dark streaks on the back, yellow bellies, and dark streaks on the flanks and sides. It has black lores (cheeks) and a distinctive, large and conspicuous broken white eye ring, which it only shares with '' Setophaga coronata''. Females and juveniles are similar, but are browner on the wings and back and are not as boldly or brightly marked. It frequently bobs its tail up and down, which is uncommon in northern warblers. At and , it is the largest of the numerous warblers formerly classified in the genus ''Dendroica'' and is now the largest of the 35 or so species in the currently-accepted '' Setophaga'' genus. The Kirtland warbler has a wingspan of . Its mating song is a loud ''chip-chip-chip-too-too-weet-weet'' often sung from the top of a snag (dead tree) or northern pin oak ('' Quercus ellipsoidalis'') clump. This song can be heard over 400m away in good conditions. In its overwintering grounds it does not sing but makes loud "''chip''" noises from low in dense bushes. The eggs are a "delicate" pinkish white when fresh, fading to a dull white after a time. There are a few scattered sprinkles in various shades of brown and pink, these sprinkles and blotches concentrated at the top or form a sort of wreath at the larger end. The egg is not very glossy. It is 18 by 14mm in size. The shell is very thin.


Similar species

Baird compared and found it most similar to ''Setophaga coronata'', finding it best distinguishable by having a nearly uniformly yellow belly, no conspicuous yellow rump or crown, less black in the feathers of the crown, and a considerably larger and stouter bill and feet. Henninger mentions he finds it to have a certain resemblance to ''S. magnolia''. In The Bahamas it may be misidentified with ''S. dominica flavescens''.


Hybrids

In late October 1997 a large hybrid ''Setophaga'' warbler was netted in the low elevation dry scrublands of the southernmost
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 ...
, which based on
morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...
(plumage colour and anatomical measurements of size) and geography was most likely a hybrid between ''S. kirtlandii'' and ''S. fusca''.


Distribution

It was originally only known from Kirtland's home state of Ohio. In the mid 20th century the breeding range of Kirtland's warbler was reduced to a very limited area in the north of the Lower Peninsula of Michigan. In recent years, breeding pairs have been found in the
Upper Peninsula of Michigan The Upper Peninsula of Michigan—also known as Upper Michigan or colloquially the U.P. or Yoop—is the northern and more elevated of the two major landmasses that make up the U.S. state of Michigan; it is separated from the Lower Peninsula of ...
, Wisconsin, and southern Ontario due to the expanding population. The birds winter in Cuba, The Bahamas and the nearby
Turks and Caicos Islands The Turks and Caicos Islands (abbreviated TCI; and ) are a British Overseas Territory consisting of the larger Caicos Islands and smaller Turks Islands, two groups of tropical islands in the Lucayan Archipelago of the Atlantic Ocean and no ...
, where they are found on all islands investigated. A number also overwinter 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 ...
, in the Dominican Republic. Overwintering birds have been collected and sighted a number of times in
Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...
. It has been recorded as a rare accidental on
Bermuda Bermuda is a British Overseas Territories, British Overseas Territory in the Atlantic Ocean, North Atlantic Ocean. The closest land outside the territory is in the American state of North Carolina, about to the west-northwest. Bermuda is an ...
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 ...
, and there is an uncorroborated report from coastal
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 ...
. It has also been observed in the summer in
Québec Quebec is Canada's largest province by area. Located in Central Canada, the province shares borders with the provinces of Ontario to the west, Newfoundland and Labrador to the northeast, New Brunswick to the southeast and a coastal border ...
, although it is not known to breed there. Individuals first migrate from The Bahamas west to Florida and South Carolina in the second half of April to early May, and from there move further northwest and westwards until they reach the
Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...
, which they then follow upstream to the mouth of the
Ohio River The Ohio River () is a river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing in a southwesterly direction from Pittsburgh, Pennsylvania, to its river mouth, mouth on the Mississippi Riv ...
during May. They reach their breeding grounds early in June, and then leave their breeding range between August and October.


Ecology

The Kirtland's warbler's summer breeding habitat is in northern Michigan. Breeding habitat is where a bird lays its eggs and raises its babies. The Kirtland's warbler only builds its nests on the ground in young jack pine forests found in Michigan and sometimes Wisconsin.


Habitat

In their winter habitat, they have been found primarily in low "coppice" habitat, especially areas which have been cleared for
slash-and-burn Slash-and-burn agriculture is a form of shifting cultivation that involves the cutting and burning of plants in a forest or woodland to create a Field (agriculture), field called a swidden. The method begins by cutting down the trees and woody p ...
agriculture but have regrown after abandonment (98% of all records), with a preference for dense shrubbery with small openings here and there, no canopy and low ground cover. It has otherwise been found in all habitats on the islands, including, albeit uncommonly, suburban gardens and Bahamian pineyards, with the exception of high coppice which has never been clear cut -it has never been seen here. With rare exceptions this bird is almost always sighted from the ground to 3m high (98%). For breeding habitat it requires large areas of young jack pine on sandy soil. Kirtland's warblers occur in greatest numbers in large areas that have been clear cut or where a large wildfire has occurred. For breeding they require stands of young (6 to 20 year old, 2–4 m high) jack pine trees. Other common plants in this habitat are blueberry (''
Vaccinium angustifolium ''Vaccinium angustifolium'', commonly known as the wild lowbush blueberry, is a species of blueberry native to eastern and central Canada and the northeastern United States. It is the most common commercially used wild blueberry and is consider ...
''), sweet fern ('' Comptonia peregrina''), Canada mayflower ('' Maianthemum canadense'') and various grasses. Although it was initially believed to exclusively require jack pine stands, more recent research has found that the bird will also breed in some places in young stands of red pine (''
Pinus resinosa ''Pinus resinosa'', known as red pine (also Norway pine in Minnesota), is a pine native to Eastern North America. Description Red pine is a coniferous evergreen tree characterized by tall, straight growth. It usually ranges from in height and ...
'') of 10 to 15 years old. When the pine stands grow so tall so as to lose their lowest branches near the forest floor, the environment no longer provides sufficient cover. Such stands are ideally densely stocked with young pines, but also contain small occasional patches of open areas or with sparse tree cover.


Controversy

The status of the overwintering habitat has been contentious, with researchers disagreeing. Mayfield (1992, 1996) first stated that the bird inhabits the shrub layer. Lee ''et al''. (1997) also believed that the warbler inhabits shrubs, but they concluded that the species is entirely dependent on pineyards, stating that before the advent of
deforestation Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...
of the high coppice after the colonisation of The Bahamas by pre-colonial
Lucayan people The Lucayan people ( ) were the original residents of The Bahamas and the Turks and Caicos Islands before the European colonisation of the Americas. They were a branch of the Taínos who inhabited most of the Caribbean islands at the time. The ...
s, the bird must have been restricted to the northwestern islands which harbour these pineyards and absent from central, eastern and southern islands such as
Eleuthera Eleuthera () refers both to a single island in the archipelagic state of the The Bahamas, Commonwealth of the Bahamas and to its associated group of smaller islands. Eleuthera forms a part of the Great Bahama Bank. The island of Eleuthera incor ...
. Sykes and Clench (1998), basing their analysis on 96 unambiguous records of both collected specimens and observations on thirteen different islands, as well as almost 451 observations over three months of the same two banded individuals on Eleuthera, refuted the claim, finding that by far most records were from regrown coppice after abandonment of agricultural fields. Like Mayfield, they state many of the earlier records used by Lee ''et al''. were tainted by misidentification with ''S. dominica flavescens'', a similar-looking subspecies that was not adequately described or illustrated at the time of the recordings. A few months later, Haney ''et al''. (1998) published a repudiation of Sykes and Clench based on 101 warbler records, wherein they claimed the warblers do not prefer scrub coppice and reiterated their earlier assertion that the primary habitat of the birds was pineyards. They went even further in concluding that the world population of the warbler was not limited by the situation in their breeding range in Michigan, but that historic fluctuations in their population were instead being determined by the status of the pineyards in Bahamas. A detailed study by Wunderle ''et al''. (2010) using a much larger sample size of new data from 153 capture sites and 499 observations, and investigations of the diet, found that Sykes and Clench had been correct, and there was no validity to the assertions of Lee, Walsh-McGehee and Haney. Jones ''et al''. (2013), researching the warbler on an island where pineyards had never grown, hypothesized that a sampling bias for birds in pineyards had skewed the results of the research presented by Haney ''et al''. Despite the evidence,
Birdlife International BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding i ...
, which performs 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 ...
assessments, has consistently shown preference for the Haney ''et al''. interpretation, stating that the conclusion that "changes in population have occurred contemporaneously with the degradation and recovery of the north Bahamas pine ecosystem" is more compelling than that the recovery efforts in Michigan were having effects on the population size. Haney ''et al''. stated that another reason that this warbler was most likely restricted to the pineyards habitat was because there was no low coppice habitat available until the arrival of the first human colonists on the islands, the Lucayans some 1,000 years ago, due to there being no mechanism that could destroy the natural high coppice of the islands. However, in 2007, Wunderle ''et al.'' pointed out that
hurricane A tropical cyclone is a rapidly rotating storm system with a low-pressure area, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its ...
s might produce such young successional habitat, albeit with no empirical evidence; they theorized that perhaps this warbler species had specifically evolved to take advantage of such weather phenomena.


Behaviour

Yearlings and first-time breeders explore to find new breeding grounds, but ringed males have been observed to loyally return to the same nesting locality years after year; a male first ringed at CFB Petawawa in Ontario in 2006 returned for six consecutive years. This individual is estimated to have reached the age of nine, but in general the species are thought to have much shorter lifespans; males usually become four years old, and females are thought to only survive for 2.5 years on average. One study found that 85% of the singing males are able to attract mates. A warbler occupies a breeding territory of 2.7 to 3.4ha depending on location, but a larger wintering territory of 6.9 to 8.3ha depending on the island. They construct their nests on the ground, well concealed by lowest living branches of the jack pines and other vegetation. The nest is usually at the base of a tree, next to a down log or other structure. Eggs are laid in May to June.


Diet

It depends heavily during overwintering on the berries of '' Lantana involucrata'', which is a very common successional shrub a few years after agriculture has been abandoned in a particular field. It is also said to eat the berries of '' Erithalis fruticosa'' and '' Chiococca alba''. Of 331 observations of two warblers on Eleuthera in 1986, 76% were of foraging on ''Lantana'', 8% were in '' Tournefortia volubilis'', 4% in snowberry, 3.5% in '' Acacia rigens'', 3.3% in ''Erithalis'', 1.8% in ''
Zanthoxylum fagara ''Zanthoxylum fagara'' or wild lime, is a species of flowering plant that—despite its name—is not part of the genus ''Citrus'' with real limes and other fruit, but is a close cousin in the larger citrus family, Rutaceae. It is more closely ...
'', and 1% ''
Casuarina equisetifolia ''Casuarina equisetifolia'', commonly known as coastal she-oak, horsetail she-oak, ironwood, beach sheoak, beach casuarina, whistling tree or Australian pine is a species of flowering plant in the family Casuarinaceae and is native to Australia, ...
''. Plants they were found foraging in at less than 1% were '' Sideroxylon salicifolium'', '' Pithecellobium keyense'', '' Tabebuia bahamensis'' and '' Scleria lithosperma''. In its summering range this species feeds on blueberries and on insects such as spittlebugs, aphids and ants.


Interactions with other species

Jack pine is a species of pine with a distribution that spans almost across North America. Its cones open only after trees have been cleared away by forest fires or, after logging, in the summer sun. The ice age climate was somewhat drier overall and almost all of its present-day range was covered by solid ice as late as 10,000 to 15,000 years ago. Pollen analysis shows that the jack pine was almost non-existent between the
Appalachian Mountains The Appalachian Mountains, often called the Appalachians, are a mountain range in eastern to northeastern North America. The term "Appalachian" refers to several different regions associated with the mountain range, and its surrounding terrain ...
and the
Great Plains The Great Plains is a broad expanse of plain, flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include th ...
during this period, with the possible exception of tiny isolated relict populations, which presents a mystery as to where the Kirtland's warbler survived during this period. Mayfield suggests that the species was restricted during this age to the southeastern Atlantic coast, which might explain its modern overwintering range in the Bahamas as opposed to Mexico, as well as why it appears to be closer related to Caribbean warbler species. The jack pine and the warbler likely colonized the Midwest around 10,000 years ago. Without human intervention, the warblers are severely impacted by nest parasitism by the brown-headed cowbird. Blue jays prey on the nests and are a nuisance species because individual jays repeatedly allow themselves to get caught in the same traps used to exterminate the cowbirds of the nesting region.


Conservation

The Kirtland's Warbler Conservation Team is an integral part of post-delisting monitoring efforts and provides an important forum for sharing information, coordinating management efforts and ensuring that effective adaptive management occurs.


Decline

As global climate changed after the ice age through the last 10 millennia or so, jack pine, and consequently also Kirtland's warbler, shifted their habitat north. The cold-hardy jack pine now grows as far as north as the
Northwest Territories The Northwest Territories is a federal Provinces and territories of Canada, territory of Canada. At a land area of approximately and a 2021 census population of 41,070, it is the second-largest and the most populous of Provinces and territorie ...
. The Kirtland's warbler has historically always been rare, with the species first recorded quite late for a bird from the eastern USA between the 1840s to 1851, only four or five birds seen in the first two decades after, and the breeding grounds and first nest not recorded in 1903 in Michigan. It is still unclear to scientists how a species with such narrow habitat requirements was able to survive to modern times. One theory is that during the ice ages, which lasted much longer than
interglacials An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...
, Kirtland's warbler had a more stable distribution and habitat; i.e. the species exists as a glacial relict during geologically brief periods of warming global temperatures. It is quite possible that colonization by Europeans actually temporarily boosted populations of the bird. Most of the Lower Peninsula of Michigan was once covered in vast tracts of old growth white pine (''
Pinus strobus ''Pinus strobus'', commonly called the eastern white pine, northern white pine, white pine, Weymouth pine (British), and soft pine is a large pine native to eastern North America. It occurs from Newfoundland (island), Newfoundland, Canada, west ...
''), the final stage of
succession Succession is the act or process of following in order or sequence. Governance and politics *Order of succession, in politics, the ascension to power by one ruler, official, or monarch after the death, resignation, or removal from office of ...
in the woodlands of that region, but these were all harvested by the early 19th century for construction in the growing cities and towns around the
Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes spanning the Canada–United States border. The five lakes are Lake Superior, Superior, Lake Michigan, Michigan, Lake Huron, H ...
and along the East Coast. This created the conditions for the extensive woodlots of jack pine, a
pioneer species Pioneer species are resilient species that are the first to colonize barren environments, or to repopulate disrupted biodiverse steady-state ecosystems as part of ecological succession. Various kinds of events can create good conditions for pi ...
, found today. In 1871, fed by dry conditions, high winds and piles of logging slash, a massive forest fire swept through lower Michigan, with another largefire in
The Thumb The Thumb is a region and a peninsula of the U.S. state of Michigan, so named because the Lower Peninsula of Michigan, Lower Peninsula is shaped like a mitten. The Thumb area is generally considered to be in the Central Michigan region, east of t ...
of the Lower Peninsula, and a further huge forest fire on the Wisconsin-Michigan border and yet another around
Windsor, Ontario Windsor ( ) is a city in southwestern Ontario, Canada. It is situated on the south bank of the Detroit River directly across from the U.S city of Detroit, Detroit, Michigan. Geographically located within but administratively independent of Esse ...
. In 1881 another massive conflagration burned down the forests in The Thumb, which eliminated the last of the original white pine woodlands of Michigan. This period coincides with the era where most Kirtland's warbler specimens were collected, reflecting a possible peak in population size. However ornithologists were then unaware where it bred, and almost all these birds were taken in The Bahamas and Turks and Caicos or along the migration route. While no warblers were seen or killed in The Bahamas by the collector Henry Bryant in the 1850s and 1860s (despite his extensive searches), many dozens of warblers were recorded on almost all of the islands by the 1880s and 1890s. Charles Johnson Maynard collected 24 from
New Providence New Providence is the most populous island in The Bahamas, containing more than 70% of the total population. On the eastern side of the island is the national capital, national capital city of Nassau, Bahamas, Nassau; it had a population of 246 ...
during one two and a half month excursion in 1884. Maynard was a prolific collector, securing in this and subsequent years another ten on the same island almost a dozen on Eleuthera, and a further two on Cat Island, but many other collectors were able to obtain quite a number of specimens in The Bahamas during these decades. In July 1903, the
taxidermist Taxidermy is the art of preserving an animal's body by mounting (over an armature) or stuffing, for the purpose of display or study. Animals are often, but not always, portrayed in a lifelike state. The word ''taxidermy'' describes the process ...
Norman Asa Wood was presented with a specimen by a student at the
University of Michigan The University of Michigan (U-M, U of M, or Michigan) is a public university, public research university in Ann Arbor, Michigan, United States. Founded in 1817, it is the oldest institution of higher education in the state. The University of Mi ...
, and promptly travelled to the area it was killed, where he found the first nest ever recorded for the species near the banks of the Au Sable River. He also found a second nest; both nests had chicks and one held a single unhatched egg. Wood killed all the birds he could (eight managed to escape his gun), and secured the nests and egg. He tried to rear some of the chicks, but these soon died. Including chicks, he returned to the city with fifteen specimens, the biggest collection of the species at the time in the USA. It was thus one of the last bird species of North America to have its nesting habits discovered. The following year Edward Arnold travelled to a nearby locality in June and found the third nest ever, with four eggs. He was able to capture both the male and female on the nest simply with his hands. Including these, 25 birds had been taken in Michigan by 1904, and another eight recorded, which made it clear that Michigan was the main stronghold of the breeding range of this warbler. Considering the vernacular name of this bird was "jack pine bird" in Michigan, Wood was certainly not the first to discover that this species is specifically resident in jack pines, but in 1904 he was the first to publish these findings in a scientific journal. Woods also noted that, even in its breeding haunts, the bird was quite rare, and was not present in all areas of jack pine. This same year the migration route was first detailed in a paper by Charles C. Adams. Adams used dates of records of this bird in different states to show it migrated according to a very tight schedule, but used quite a broad route north spanning from the
Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...
to
South Carolina South Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders North Carolina to the north and northeast, the Atlantic Ocean to the southeast, and Georgia (U.S. state), Georg ...
. He thought this might indicate that there were more breeding grounds to the west and east than those in Michigan which Woods had publicised. The records Adams was using are from the 1880s and 1890s and birds were shot as far west as Missouri and Minnesota, areas where the species has not been seen since. In the 1920s, a recognised expert on this species was a
Chicago Chicago is the List of municipalities in Illinois, most populous city in the U.S. state of Illinois and in the Midwestern United States. With a population of 2,746,388, as of the 2020 United States census, 2020 census, it is the List of Unite ...
teenager named Nathan F. Leopold (most well known for being one half of the crime pair Leopold and Loeb) who, in his scientific journal articles, published a number of important discoveries. One was that the age of the jack pines in a stand is the most pertinent determinant in the suitability of a particular terrain as a breeding habitat for the species, and another discovery was that the population was subject to a deleterious
brood parasitism Brood parasitism is a subclass of parasitism and phenomenon and behavioural pattern of animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the ...
by the brown-headed cowbird. Kirtland's warbler is highly susceptible to nest parasitism by this cowbird. Brown-headed cowbirds feed mostly on seeds from grasses and weeds, with some crop grains. Insects such as grasshoppers and beetles, often caught as cows and horses stir them into movement, make up about a quarter of a cowbird's diet. Development and fragmentation of forests in the eastern United States have allowed brown-headed cowbirds to greatly expand their range eastward. One study from 1931 to 1971 found 59% of the warbler nests parasitised in comparison to 5% of the nests in the study area of all other bird species combined, another study found 48% from 1903 to 1949; another found 86% rate of parasitism; and a last study found 69% of the warbler nests afflicted from 1957 to 1971. In 1971 the third decennial census counted 201 singing males, whereas the 1961 census had found 501 breeding pairs, showing a 60% decrease in population over the 1960s. The first census of the species was performed in 1951, organised in part by a young
Harold F. Mayfield Harold Ford Mayfield (25 March 1911 – 27 January 2007) was an American business executive and amateur ornithologist who made a major study of Kirtland's warbler and worked for the preservation of their breeding areas. During his study of the war ...
, who would eventually spend the rest of life researching this species. 432 males were counted, half of these in just two areas where fires had raged in the 1930s. The second of what was supposed to be a decennial census program in 1961 showed an increase in population, with 502 males counted; many of these were still found at the sites of the two 1930s fires, a quarter was now resident at the site of a large fire from 1946. The population reached a low of 167 singing males in 1974, and in 1994 only of suitable breeding habitat was available.


Recovery

It was listed as endangered in the US in 1967. In 1971 a recovery plan was developed. The plan entailed the management of state and federal land through clear cutting, controlled burning and planting jack pine to expand suitable nesting habitat for Kirtland's warbler, as well as having the government acquire more land for this purpose. The other components were to limit public access land during nesting season, to conduct annual censuses of the warbler population, and lastly to intensively control the cowbird population. A 1966 study found that shooting and trapping the cowbirds could reduce parasitism from 65% to 21%, and in 1972 cowbird control efforts commenced. The cowbird traps were 4 by 4 ft. and 6 ft. high with a recessed entrance hole at the top, and worked using sunflower seed bait, tape recorders playing birdsongs and decoy cowbirds which attracted more cowbirds. Cowbirds are asphyxiated in plastic bags using car exhaust fumes. Once a day during breeding season, or when the traps had collected 30 to 40 birds, the traps were serviced to destroy cowbirds. Other trapped bird species were banded and released, and some twelve cowbirds were left in the trap as decoys. Less cowbirds are caught as the season progresses, and radio-tracked cowbirds indicate that females are sedentary during the season. In the first year, 1972, 2,200 cowbirds were eliminated using a single trap, and only 6% of the warbler nests in the region were parasitised compared to 69% previously. Average clutch size in the region almost doubled. In 1973 the program was expanded to four traps, which caught 3,300 cowbirds and resulted in no parasitism that year. That same year 216 singing male warblers were recorded an increase of 9.2% from the 200 males recorded in 1972, and the first increase recorded ever. Thus the control program was considered a success, and the following year 22 cowbird traps were deployed, removing over 4,000 cowbirds across the region. Although only 167 singing male warblers were recorded in 1974, nevertheless the large number of fledglings meant the traps were effective. As of 2016, the cowbird traps still capture 4,000 cowbirds a season. Effective blue jay management involves transporting a few hundred jays a year dozens of miles away to be released. Today the habitat of Kirtland's warbler is no longer being preserved by prescribed burns as these have proved too difficult to control (a forest service employee named James Swiderski was immolated during one of these burns in 1980),Radio La
Weighing Good Intentions
/ref> and the species is entirely dependent on staggered harvests by the
timber Lumber is wood that has been processed into uniform and useful sizes (dimensional lumber), including beams and planks or boards. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, window frames). ...
industry for its survival. Some 76,000 hectares are reserved for this purpose on the Lower Peninsula of Michigan, of which some 15,000 are maintained as young jack pine breeding habitat for the bird. The Michigan Department of Natural Resources, the U.S. Fish and Wildlife Service and the U.S. Forest Service coordinate the clear cutting of tracts of 50 year old jack pines on 23 Kirtland's warbler management units. These managed units total . After cutting new trees are planted in a specified pattern to mimic the natural habitat the warbler needs, with clearings and dense thickets. In 2004 Kirtland's warbler had been observed in Ontario and the Upper Peninsula of Michigan, and rarely recorded in northwest Ohio, where the numbers of recorded birds are increasing.Ohio Ornithological Society (2004)
Annotated Ohio state checklist
Beginning in 2005 a small number have been observed in Wisconsin. In 2007 three Kirtland's warbler nests were discovered in central Wisconsin
United States Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is a List of federal agencies in the United States, U.S. federal government agency within the United States Department of the Interior which oversees the management of fish, wildlife, ...
(2007)
Kirtland's Warbler 2007 Nesting Season Summary
. Version of 2007-DEC-10. Retrieved 2008-FEB-19.
and one at CFB Petawawa in Ontario, CFB Petawawa (2007)
Canada's Rarest Nesting Bird found at CFB Petawawa
Version of 2007-Nov-01. Retrieved 2008-FEB-19.
providing a sign that they are recovering and expanding their range once again. The Wisconsin population continues to grow, with 53 individuals and twenty nests recorded in 2017. In 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 Kirtland's warbler was classified as vulnerable to extinction since 1994, but was listed as
near threatened A near-threatened species is a species which has been Conservation status, categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to Endangered species, endangerment in the ne ...
in 2005 due to its recovery. Although there seemed to be no more than 5,000 Kirtland's warblers as of late 2007, four years earlier they had numbered just 2500–3000. Since the recovery plan began in the 1970s, the numbers of Kirtland's warbler have steadily risen, with an estimated population of 5,000 in 2016. A world total of 2,365 singing males were reported in the 2015 census. By 2018 there were an estimated 2,300 pairs and the population had continued to grow over the previous sixteen years according to the U.S. Fish and Wildlife Service Midwest Region. In 2019 the population has been above the recovery goal of 1,000 pairs for seventeen years. The birds depend on The Bahamas and adjacent territories during winter; in 1998 their winter habitat was judged to be extremely widespread and it was calculated that there is enough area and habitat in the Bahamas to house a population of roughly more than 500,000 birds. The most destructive threat in the winter range are thought to be house cats, at least on some islands. If Haney ''et al''. are correct in arguing that the species does not overwinter in scrub coppice habitats in The Bahamas, but instead in pineyards, and the abundance of this species is in fact limited by changes in this pineyard habitat, the conservation efforts in Michigan may be insufficient for species recovery. Some Michigan locals have questioned the cost and point of the program. Habitat and cowbird management cost $1 million per year as of 2003. In the 1990s this was garnered from a
carbon sequestration Carbon sequestration is the process of storing carbon in a carbon pool. It plays a crucial role in Climate change mitigation, limiting climate change by reducing the amount of Carbon dioxide in Earth's atmosphere, carbon dioxide in the atmosphe ...
fund, but that source of financing has been terminated. Management costs were estimated at $1.5 to 2 million per year in 2008, however, the payments by timber companies for the sale of jack pine for manufacturing paper and wood pulp offsets some costs, and the species brings bird-watching tourists to the region which is an economic boon to local businesses. Survival of this species will require management that will need to continue in perpetuity. An endowment fund to ensure a permanent funding source for the species has been discussed as an option. There is a Kirtland's warbler festival in Roscommon, Michigan, which is sponsored in part by Kirtland Community College (which is named in honour of the bird). The festival is held annually during the first full weekend of June.


Canada

Until 2007 Kirtland's warblers had never been known to have bred in Canada, with the exception of one ambiguous possible record from near Midhurst, Ontario in 1945. The first bird was collected in the country in 1900 when a specimen was secured on Toronto Island. The bird was then seen in the country in 1916 at the army base of CFB Petawawa by a military dentist, Paul Harrington; the same dentist made the third sighting of Canada at the same location in 1939, and in the next 65 years a bit more than two dozen sightings of the bird were made in the country, although only a few are verified. In 1979 it was declared an endangered species of Canada on the basis that it may have once bred in Ontario. In 2006 suddenly three birds were recorded at Petawawa, and the subsequent year the first ever nest was recorded at the same locality. The habitat at this location appears to have been maintained due to fires stemming from military training exercises. After 2007 the bird has bred almost every year at Petawawa, with the birds here fledged 27 young by 2014, and it has been reported at additional locations in central Ontario. The government of Ontario published a recovery strategy for the Kirtland's warbler in 2016. A new mixed red and jack pine stand was planted at a location in
Simcoe County Simcoe County is a county and census division located in the central region of Ontario, Canada. The county is located north of the Greater Toronto Area, and forms the north western edge of the Golden Horseshoe. The county seat is located in Mi ...
in 2018 in the hopes of attracting the warbler, of which a sighting in the area had earlier been reported. Red pine was interspersed with the jack pine because the latter is relatively worthless as lumber, and it was hoped this configuration would make the project more economically sustainable.


Delisting

Prior to being delisted from the United States Fish and Wildlife Service list of endangered mammals and birds in 2019,https://www.fws.gov/Midwest/endangered/birds/Kirtland/index.html , Kirtland's warbler (''Setophaga kirtlandii'') Status: Delisted the Kirtland's warbler had been listed as "endangered" under the
Endangered Species Act The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of e ...
of 1973.U.S. Fish and Wildlife Service Species Profile for Kirtland's Warbler
. Ecos.fws.gov. Retrieved on 2013-04-03.
Since delisting, continued monitoring is being used to ensure that the species remains secure.


Protected areas

It has been regularly recorded in the following
protected areas Protected areas or conservation areas are locations which receive protection because of their recognized natural or cultural values. Protected areas are those areas in which human presence or the exploitation of natural resources (e.g. firewoo ...
: * Abaco National Park, Abaco, The Bahamas. *
Algonquin Provincial Park Algonquin Provincial Park is an Ontario Ontario Parks, provincial park located between Georgian Bay and the Ottawa River, mostly within the Nipissing, Unorganized, South Part, Ontario, Unorganized South Part of Nipissing District. Established i ...
,
Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...
, Canada. * Huron-Manistee National Forests, Michigan, USA. * Lucayan National Park,
Grand Bahama Grand Bahama is the northernmost of the islands of the Bahamas. It is the third largest island in the Bahamas island chain of approximately 700 islands and 2,400 cays. The island is roughly in area and approximately long west to east and at it ...
, The Bahamas. *
Point Pelee National Park Point Pelee National Park (; ) is a National parks of Canada, national park in Essex County, Ontario, Essex County in southwestern Ontario, Canada where it extends into Lake Erie. The word is French for 'bald'. Point Pelee consists of a peninsu ...
,
Essex County, Ontario Essex County is a primarily rural county in Southwestern Ontario, Canada comprising seven municipalities: Amherstburg, Kingsville, Ontario, Kingsville, Lakeshore, Ontario, Lakeshore, LaSalle, Ontario, LaSalle, Leamington, Ontario, Leamington, Tec ...
, Canada. * Rand Nature Centre (as Pinelands Wilderness Sanctuary), Grand Bahama, The Bahamas. * Tawas Point State Park, Michigan, USA.


See also

*
Mutualism (biology) Mutualism describes the ecological Biological interaction, interaction between two or more species where each species has a net benefit. Mutualism is a common type of Ecology, ecological interaction. Prominent examples are: * the nutrient exch ...
* Kirtlands Warbler Wildlife Management Area


References


Further reading

*Clench, Mary Heimerdinger (1973). "The Fall Migration Route of Kirtland's Warbler". ''Wilson Bulletin'' 85 (4): 417–428. * *Mayfield, Harold (1960). "The Kirtland's Warbler". ''Cranbrook Institute of Science Bulletin'' (40): 1–242. * .


External links

* * http://www.uptownupdate.com/2015/05/rare-bird-alights-at-montrose-harbor.html
Kirtland's warbler
at All About Birds





* {{Authority control
Kirtland's warbler Kirtland's warbler (''Setophaga kirtlandii''), also known in Michigan by the common name jack pine bird, or the jack pine warbler, is a small songbird of the New World warbler family (biology), family (Parulidae). Nearly Extinction, extinct just ...
Native birds of the Eastern United States Environment of Michigan Endangered fauna of the United States
Kirtland's warbler Kirtland's warbler (''Setophaga kirtlandii''), also known in Michigan by the common name jack pine bird, or the jack pine warbler, is a small songbird of the New World warbler family (biology), family (Parulidae). Nearly Extinction, extinct just ...
ESA endangered species
Kirtland's warbler Kirtland's warbler (''Setophaga kirtlandii''), also known in Michigan by the common name jack pine bird, or the jack pine warbler, is a small songbird of the New World warbler family (biology), family (Parulidae). Nearly Extinction, extinct just ...