Swainson's Warbler
Encyclopedia
Swainson's Warbler, Limnothlypis swainsonii, is a small species
of New World warbler
. It is monotypic
, the only member of the genus
Limnothlypis.
, there is no difference in appearance between a male or female Swainson's warbler.
lands and canebrake
s of the south-eastern
United States
. More rarely, they will also occur in rhododendron
thickets in the southern Appalachian mountains
. They are a migratory
species, with part of the population migrating southeastwards to the Greater Antilles
and the other southwestwards to the Yucatán Peninsula
region in winter.
. These birds live to as old as 8 years (Graves in Winker et al. 2000).
are recognized. There appears to be some divergence between populations from Arkansas
and others of the coastal plains. This does fit a pattern one would expect from genetic drift
, but there seem to be no geographical or ecological barriers restricting gene flow
. Even during the last ice age, when average temperatures, precipitation
and sea level
s were lower, there seems to have been ample contiguous habitat
. Clearly, some factor restricting gene flow is at work, but it is not presently known what it is. It is possible that the subpopulations conform to the different wintering areas.(Winker et al. 2000)
In some migrant birds it is known that the initial direction of the migration is set by fairly simple hereditary mechanisms. Offspring of pairs comprising birds of different subpopulations will, in such species, attempt to migrate into an intermediate direction. Such a course would lead a Swainson's Warbler deep into the Caribbean
where there are no wintering or even stopover points, and the bird would almost certainly perish. More research such as analyzing bird banding data is needed to determine whether this mechanism applies in Swainson's Warbler.(Winker et al. 2000)
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of New World warbler
New World warbler
The New World warblers or wood-warblers are a group of small, often colorful, passerine birds restricted to the New World. They are not related to the Old World warblers or the Australian warblers....
. It is monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
, the only member of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Limnothlypis.
Description
A small and rather non-descript species of New World warbler, Swainson's Warblers will grow to about 5 to 6½ inches (about 13–16 cm) in length and 15 grams (Graves in Winker et al. 2000) in weight. They are a plain olive-brown above and pale yellow-white below. They have a whitish eyebrow stripe that runs above their eye, and the top of their head is a rusty brown. Unlike most other New World warblers that are mostly dimorphicSexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, there is no difference in appearance between a male or female Swainson's warbler.
Distribution and habitat
Swainson's Warblers are uncommon, mostly found in flooded swampSwamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
lands and canebrake
Canebrake
Canebrake is an English noun meaning an area of land with a thick dense growth of cane, sugarcane, exotic bamboo, or similar plant material.Canebrake may also refer to:Places in the United States of America:*Canebrake...
s of the south-eastern
Southeastern United States
The Southeastern United States, colloquially referred to as the Southeast, is the eastern portion of the Southern United States. It is one of the most populous regions in the United States of America....
United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. More rarely, they will also occur in rhododendron
Rhododendron
Rhododendron is a genus of over 1 000 species of woody plants in the heath family, most with showy flowers...
thickets in the southern Appalachian mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...
. They are a migratory
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, with part of the population migrating southeastwards to the Greater Antilles
Greater Antilles
The Greater Antilles are one of three island groups in the Caribbean. Comprising Cuba, Jamaica, Hispaniola , and Puerto Rico, the Greater Antilles constitute almost 90% of the land mass of the entire West Indies.-Greater Antilles in context :The islands of the Caribbean Sea, collectively known as...
and the other southwestwards to the Yucatán Peninsula
Yucatán Peninsula
The Yucatán Peninsula, in southeastern Mexico, separates the Caribbean Sea from the Gulf of Mexico, with the northern coastline on the Yucatán Channel...
region in winter.
Breeding
This species begins breeding at about 10 months of age (Graves in Winker et al. 2000). Pairs form and stake out and defend a territory for nesting. Nests are fairly large and bulky, constructed from moss, grass, and small leaves situated above ground in a tangle of tall reeds or vines. The female will lay between 3 to 5 eggs. The eggs are white and sometimes, but rarely, speckled with brown. Incubation is done by the female only and lasts for about 14 days, after which the eggs will hatch. The young leave the nest about 12 days after they have hatched. It is not known how long pairs stay together, although once a pair-bond has been established they do not usually mate with other birds at least in the current nesting seasonNesting season
The nesting season is the time of year during which birds and some other animals, particularly some reptiles, build nests, lay eggs in them, and in most cases bring up their young. It is usually in the spring....
. These birds live to as old as 8 years (Graves in Winker et al. 2000).
Taxonomy
No subspeciesSubspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
are recognized. There appears to be some divergence between populations from Arkansas
Arkansas
Arkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River...
and others of the coastal plains. This does fit a pattern one would expect from genetic drift
Genetic drift
Genetic drift or allelic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces...
, but there seem to be no geographical or ecological barriers restricting gene flow
Gene flow
In population genetics, gene flow is the transfer of alleles of genes from one population to another.Migration into or out of a population may be responsible for a marked change in allele frequencies...
. Even during the last ice age, when average temperatures, precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
and sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...
s were lower, there seems to have been ample contiguous 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...
. Clearly, some factor restricting gene flow is at work, but it is not presently known what it is. It is possible that the subpopulations conform to the different wintering areas.(Winker et al. 2000)
In some migrant birds it is known that the initial direction of the migration is set by fairly simple hereditary mechanisms. Offspring of pairs comprising birds of different subpopulations will, in such species, attempt to migrate into an intermediate direction. Such a course would lead a Swainson's Warbler deep into the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
where there are no wintering or even stopover points, and the bird would almost certainly perish. More research such as analyzing bird banding data is needed to determine whether this mechanism applies in Swainson's Warbler.(Winker et al. 2000)
External links
- Photo linked at www.natureserve.org for Swainson's Warbler
- Swainson's Warbler photo gallery VIREO Photo-High Res--(Close-up)
- Swainson's Warbler Bird Sound