Brown Songlark
Encyclopedia
The Brown Songlark also Australian Songlark, is a small passerine
bird
found throughout much of Australia
. A member of the Old World Warbler
family, the species is notable for sexual size dimorphism
, among the most pronounced in any bird. It is a moderate-sized bird of nondescript plumage; the female brownish above and paler below, the larger male a darker brown.
and Thomas Horsfield
as Megalurus cruralis in 1827. John Gould
placed it in the genus Cincloramphus in 1843, describing it as C. cantatoris.
However the specific name of the former authors took priority. It is a species of Sylviidae
, the Old World Warblers, a successful passerine family. It shares the genus Cincloramphus with the Rufous Songlark
, another species endemic to much of Australia.
The generic name Cincloramphus is derived from Greek
words cinclus/κιγκλος "wagtail" and ramphos/ραμφος "beak") and cruralis from the Latin
root crur- "leg, shin".
The Brown Songlark has a large range, between 1,000,000 and 10,000,000 kilometers²; while population size has not been quantified the bird is reported to be common. The IUCN thus lists it as a species of "least concern
" and it is considered "secure" by Australian authorities.
occurs from August to December. The nest itself is a deep cup of herbaceous material well concealed in shrubbery or tall grass. There is generally one clutch
per breeding season, consisting of 2 to 5 pale pink eggs with reddish brown spots and flecks 23 mm x 17 mm in size. Females provide most of the parenting. Foxes and snakes prey upon nests.
Research has shown an interesting corollary to the dimorphism of the species: though males are larger than females, females hatch from larger eggs and are initially heavier than their brothers. This may provide them an early competitive advantage. Particularly, in periods of low food availability, the greater nutrient reserves of female hatchlings may skew the sex-ratio toward "cheaper" daughters. Three weeks after hatching, male chicks are significantly heavier than the females. After ten days, the male chicks are almost 50% heavier than their sisters. This is due to the male nestlings receiving a higher quantity and quality of prey from their parents. The males receive more spiders than their sisters, providing them with certain amino acids that are essential for their growth and development. The females receive more grasshoppers than spiders, which contain chitin (the indigestible carbohydrate of the exoskeleton). Studies have shown that when raising all male chicks, the females energy expenditure increases by 27%. The favouritism shown to the male chicks is due to the importance of body size in males in regard to reproductive success, ensuring the parents genes are well represented in future generations.
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...
found throughout much of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. A member of the Old World Warbler
Old World warbler
The "Old World Warblers" is the name used to describe a large group of birds formerly grouped together in the bird family Sylviidae. The family held over 400 species in over 70 genera, and were the source of much taxonomic confusion. Two families were split out initially, the cisticolas into...
family, the species is notable for sexual size dimorphism
Sexual 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:...
, among the most pronounced in any bird. It is a moderate-sized bird of nondescript plumage; the female brownish above and paler below, the larger male a darker brown.
Taxonomy
The Brown Songlark was described by Nicholas Aylward VigorsNicholas Aylward Vigors
Nicholas Aylward Vigors was an Irish zoologist and politician.Vigors was born at Old Leighlin, County Carlow. He studied at Trinity College, Oxford. He served in the army during the Peninsular War from 1809 to 1811. He then returned to Oxford, graduating with a B.A. in 1815 and in 1817 with an...
and Thomas Horsfield
Thomas Horsfield
Thomas Horsfield M. D. was an American physician and naturalist.Horsfield was born in Bethlehem, Pennsylvania, and studied medicine at the University of Pennsylvania. He was the grandson of Timothy Horsfield, Sr., a colonel and justice of the peace in Bethlehem, and a friend mentioned in Benjamin...
as Megalurus cruralis in 1827. John Gould
John Gould
John Gould was an English ornithologist and bird artist. The Gould League in Australia was named after him. His identification of the birds now nicknamed "Darwin's finches" played a role in the inception of Darwin's theory of evolution by natural selection...
placed it in the genus Cincloramphus in 1843, describing it as C. cantatoris.
However the specific name of the former authors took priority. It is a species of Sylviidae
Sylviidae
Sylviidae is a family of passerine birds that was part of an assemblage known as the Old World warblers. The family was formerly a wastebin taxon with over 400 species of bird in over 70 genera. The family was poorly defined with many characteristics shared with other families...
, the Old World Warblers, a successful passerine family. It shares the genus Cincloramphus with the Rufous Songlark
Rufous Songlark
The Rufous Songlark is a species of Old World warbler endemic to Australia.-Taxonomy:It is a species of Megaluridae, the Old World Warblers, a successful passerine family. It shares the genus Cincloramphus with the Brown Songlark, another species endemic to Australia.The Rufous Songlark was...
, another species endemic to much of Australia.
The generic name Cincloramphus is derived from 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 cinclus/κιγκλος "wagtail" and ramphos/ραμφος "beak") and cruralis 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...
root crur- "leg, shin".
Description
Male Brown Songlarks are 23–25 cm long versus 18–19 cm for females, and may weigh 2.3 times as much. In general, the birds have a dusky pale- streaked with darker brown plumage with and pale eyebrows. The underparts are brownish-white in the female, darker brown in the male. Breeding males may display a cinnamon-colour. Its eyes and bill are black, and legs grey. Juveniles are smaller and paler with pinkish-brown bills. The call has been described as loud and creaky. The male is the principal singer, calling from perches or when rising above breeding territory.Distribution and habitat
The bird is found throughout all of Australia, except parts of the far north, and not in Tasmania. There are particularly dense populations in the southern parts of the country. It prefers open pastures and grassy scrub, and feeds on seeds and insects. The species is highly nomadic. Local numbers fluctuate depending on rainfall and the bird will often flee from drought affected areas.The Brown Songlark has a large range, between 1,000,000 and 10,000,000 kilometers²; while population size has not been quantified the bird is reported to be common. The IUCN thus lists it as a species 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...
" and it is considered "secure" by Australian authorities.
Reproduction
NestingNesting
Nesting refers to the process of efficiently manufacturing parts from flat raw material.Companies manufacturing parts from flat raw material such as sheet metal use a variety of technologies to perform this task. The sheet metal nesting for flat sheets and nesting for coils are different algorithms...
occurs from August to December. The nest itself is a deep cup of herbaceous material well concealed in shrubbery or tall grass. There is generally one clutch
Clutch (eggs)
A clutch of eggs refers to all the eggs produced by birds or reptiles, often at a single time, particularly those laid in a nest.In birds, destruction of a clutch by predators, , results in double-clutching...
per breeding season, consisting of 2 to 5 pale pink eggs with reddish brown spots and flecks 23 mm x 17 mm in size. Females provide most of the parenting. Foxes and snakes prey upon nests.
Sexual dimorphism
The sexual dimorphism of the species has been the subject of study. Males are highly polygynous and compete directly for mates, giving rise to the pronounced size differential. Preferring open terrain, there is significant habitat heterogeneity (sameness) and excellent visibility across Brown Songlark territories. This allows males to defend large territories and support multiple nesting females.Research has shown an interesting corollary to the dimorphism of the species: though males are larger than females, females hatch from larger eggs and are initially heavier than their brothers. This may provide them an early competitive advantage. Particularly, in periods of low food availability, the greater nutrient reserves of female hatchlings may skew the sex-ratio toward "cheaper" daughters. Three weeks after hatching, male chicks are significantly heavier than the females. After ten days, the male chicks are almost 50% heavier than their sisters. This is due to the male nestlings receiving a higher quantity and quality of prey from their parents. The males receive more spiders than their sisters, providing them with certain amino acids that are essential for their growth and development. The females receive more grasshoppers than spiders, which contain chitin (the indigestible carbohydrate of the exoskeleton). Studies have shown that when raising all male chicks, the females energy expenditure increases by 27%. The favouritism shown to the male chicks is due to the importance of body size in males in regard to reproductive success, ensuring the parents genes are well represented in future generations.