Tesia
Encyclopedia
The tesias are a genus, Tesia, of Old World warbler
. The genus was once included in the large family
Sylviidae
but recent research placed it within the new family Cettiidae
. The genus has a discontinuous distribution in East and South East Asia. The three northern species range widely across southern China, Burma, Northern Thailand and Laos and into India, southern Nepal and Vietnam; whereas the other two species are found in Java
and the Lesser Sundas in southern Indonesia
. One species of tesia, the Chestnut-headed Tesia
, which occupies the northern area of the genus' range, is sometimes split into the genus Oligura. The Russet-capped Tesia
was once considered to be a race of the Timor Stubtail
, Urosphena subulata. The three northern species are sometimes known as ground-warblers.
Tesias are tiny ground-living warblers which range in length from 7–10 cm and weigh between 6-12 g. They have long legs and an upright stance, and appear to almost lack a tail, as their tail retrices are shorter than the tail coverts. The plumage
of the northern species (except the Chestnut-headed) is olive backs and wings and grey bellies (darker slate in the Slaty-bellied Tesia
); the southern species have brown wings and backs. All species have an eye-stripe and all except the Slaty-bellied Tesia have a supercillium; this is most prominent in the Javan Tesia
. The plumage of the Chestnut-headed Tesia is different from the other species; it has a bright yellow belly, chest and throat, and a deep chestnut coloured head and an incomplete white orbital ring. It lacks the facial stripes of the other species. The bill
of all species is long and bicoloured, with a dark upper mandible and a flesh-coloured lower one, as well as strong ridge on the upper mandible.
Tesias live in the undergrowth of forest, usually montane broadleaf forest. They have a preference for damp forests, and are often found near water, particularly the Chestnut-headed and Slaty-bellied Tesias, although they use a range of microhabitats within the forest, including patches of bamboo or nettles. The three northern species are altitudinal migrants
, breeding up to 4000 m but wintering as low as 150 m. The two southern species are resident within their range.
The tesias are active insectivores that usually feed near the ground amongst the undergrowth and leaf litter, but may forage as high as 25 m off the ground (in the case of the Russet-capped Tesia
) amongst the tangle of creepers on large tree trunks. The Slaty-bellied Tesia will move leaves around in the manner of a thrush
while foraging, and the Grey-bellied Tesia
has been recorded joining mixed-species feeding flock
s in the non-breeding season.
There is little information about the breeding biology of the tesias, only three species, the Grey-bellied, Chestnut-headed and Javan, have even had their nests described. They are seasonal breeders, with the Grey-bellied and Russet-capped Tesias nesting in May–July, and the Javan Tesia having two seasons, April–June and October to December. The nest
is a ball of moss for the Grey-bellied Tesia and plant fibres, moss and roots, and is fixed into vegetation or moss on the side of a tree, low down. The clutch size of the Grey-bellied Tesia is 3-5 eggs, but only 2 eggs for the Javan Tesia and Chestnut-headed Tesia. In the Chestnut-headed Tesia both sexes incubate the clutch; this species is also known to occasionally be parasitized by the Lesser Cuckoo
.
None of the tesias are considered to be threatened by human activities, and are all listed as least concern
by the IUCN. Even the island species, which have restricted ranges, are described as common within their ranges.
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...
. The genus was once included in the large family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
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...
but recent research placed it within the new family Cettiidae
Cettiidae
Cettiidae is a newly validated family of small insectivorous songbirds , formerly placed in the Old World warbler "wastebin" assemblage. It contains the typical bush-warblers and their relatives. As common name, cettiid warblers is usually used.Its members occur mainly in Asia and Africa, ranging...
. The genus has a discontinuous distribution in East and South East Asia. The three northern species range widely across southern China, Burma, Northern Thailand and Laos and into India, southern Nepal and Vietnam; whereas the other two species are found in Java
Java
Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...
and the Lesser Sundas in southern Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
. One species of tesia, the Chestnut-headed Tesia
Chestnut-headed Tesia
The Chestnut-headed Tesia is a songbird species formerly in the "Old World warbler" but nowadays placed in the bush warbler family ....
, which occupies the northern area of the genus' range, is sometimes split into the genus Oligura. The Russet-capped Tesia
Russet-capped Tesia
The Russet-Capped Tesia is a species of Old World warbler in the Cettiidae family. The scientific name commemorates British colonial administrator and zoological collector Alfred Hart Everett.-References:...
was once considered to be a race of the Timor Stubtail
Timor Stubtail
The Timor Stubtail is a species of Old World warbler in the Sylviidae family.It is found in Indonesia and East Timor.-References:* BirdLife International 2004. . Downloaded on 10 July 2007....
, Urosphena subulata. The three northern species are sometimes known as ground-warblers.
Tesias are tiny ground-living warblers which range in length from 7–10 cm and weigh between 6-12 g. They have long legs and an upright stance, and appear to almost lack a tail, as their tail retrices are shorter than the tail coverts. The plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
of the northern species (except the Chestnut-headed) is olive backs and wings and grey bellies (darker slate in the Slaty-bellied Tesia
Slaty-bellied Tesia
The Slaty-Bellied Tesia is a species of warbler in the Cettiidae family.It is found in Bhutan, China, India, Laos, Myanmar, Nepal, Thailand, and Vietnam. Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montane forests.-References:* BirdLife...
); the southern species have brown wings and backs. All species have an eye-stripe and all except the Slaty-bellied Tesia have a supercillium; this is most prominent in the Javan Tesia
Javan Tesia
The Javan Tesia is a species of Old World warbler in the Cettiidae family.It is endemic to Java in Indonesia. The Javan Tesia is a small tesia with long legs and almost no tail. It feeds on insects in the undergrowth of broadleaf forests.-References:* BirdLife International 2004. . Downloaded...
. The plumage of the Chestnut-headed Tesia is different from the other species; it has a bright yellow belly, chest and throat, and a deep chestnut coloured head and an incomplete white orbital ring. It lacks the facial stripes of the other species. The bill
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
of all species is long and bicoloured, with a dark upper mandible and a flesh-coloured lower one, as well as strong ridge on the upper mandible.
Tesias live in the undergrowth of forest, usually montane broadleaf forest. They have a preference for damp forests, and are often found near water, particularly the Chestnut-headed and Slaty-bellied Tesias, although they use a range of microhabitats within the forest, including patches of bamboo or nettles. The three northern species are altitudinal migrants
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...
, breeding up to 4000 m but wintering as low as 150 m. The two southern species are resident within their range.
The tesias are active insectivores that usually feed near the ground amongst the undergrowth and leaf litter, but may forage as high as 25 m off the ground (in the case of the Russet-capped Tesia
Russet-capped Tesia
The Russet-Capped Tesia is a species of Old World warbler in the Cettiidae family. The scientific name commemorates British colonial administrator and zoological collector Alfred Hart Everett.-References:...
) amongst the tangle of creepers on large tree trunks. The Slaty-bellied Tesia will move leaves around in the manner of a 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...
while foraging, and the Grey-bellied Tesia
Grey-bellied Tesia
The Grey-bellied Tesia is a species of warbler in the Cettiidae family.It is found in Bangladesh, Bhutan, Cambodia, China, India, Laos, Myanmar, Nepal, Thailand, and Vietnam. Its natural habitat is subtropical or tropical moist montane forests.-References:* BirdLife International 2004. . ...
has been recorded joining mixed-species feeding flock
Mixed-species feeding flock
A mixed-species feeding flock, also termed a mixed-species foraging flock, mixed hunting party or informally bird wave, is a flock of usually insectivorous birds of different species, that join each other and move together while foraging...
s in the non-breeding season.
There is little information about the breeding biology of the tesias, only three species, the Grey-bellied, Chestnut-headed and Javan, have even had their nests described. They are seasonal breeders, with the Grey-bellied and Russet-capped Tesias nesting in May–July, and the Javan Tesia having two seasons, April–June and October to December. 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 a ball of moss for the Grey-bellied Tesia and plant fibres, moss and roots, and is fixed into vegetation or moss on the side of a tree, low down. The clutch size of the Grey-bellied Tesia is 3-5 eggs, but only 2 eggs for the Javan Tesia and Chestnut-headed Tesia. In the Chestnut-headed Tesia both sexes incubate the clutch; this species is also known to occasionally be parasitized by the Lesser Cuckoo
Lesser Cuckoo
The Lesser Cuckoo is a species of cuckoo in the Cuculidae family.It is found in Bangladesh, Bhutan, China, Democratic Republic of the Congo, Hong Kong, India, Japan, Kenya, North Korea, South Korea, Laos, Malawi, Myanmar, Nepal, Pakistan, Russia, Seychelles, Somalia, South Africa, Sri Lanka,...
.
None of the tesias are considered to be threatened by human activities, and are all listed as 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...
by the IUCN. Even the island species, which have restricted ranges, are described as common within their ranges.
Species
- Chestnut-Headed TesiaChestnut-headed TesiaThe Chestnut-headed Tesia is a songbird species formerly in the "Old World warbler" but nowadays placed in the bush warbler family ....
(Tesia castaneocoronata) - Slaty-Bellied TesiaSlaty-bellied TesiaThe Slaty-Bellied Tesia is a species of warbler in the Cettiidae family.It is found in Bhutan, China, India, Laos, Myanmar, Nepal, Thailand, and Vietnam. Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montane forests.-References:* BirdLife...
(Tesia olivea) - Grey-Bellied TesiaGrey-bellied TesiaThe Grey-bellied Tesia is a species of warbler in the Cettiidae family.It is found in Bangladesh, Bhutan, Cambodia, China, India, Laos, Myanmar, Nepal, Thailand, and Vietnam. Its natural habitat is subtropical or tropical moist montane forests.-References:* BirdLife International 2004. . ...
(Tesia cyaniventer) - Javan TesiaJavan TesiaThe Javan Tesia is a species of Old World warbler in the Cettiidae family.It is endemic to Java in Indonesia. The Javan Tesia is a small tesia with long legs and almost no tail. It feeds on insects in the undergrowth of broadleaf forests.-References:* BirdLife International 2004. . Downloaded...
(Tesia superciliaris) - Russet-Capped TesiaRusset-capped TesiaThe Russet-Capped Tesia is a species of Old World warbler in the Cettiidae family. The scientific name commemorates British colonial administrator and zoological collector Alfred Hart Everett.-References:...
(Tesia everetti)