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Alethe choloensischolo alethe(Also: thyolo alethe)

By Tanya Dewey

Geographic Range

Alethe choloensis populations are found in disjunct forest fragments in southeastern Malawi and nearby Mozambique. They are known from approximately 16 forest fragments: 13 in Malawi and 3 in Mozambique. (BirdLife International, 2008; Barnes, et al., 2009)

Habitat

Cholo alethes are found in mid-altitude montane evergreen forests and in lower elevation habitats during the non-breeding season. An important habitat feature for these birds is the presence of ant nests, which are critical for their foraging habits. When ant nests are present, breeding pairs can persist in forest fragments as small as 0.5 hectares. (BirdLife International, 2008; Barnes, et al., 2009)

Physical Description

Cholo alethes have warm brown plumage that is a deep, rich tone on the back and becomes pale and grayish on their ventral surfaces. The chin and throat are white and the outer tail feathers are white. The plumage is grayish on the sides of the face and neck. They have long, pink or flesh-colored legs and toes and are approximately 16 cm in total length. They are thrush-like in general appearance. No sexual dimorphism is described. (BirdLife International, 2008; Barnes, et al., 2009; Marshall Cavendish Corporation, 2001)

  • Sexual Dimorphism
  • sexes alike
  • Average length
    16 cm
    6.30 in

Reproduction

No information on mating systems in cholo alethes have been reported. The literature does suggest that cholo alethes pair for mating, suggesting monogamy. (BirdLife International, 2008; Barnes, et al., 2009)

Cholo alethes seem to breed from September to January. Only 1 nest has been documented, it was placed in the fork of a tree 4 m above the ground. Other information on reproduction in this species is not reported in the literature. (BirdLife International, 2008; Barnes, et al., 2009)

  • Breeding interval
    Breeding interval is not known.
  • Breeding season
    Cholo alethes seem to breed from September to January.

No information on parental investment is reported in the literature. If pairs form for breeding, it can be assumed that male and female parents contribute to the protection and feeding of their young. Most young in the family Turdidae are altricial. (BirdLife International, 2008; Barnes, et al., 2009)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female

Lifespan/Longevity

There is no information on longevity in cholo alethes. Related birds of similar sizes can live up to 14 years in the wild.

Behavior

Observations suggest that cholo alethes forage on or near the forest floor among swarms of red ants. They may undergo small elevational migrations between higher elevation forests during the breeding season and lower elevation forests during the non-breeding season. (Marshall Cavendish Corporation, 2001)

Home Range

Home range sizes are not reported in cholo alethes.

Communication and Perception

Cholo alethes have melodic songs and a soft alarm called described as a "trrrp." (Barnes, et al., 2009)

Food Habits

Cholo alethes feed among ant swarms, catching the small arthropods that flee the oncoming mass of ants. It has also been suggested that they may consume ants that crawl onto their bodies when they are foraging near and within the swarm. They hop into swarms from logs or low branches and then quickly fly away again - at which point they make beak-clicking noises and flap their wings. (BirdLife International, 2008; Barnes, et al., 2009; Marshall Cavendish Corporation, 2001)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods

Predation

Predators on cholo alethes are not reported in the literature. (BirdLife International, 2008; Barnes, et al., 2009)

Ecosystem Roles

Cholo alethes have an important symbiotic relationship with ants, following ant swarms to take advantage of fleeing arthropods. They occupy a niche similar to the antbirds of the neotropics (Thamnophilidae).

Mutualist Species

Economic Importance for Humans: Positive

Cholo alethes are rare birds that may attract some ecotourism interest. They are important members of native ecosystems, exploiting a niche similar to the neotropical antbirds.

Economic Importance for Humans: Negative

There are no adverse effects of Alethe choloensis on humans.

Conservation Status

Cholo alethes are considered endangered by the IUCN red list. They are endemic to a very small range, fragmented populations, and high levels of habitat destruction via deforestation. Concerns about the rates of deforestation increasing in their range, caused some researchers to call for a new listing as critically endangered in the near future. Two populations were recently discovered in approximately 1600 hectares of montane forest on Mt. Chiperone and approximately 5000 hectares of evergreen forest on Mt. Mabu, both in Mozambique. These population increase estimated global population sizes. At least for the time being, those populations are not currently threatened with high levels of deforestation. It is likely that populations of cholo alethes have been shrinking with the reduction and fragmentation of tropical montane forests in Africa, as the extent of these forests has continued to shrink since the last glacial maxima, approximately 20,000 years ago. Humans have greatly hastened this habitat fragmentation and reduction in recent years. (BirdLife International, 2008; Barnes, et al., 2009; Marshall Cavendish Corporation, 2001; Spottiswoode, et al., 2008)

Some of the forest fragments occupied by cholo alethes are protected as forest reserves, although enforcement of land protection in these areas is often poor. An effort to protect Mulanje Mountain, in Malawi, will help to protect a substantial population of these birds. Efforts are underway to protect areas in Mozambique where cholo alethes are found. Current population estimates range from 2,500 to 10,000 individuals. (BirdLife International, 2008; Barnes, et al., 2009)

Other Comments

Beresford (2003) suggested a new genus for the cholo alethes and close relatives: Pseudoalethe based on mitochondrial and nuclear DNA sequence data. Based on those data the genus Alethe was polyphyletic, calling for the separation of Alethe castanea and Alethe diademata from other species of Alethe: Alethe poliocephala, Alethe fuelleborni, Alethe choloensis, and Alethe poliophrys. Currently, however, the Howard and Moore Checklist of Bird Species of the World (2003) only recognizes 5 species and retains them in the genus Alethe: Alethe diademata, Alethe poliophrys, Alethe poliocephala, Alethe fuelleborni, and Alethe choloensis. Alethe castanea is recognized as a subspecies: A. diademata castanea. Beresford (2003) suggested sister-species relationship between A. choloensis and A. fuelleborni. (Beresford, 2003; Dickinson, 2003)

Alethe choloensis is also known by the common names: Thyolo alethe and Cholo Mountain alethe. (BirdLife International, 2008)

Contributors

Tanya Dewey (author), Animal Diversity Web.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

References

Barnes, K., F. Dowsett-Lemaire, M. Dyer, J. Haugaard, P. Kaliba, L. Luhanga, V. Parker. 2009. "Species factsheet: Thyolo alethe (Alethe choloensis)" (On-line). BirdLife International. Accessed February 11, 2009 at http://www.birdlife.org/datazone/search/species_search.html?action=SpcHTMDetails.asp&sid=6456&m=0.

Beresford, P. 2003. Molecular systematics of Alethe, Sheppardia and some other African robins (Muscicapoidea). Ostrich, 74: 58-73.

BirdLife International, 2008. "Alethe choloensis" (On-line). IUCN Redlist of Endangered Species. Accessed February 10, 2009 at http://www.iucnredlist.org/details/147307.

Dickinson, E. 2003. The Howard and Moore Complete Checklist of the Birds of the World. Princeton: Princeton University Press.

Marshall Cavendish Corporation, 2001. Endangered Wildlife and Plants of the World. New York: Marshall Cavendish.

Seddon, N., J. Ekstrom, D. Capper, I. Isherwood, R. Muna, R. Pople, E. Tarimo, J. Timothy. 1999. The importance of the Nilo and Nguu North Forest Reserves for the conservation of montane forest birds in Tanzania. Biological Conservation, 87: 59-72.

Spottiswoode, C., I. Patel, E. Herrman, J. Timberlake, J. Bayliss. 2008. Threatened bird species on two little-known mountains (Chiperone and Mabu) in northern Mozambique. Ostrich, 79: 1-7.

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