Swynnerton's robins are known from a few mountain ranges in eastern Zimbabwe, Mozambique, and Tanzania. There are two, sometimes three, recognized subspecies, each occurring on different mountain ranges. Swynnertonia swynnertoni swynnertoni occurs on Chirinda mountain in Zimbabwe and a few smaller mountains bordering Mozambique, including Mt. Gorongosa. Swynnertonia swynnertoni rodgersi occurs in Tanzania in the Udzungwa and East Usambara Mountains. Swynnerton's robins were recently discovered in a pristine forest fragment on Mt. Mabu in Mozambique, documenting their existence in a previously unrecognized portion of their range. (BirdLife International, 2008a; BirdLife International, 2008b; Collar, 2005; Vickers, 2009)
Swynnerton's robins are found primarily in tropical montane forests, from 850 to 1800 m elevation, more common at 900 to 1200 m. The population in the East Usambaras Mountains occurs in lowland evergreen forest, from 130 to 550 m elevation. Some populations seem to be associated with a dominant understory plant: Dracaena fragrans. They are typically seen in the forest understory or on the ground, in contrast to Pogonocichla species that co-occur. Swynnerton's robins are generally restricted to forest interiors, typically near streams or seeps. They seem to prefer forests with closed canopies and open understory structure, with plenty of leaf litter on the ground. (BirdLife International, 2008a; Collar, 2005)
- Range elevation
- 130 to 1800 m
- 426.51 to 5905.51 ft
Swynnerton's robins are 12 to 13 cm in length, with blue-grey plumage dorsally and a bright orange breast. The orange plumage of the breast becomes lighter on the belly, becoming a buffy yellow and then white at the vent. The head and chin are grey and there is a small white bib bordered by a black line that separates it from the orange of the breast. They have long legs and feet with grayish flesh-colored skin. The feathers on the wing have an olive-green cast to them. The bill is black and there is a light, indistinct white circle around the eyes which is more prominent above the eye. Swynnerton's robins look much like New World robins (Turdus) in overall appearance and habits, they are generally seen foraging on the ground. They hold their tail at a characteristic 45 degree angle. Females are similar to males, but with more olive on the head and lighter cheeks. Juveniles are brown with yellow spotting above and with a lighter orange breast and belly. Subspecies vary somewhat in coloration. (BirdLife International, 2008b; Collar, 2005)
- Sexual Dimorphism
- sexes colored or patterned differently
- Range length
- 12 to 13 cm
- 4.72 to 5.12 in
There is no information on the mating system of Swynnerton's robins. They are generally observed in pairs, so may be monogamous. (BirdLife International, 2008b)
Swynnerton's robins breed from October to January, with generally two clutches each breeding season. Breeding peaks from November to December. Nests are constructed over the course of 7 to 10 days. Nests are cup-shaped, with a wide rim, and constructed of various plant materials and lined with finer fibers. Nests are typically placed 0.3 to 2 meters above ground, often in Dracaena fragrans axils or at the base of a branch. Eggs are shiny and blue-green with brown spots and blotches. Females lay 2, sometimes 3 eggs and begin to incubate with the first egg. Incubation is complete at 15 to 16 days and young fledge within 14 days after hatching. (BirdLife International, 2008a; Collar, 2005)
- Key Reproductive Features
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- Breeding interval
- Swynnerton's robins lay two clutches each year in the breeding season.
- Breeding season
- Swynnerton's robins breed from October to January.
- Range time to hatching
- 15 to 16 days
- Average fledging age
- 14 days
Like most Passeriformes, Swynnerton's robins young are likely to hatch in an altricial state and require significant parental investment to survive to fledging. However, there is no specific information on parental care available in the literature.
- Parental Investment
Longevity of Swynnerton's robins in the wild or captivity is not known.
Swynnerton's robins are active during the day. They do not migrate. There are no reports that indicate how territorial or social these birds are outside of the breeding season. They are common within suitable forest fragments. (Collar, 2005)
Home range sizes are not reported in the literature. Population densities of 75 individuals per square kilometer are reported from secondary forest. In primary forest 4 to 6 pairs per hectare have been reported. (Collar, 2005)
Communication and Perception
Swynnerton's robins use several vocalizations: a "loud song," "warbling song," and several alarm calls. Songs vary slightly across their range. The loud song is characterized as a sweet, whistling phrase: "cha-chii-roo" or "tee ter-wer choo." The warbling song is a soft and musical whistle and is generally heard near ant swarms. When alarmed, these robins use a descending trill call that ends in several raspy squeaks, "trrrrr-wii-twaw-twiii," or a short "siiip." (Collar, 2005)
- Communication Channels
Swynnerton's robins eat mainly insects. They hunt for insects on the forest floor by tossing aside leaf litter and opportunistically taking what they find. They also accompany army ant swarms and take the insects that are fleeing. Insect prey are diverse, including beetles, ants, wasps, moths, caterpillars, bugs, spiders, flies, and others. They have also been recorded eating small forest frogs (Arthroleptis xenodactyloides) and some fruits. (Collar, 2005)
- Animal Foods
- terrestrial non-insect arthropods
- Plant Foods
Predation on Swynnerton's robins is not reported in the literature. It is likely that eggs and nestlings are preyed on by small, terrestrial carnivores and snakes and that adults may be taken by small birds of prey or owls.
Swynnerton's robin nests are sometimes parasitized by red-chested cuckoos (Cuculus solitarius).
- red-chested cuckoos (Cuculus solitarius)
Economic Importance for Humans: Positive
Swynnerton's robins are restricted to native forest fragments and may act as indicators of habitat quality. Because of their rarity, they may attract ecotourism interest.
- Positive Impacts
Economic Importance for Humans: Negative
There are no known adverse effects of Swynnerton's robins on humans.
Swynnerton's robins have a small range that is highly fragmented and populations are declining. Throughout most of their range they are threatened by forest destruction and degradation resulting from resource extraction. In the East Usambaras it is possible that adventure tourism is threatening local populations and in Zimbabwe forest degradation is resulting from the spread of a non-native ginger, Hedychium. Some populations are found primarily in protected areas, although enforcement of forest protection may be incomplete in some areas. The global population is estimated at from 2500 to 9999 individuals. (BirdLife International, 2008a)
Tanya Dewey (author), Animal Diversity Web.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
uses sound to communicate
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.
- 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.
an animal that mainly eats meat
uses smells or other chemicals to communicate
- active during the day, 2. lasting for one day.
humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.
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 biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly insects or spiders.
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).
having the capacity to move from one place to another.
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.
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
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sight to communicate
Beresford, P. 2003. Molecular systematics of Alethe, Sheppardia and some other African robins (Muscicapoidea). Ostrich, 74: 58-73.
Biodiversity Explorer, 2008. "Swynnertonia swynnertoni (Swynnerton's robin)" (On-line). Biodiversity explorer: the web of life in Southern Africa. Accessed February 10, 2009 at http://www.biodiversityexplorer.org/birds/muscicapidae/swynnertonia_swynnertoni.htm.
BirdLife International, 2008. "Species factsheet: Swynnertonia swynnertoni" (On-line). BirdLife International. Accessed February 18, 2009 at http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=6577&m=0.
BirdLife International, 2008. "Swynnertonia swynnertoni" (On-line). IUCN Redlist of Endangered Species. Accessed February 06, 2009 at http://www.iucnredlist.org/details/147426.
Collar, N. 2005. Family Turdidae (Thrushes). Pp. 514-807 in J del Hoyo, A Elliott, D Christie, eds. Handbook of the Birds of the World, Vol. 10. Barcelona: Lynx Edicions.
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.
Vickers, H. 2009. "Google earth reveals hidden oasis" (On-line). BirdLife International. Accessed February 06, 2009 at http://www.birdlife.org/news/news/2009/01/mount_mabu.html.