African stonechat

African stonechat
Adult male in South Africa
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Subclass: Neornithes
Infraclass: Neognathae
Superorder: Neoaves
Order: Passeriformes
Suborder: Passeri
Infraorder: Passerida
Superfamily: Muscicapoidea
Family: Muscicapidae
Genus: Saxicola
Species: S. torquatus
Binomial name
Saxicola torquatus
(Linnaeus, 1766)
Diversity
13-17 subspecies
Synonyms

Pratincola pallidigula Reichenow, 1892
Saxicola axillaris (Shelley, 1884)
Saxicola torquata (lapsus)

Eggs, Collection Museum Wiesbaden, Germany
Adult male S. t. axillaris from Kenya

The African stonechat or common stonechat[2] (Saxicola torquatus) is a species of the Old World flycatcher family (Muscicapidae), inhabiting sub-Saharan Africa and adjacent regions. Like the other chats, it was long assigned to the thrush family (Turdidae), to which the chats are convergent. Its scientific name refer to its appearance and habitat and means "collared rock-dweller": Saxicola from Latin saxum ("rock") + incola ("one who dwells in a place"), torquatus, Latin for "collared".

In the past S. torquatus usually referred to the entire "common stonechat" superspecies and some sources[3] still keep it that way, but all available evidence strongly supports full species status for the European (S. rubicola) and the Siberian stonechat (S. maurus) of temperate Eurasia, in addition to the island-endemics Fuerteventura chat (S. dacotiae) and Réunion stonechat (S. tectes) which were never unequivocally accepted into S. torquata. The Madagascan stonechat is also considered distinct. In addition, the well-marked populations of the Horn of Africa uplands may well qualify for an additional species.[4]

Systematics and taxonomy

The closest relative of this species are apparently not the Eurasian populations but the Réunion stonechat (S. tectes), but still the "white-collared" Saxicola form a distinct group in the genus. S. torquatus and S. tectes form a sub-Saharan African lineage that diverged from the Eurasian one in the Late Pliocene, roughly 2.5 million years ago. Réunion was colonized shortly thereafter, indicating a rapid expansion along the Indian Ocean coast of Africa. With the Sahara drying out in the subsequent Quaternary glaciation, the African and Eurasian populations became isolated for good.[5]

The recent separation as species was proposed after mtDNA cytochrome b sequence and nDNA microsatellite fingerprinting analysis of specimens of the subspecies Saxicola torquatus axillaris but not S. t. torquatus, and hence this species was briefly known as S. axillaris.[5]

Subspecies

The subspecies differ slightly in size, and more in the extent of the orange-red on the upper breast of the males, and whether the lower breast is white with a distinct boundary from the upper breast, or pale orange with an indistinct boundary from the darker upper breast. The extent of the orange-red also varies with time of year, often extending on to the belly outside the breeding season.[6]

Upper breast black, not orange-red.
The largest subspecies. Length of flattened wing c.75-78 mm (3 in).[7]
Mid-sized, length of flattened wing c.70 mm (c.2.7 in).[7]
Very limited orange-red on uppermost part of breast only.
Extensive orange-red on breast and also flanks.
The smallest subspecies.
Previously included within promiscua, and very similar to it.

Description

The males have a black head, a white half-collar, a black back, a white rump, and a black tail; the wings are black with a large white patch on the top side of the inner wing. The upper breast is usually dark orange-red, with a sharp or gradual transition to white or pale orange on the lower breast and belly depending on subspecies. In a few, black replaces the orange breast feathers in part or entirely.[6]

Females have brown rather than black above and on the head with an indistinct paler eyebrow line, chestnut-buff rather than orange below, and less white on the wings. Both sexes' plumage is somewhat duller and streakier outside the breeding season.[6]

Distribution and habitat

It has a scattered distribution across much of sub-Saharan Africa, occurring locally as far north as Senegal and Ethiopia. Outlying populations are found the mountains of southwest Arabia and on Madagascar and Grande Comore. It is non-migratory, moving only locally if at all. As a result, it has developed much regional variation, being divided into about 15 subspecies.[6]

Footnotes

  1. ↑ BirdLife International (2012). "Saxicola torquatus". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
  2. ↑ Common Stonechat (Saxicola torquatus), Internet Bird Collection
  3. ↑ E.g. BLI (2008)
  4. ↑ Wittmann et al. (1995), Urquhart & Bowley (2002), Wink et al. (2002), Woog et al. (2008)
  5. 1 2 Wink et al. (2002)
  6. 1 2 3 4 Urquhart & Bowley (2002)
  7. 1 2 Boulton & Rand (1952)

References

External links

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