|Male (above) and female (below) on Sal|
The Iago sparrow (Passer iagoensis) is a passerine bird of the sparrow family Passeridae, also known as the Cape Verde sparrow or the rufous-backed sparrow. It is endemic to the Cape Verde Islands, in the eastern Atlantic Ocean near western Africa; there, it occurs on all but one island, and is numerous on most. Females and young birds have brown plumage with black marks above, and a dull grey underside, and are distinguished from other species of sparrow by their large, distinct supercilium. Males have a brighter underside and bold black and chestnut stripes on their head. At 12.5–13 centimetres (4.9–5.1 in) long, it is a smaller sparrow. Vocalisations are mostly variations on its chirp, which differ somewhat between males and females.
The Iago sparrow is a small sparrow, 12.5–13 centimetres (4.9–5.1 in) long, with a wing length of 5.5–6.9 centimetres (2.2–2.7 in). Its plumage is similar to that of the house sparrow, and it similarly is sexually dimorphic. The male has a black or greyish-black crown and eyestripe, a grey nape and a small patch of white on the lower forehead. The sides of its head, especially above the eye, are a rich cinnamon colour. The scapulars are white and brown, while the rest of the upperparts are brown, streaked with black and beige. The cheeks and underparts are pale grey, and the throat and chin are marked with a small black bib. The female is grey-brown, with black-streaked wings and breast, and pale grey underparts. It is very similar to the female house sparrow but has a more apparent pale supercilium (stripe over the eye). The juvenile resembles the adult female, but young males are more chestnut from an early age, with a trace of a black bib on the chin. In 1898, British ornithologist Boyd Alexander reported that adults begin moulting in early February, and some birds were still in moult by late May.
The Iago sparrow's vocalisations include calls, varying between the sexes, elaborations of these called 'songs', and an alarm call. Calls are chirps, somewhat similar to those of other sparrows, the usual version made by males described as a "twangy" cheesp or chew-weep, and that of females described as a "more sibilant" chisk. The song is a long, elaborated series of call notes, and is made by breeding males in their nests. An alarm call like that of other sparrows, transcribed chur-chur-chur, is also used.
The Iago sparrow was first collected by Charles Darwin during the first stop of the second voyage of HMS Beagle at Santiago island. It was described for him in 1837 by zoologist John Gould, in the Proceedings of the Zoological Society of London, and given the name of Pyrgita iagoensis. By the time Gould wrote The Zoology of the Voyage of H.M.S. Beagle with Darwin and three other zoologists in 1841, he had placed the Iago sparrow in the genus Passer, in which it has since been placed. The genus, among the sparrows of the Old World in the family Passeridae, also contains at least 20 other species, among them the house sparrow and Eurasian tree sparrow.
Within its genus, the Iago sparrow has been considered one of the African 'rufous sparrows', a group which also includes species such as the great sparrow (Passer motitensis). These birds were usually treated as distinct species until Reginald Ernest Moreau, writing in the 1962 Check-list of the Birds of the World, lumped the Iago sparrow and the mainland rufous sparrows as the single species Passer motitensis. This taxonomy was followed frequently until J. Denis Summers-Smith, a world authority on sparrows, argued in the 1980s that the Iago sparrow's many differences in morphology and behaviour, and separation from the other rufous sparrows by about 5,000 kilometres (3,100 mi), are sufficient grounds for species status. Studies of mitochondrial and nuclear DNA further suggest it may be a close relative of the house sparrow and the Spanish sparrow, rather than the rufous sparrows.
French ornithologist Émile Oustalet described a specimen from Branco as a separate species Passer brancoensis in 1883, which was recognised as a subspecies recognised by W. R. P. Bourne, who claimed to observe differences between birds from different islands. According to Bourne, birds of Passer iagoensis iagoensis on more wooded islands in the south are darker and larger, and also behave more like house or Spanish sparrows, competing with them better in human-altered habitats. He later wrote that the variations he saw comprised two clinal trends, of increasing darkness towards the south, and of smaller size further from the continental coast. Charles Vaurie, examining differences in plumage and measurements of specimens in major museums, did not find any significant variation, and neither Vaurie nor Summers-Smith recognised any subspecies.
Distribution and habitat
The Iago sparrow is endemic to the Cape Verde Islands. It is common on most islands, excluding Fogo (from which it is absent) and Santa Luzia, Branco and Sal (on which it is scarce). It can be found in a variety of habitats, including flat lava plains, cliffs, gorges, and edges of farmland, at altitudes of up to 1,200 metres (3,900 ft). It has also been seen in urban areas and gardens on islands, where it occurs alongside the house sparrow, but not the Spanish sparrow. In agricultural areas the bird may do some damage to crops, mostly by eating buds and shoots. The Iago sparrow is highly common in its limited range, though its exact population is not known. Though it may be at risk to unpredicted changes in its environment, due to its limited range, it is assessed as Least Concern by the IUCN Red List.
In May 2013 four Iago sparrows were found on board the ship Plancius as it docked at Hansweert, in the Netherlands. The birds were thought to have flown onto the ship as it passed the island of Raso.
The Iago sparrow is gregarious, usually breeding in small colonies, and forming large flocks outside the breeding season. It is not shy, allowing humans to approach it even at its nest. It is attracted to water, which is scarce in its habitat. It often is seen dust bathing in small groups.
The adult sparrow feeds mainly on seeds, but also on insects and shoots. Nestlings, by contrast, feeds almost exclusively on insects. It forages mostly on the ground, moving restlessly and close to the ground. It flocks with other birds, even warblers such as the blackcap and the Cape Verde warbler.
This sparrow's breeding habits are not well known, though they are believed to be similar to those of the house sparrow. Its breeding season begins in August and September with the onset of the humid season. The Iago sparrow builds its nest in a variety of habitats, including lava plains, cliffs, and gardens. The nest is made of grass, lined with hair and feathers and usually built in a hole in a cliff or wall. The average clutch is three to five eggs.
- BirdLife International (2012). "Passer iagoensis". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- "Description et Énumération des Espèces". Actes de la Société Linnéenne de Bordeaux (in French) 38. 1883.
- Summers-Smith 1988, pp. 93–95
- Clement, Harris & Davis 1993, pp. 455–456
- Gould 1838, p. 95
- Alexander, Boyd (1898). "An Ornithological Expedition to the Cape Verde Islands". The Ibis. 7 4: 74–118.
- Summers-Smith 1988, p. 100
- Gould, J. (1837). "Exhibition of Mr. Darwin's Birds, and description of a New Species of Wagtail (Motacilla leucopsis) from India". Proceedings of the Zoological Society of London V: 77–78.
- Summers-Smith, J. Denis (2009). "Family Passeridae (Old World Sparrows)". In del Hoyo, Josep; Elliott, Andrew; Christie, David. Handbook of the Birds of the World. Volume 14: Bush-shrikes to Old World Sparrows. Barcelona: Lynx Edicions. ISBN 978-84-96553-50-7.
- Summers-Smith, D. (1984). "The Rufous Sparrows of the Cape Verde Islands". Bulletin of the British Ornithologists' Club 104 (4): 138–141.
- González, Javier; Siow, Melanie; Garcia-del-Rey, Eduardo; Delgado, Guillermo; and Wink, Michael (2008). "Phylogenetic relationships of the Cape Verde Sparrow based on mitochondrial and nuclear DNA" (PDF). Systematics 2008, Göttingen. Archived from the original on 22 July 2011.
- Bourne, W. R. P. (1955). "The Birds of the Cape Verde Islands". Ibis 97 (3): 508–556. doi:10.1111/j.1474-919X.1955.tb04981.x.
- Bourne, W. R. P. (1957). "Additional Notes on the Birds of the Cape Verde Islands, with Particular Reference to Bulweria mollis and Fregata magnificens". Ibis 99 (2): 182–190. doi:10.1111/j.1474-919X.1957.tb01945.x.
- Vaurie, C. (1958). "The Rufous-backed Sparrows Passer iagoensis of the Cape Verde Islands". Ibis 100 (2): 275–276. doi:10.1111/j.1474-919X.1958.tb08798.x.
- "Kaapverdische Mus – Passer iagoensis (Gould, 1838)". Waarneming.nl (in Dutch). Stichting Natuurinformatie.
- Summers-Smith 1988, pp. 98–100
- Alexander, Boyd (1898). "Further Notes on the Ornithology of the Cape Verde Islands". The Ibis. 7 4: 277–285.
- Donald, P. F.; Taylor, R.; de Ponte Machado, M.; Pitta Groz, M. J.; Wells, C. E.; Marlow, T.; Hille, S. M. (2004). "Status of the Cape Verde Cane Warbler Acrocephalus brevipennis on São Nicolau, with notes on song, breeding behaviour and threats" (PDF). Malimbus 26: 34–37.
- Works cited
- Clarke, Tony; Orgill, Chris; Dudley, Tony (2006). A Field Guide to the Birds of the Atlantic Islands. London: Christopher Helm. ISBN 0-7136-6023-6.
- Clement, Peter; Harris, Alan; Davis, John (1993). Finches and Sparrows: an Identification Guide. Princeton, New Jersey: Princeton University Press. ISBN 0-691-03424-9.
- Gould, John (1838). Darwin, Charles, ed. The Zoology of the H.M.S. Beagle, under the command of Captain Robert Fitzroy, R. N., during the years 1832 to 1836. Part III: Birds. London: Smith, Elder, and Company.
- Snow, D. W.; Perrins, C. M. (1998). The Birds of the Western Palearctic 2 (Concise ed.). Oxford: Oxford University Press. ISBN 0-19-854099-X.
- Summers-Smith, J. Denis (1988). The Sparrows. illustrated by Robert Gillmor. Calton, Staffs, England: T. & A. D. Poyser. ISBN 0-85661-048-8.
- Williamson, M.H. (1996). Technology in the Third Millennium. Volume 15: Biological Invasions. Springer. ISBN 978-0-412-59190-7.