Dwarf Bittern Ixobrychus sturmii Scientific name definitions

25–30 cm (1 Borrow, N., and R. Demey (2001). Birds of Western Africa. Christopher Helm, London, UK. Close ); 142 g (one immature male) (2 Britton, P. L. (1970). Some non-passerine bird weights from East Africa. Bulletin of the British Ornithologists’ Club 90(5):142–144; 90(6):152–144. Close ); wingspan 50 cm (3 Clarke, T. (2006). Birds of the Atlantic Islands. Christopher Helm, London, UK. Close ). Distinguished from Butorides striata by smaller size, slower flight, pale and heavily streaked underparts, and uniform (not barred) upperparts, and from I. minutus by being darker, smaller and lacking pale wing-covert patches. Male has dark slate-grey head and neck , with elongated feathers, as well as upperparts and wings, pale buff throat  and upper breast, becoming tawny over abdomen, heavily streaked black; bill dark over maxilla with yellow mandible, lores and orbital skin  blue to yellow-green, eyes red-brown to dark red, and legs and feet green-yellow in front and yellow behind, turning bright red in courtship. Plumage variations very poorly known, but female paler, more rufous on belly . Juvenile more extensively buff and duller; upperparts tipped with buff, with yellow-grey bill, orange-red irides and yellow legs and feet.

Sub-Saharan Africa from Senegal to Ethiopia and S (avoiding arid zones) to South Africa.

Wooded areas or bush with dense foliage along margins of freshwater rivers, streams, lakes and pools; also marshes with grass  or reeds, seasonally flooded areas, mangroves, rice fields and swamps with grass, cattails or papyrus. Recorded to 1700 m in Zambia (4 Dowsett, R. J., D. R. Aspinwall, and F. Dowsett-Lemaire (2008). The Birds of Zambia. Tauraco Press & Aves, Liège, Belgium. Close ).

African migrant, movements related with changes in water level due to seasonal rains. Equatorial populations probably sedentary, numbers boosted by arrival of migrants from N or S, e.g. considered to be locally resident in Uganda (5 Carswell, M., D. Pomeroy, J. Reynolds, and H. Tushabe (2005). The Bird Atlas of Uganda. British Ornithologists’ Club and British Ornithologists' Union, Oxford, UK. Close ). Birds of southern third of Africa present Oct–Apr, presumably moving to equatorial zone during dry season, e.g. present in Zambia almost entirely between 11 Oct and 28 May (but occasionally Jun to mid Sept) (4 Dowsett, R. J., D. R. Aspinwall, and F. Dowsett-Lemaire (2008). The Birds of Zambia. Tauraco Press & Aves, Liège, Belgium. Close ), and in Malawi mainly recorded Nov–Apr, with few records at other times (6 Dowsett-Lemaire, F., and R. J. Dowsett (2006). The Birds of Malawi: An Atlas and Handbook. Tauraco Press & Aves, Liège, Belgium. Close ); in South Africa erratic seasonal movements in Nyl floodplains only when they are totally flooded, roughly Jan–Jun. Apparently present in extreme N of range only or mainly during rains, May–Sept, occasionally as late as Dec in S Somalia (7 Ash, J. S., and J. E. Miskell (1998). Birds of Somalia. Pica Press, Robertsbridge, UK. Close ) and as early as Mar in Ethiopia, where perhaps breeds (8 Ash, J. S., and J. Atkins (2009). Birds of Ethiopia and Eritrea: An Atlas of Distribution. Christopher Helm, London, UK. Close ). Recorded far outside usual range in Oman (Nov 2013) (9 Harrison, I. (2015). From the rarities committees. Sandgrouse 37(1):102–107. Close ), Cape Verde Is (Santiago, Jun–Jul 2011) (10 Hazevoet, C.J. (2012). Seventh report on birds from the Cape Verde Islands, including records of nine taxa new to the archipelago. Zool. Caboverdiana 3(1): 1–28. Close ), Canary Is (Tenerife, 1889 or 1890 and 1970s; Gran Canaria, Jan 2000; Tenerife, Aug 2002 to 2003, Fuerteventura, Nov 2017 into 2018) (11 de Juana, E. and el Comité de Rarezas de la Sociedad Española de Ornitología (2002). Observaciones de aves raras en España. Ardeola. 49(1): 141–171. Close , 12 Velmala, W., Clarke, T., Lindroos, R. and Nikkinen, L. (2002). A Dwarf Bittern on the Canary Islands – the fourth Western Palearctic record. Birding World. 15(9): 392–393. Close , 13 de Juana, E. and el Comité de Rarezas de la Sociedad Española de Ornitología (2004). Observaciones de aves raras en España, 2002. Ardeola. 51(2): 515–541. Close , 14 Kratzer, D., Lundy, V. and Ławicki, Ł. (2018). Two Dwarf Bitterns on Fuerteventura, Canary Islands, in winter of 2017/18. Dutch Birding. 40(2): 98–101. Close ), St Helena (Oct 2011–Jan 2012) (15 Hillman, J.C. and Clingham, E. (2012). First record of Dwarf Bittern Ixobrychus sturmii for St. Helena, South Atlantic. Bull. Afr. Bird Club. 19(2): 213–214. Close ) and Malta (Nov 2010) (16 Pitches, A. (2011). News & Comment: First record of Dwarf Bittern in Malta. British Birds. 104(8): 469. Close ), and surprisingly in France (mid-19th century), the latter a bird of doubtful origin.

Insects, including water beetles and especially grasshoppers, and frogs; also small fish, crabs, spiders and snails, with local specializations, e.g. on grasshoppers (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Feeds alone or in pairs, by Standing or Walking Slowly, and probably defends feeding territory (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); mainly nocturnal but also forages by day, especially in cloudy conditions.

In advertisement gives a “hoo, hoo, hoo” and a loud croak when disturbed (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ).

Season very variable, generally coinciding with rains, but sometimes early in dry season: Sept in Senegal (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); Aug–Oct in Mali (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); Jul in Ghana and Sierra Leone (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); Apr in Ethiopia; May–Jun in coastal Kenya; Dec–Jan in Zambia (4 Dowsett, R. J., D. R. Aspinwall, and F. Dowsett-Lemaire (2008). The Birds of Zambia. Tauraco Press & Aves, Liège, Belgium. Close ); Jan–Mar and Sept–Oct in Zimbabwe; Feb–Mar in Namibia (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); and Dec–Mar in Transvaal, South Africa. Solitary, occasionally in small groups of few dozen pairs and sometimes in loose association with Ardeola ralloides and A. rufiventris (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Nests in trees or bushes (e.g. Combretum, Ziziphus, Terminalia, Diospiros) (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ) on horizontal or hanging branches, occasionally in reeds (4 Dowsett, R. J., D. R. Aspinwall, and F. Dowsett-Lemaire (2008). The Birds of Zambia. Tauraco Press & Aves, Liège, Belgium. Close ), c. 0·5–4 m above water; nest is flimsy stick platform lined with dry grass, 230–380 mm in diameter and 70 mm deep (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Normally 3–4 white or faintly bluish eggs (2–5), size 33–40 mm × 26–29 mm, mass 19–20 g (18 Brown, L. H., E. K. Urban, and K. Newman (1982). The Birds of Africa. Volume 1. Academic Press, London, UK and New York, USA. Close ); incubation 18+ days, perhaps commencing with last egg (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); chicks apparently hatch synchronously and have ginger-brown down, with dark brown eyes and rest of bare parts pinkish (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); wander from nest at c. 1 week; remiges start to appear at 11 days. One study found that c. 69% of eggs hatched (17 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ).

Not globally threatened (Least Concern). Widespread, but uncommon to rare throughout extensive range. Locally common during breeding, e.g. in NE Namibia, S Angola. In Malawi, where still much suitable habitat for the species, known from protected areas such as Liwonde and Lengwe National Parks (6 Dowsett-Lemaire, F., and R. J. Dowsett (2006). The Birds of Malawi: An Atlas and Handbook. Tauraco Press & Aves, Liège, Belgium. Close ). Population of South Africa estimated at c. 200 pairs in wet season; no evidence of decrease. Only recently confirmed to occur in Guinea-Bissau, where just two records (Feb 1997 and Jul 2011), despite being known from all neighbouring countries (19 Guilherme, J.L. (2014). Birds of the Boé region, south-east Guinea-Bissau, including the first country records of Chestnut-backed Sparrow Lark Eremopterix leucotis, Lesser Striped Swallow Cecropis abyssinica and Heuglin’s Wheatear Oenanthe heuglini. Bull. Afr. Bird Club. 21(2): 155–168. Close ).