An overlooked population of White-collared Oliveback Nesocharis ansorgei, in Angola Michael S. L. Millsa,b and Pedro Vaz Pintoc,d Uma população previamente desconhecida de asa-verde-de-colar-branco Nesocharis ansorgei em Angola. Aqui reportamos avistamentos de asa-verde-de-colar-branco Nesocharis ansorgei em três locais distintos no bloco norte das florestas de escarpa de Angola. Esta população anteriormente negligenciada está a mais de 1.500 km de distância da sua mancha de distribuição conhecida ao redor do Albertine Rift. Também demonstramos que, ao contrário do que consta em guias de campo, ambos os sexos possuem um colar branco, e de espessura uniforme ao longo da sua extensão. O livebacks Nesocharis are a genus of African finch comprising three species. Shelley’s Oliveback N. shelleyi is confined to highland forests and forest edge in south-east Nigeria, south-west Cameroon and the island of Bioko (Equatorial Guinea), whereas White-collared Oliveback N. ansorgei is endemic to montane forest edge and swamps in the Albertine Rift and surrounding areas of eastern Democratic Republic of Congo (DRC), Uganda, Rwanda, Burundi and north-west Tanzania. In both species the male has an olive breast, whereas the female has uniform grey underparts. The third species, Grey-headed Oliveback N. capistrata, occurs in mesic savannas north of the Guinea-Congo forest zone, from western Uganda to Guinea-Bissau. No species of oliveback has been recorded south of the Congo Basin (Fry & Keith 2004). On 29 August 2011 MSLM was leading a bird tour for Birding Africa, which had set up camp 7 km south of Quibaxi (08°30’22”S 14°34’59”E) in Kwanza Norte province, Angola, at 980 m altitude. Walking the edge of some nearby secondary forest, they encountered a party of four olivebacks perched in some vine tangles. This came as a great surprise since no oliveback species had previously been recorded in Angola (Dean 2000). Based on plumage characteristics noted at the time, they were either Shelley’s Oliveback, White-collared Oliveback or a new species. Only the female was seen well; white markings on the neck-sides were thought to be most similar to those in male Shelley’s Oliveback. Several weeks later, in September 2011, M. Lilje & D. Hoddinott, while leading a tour for Rockjumper Tours, found three olivebacks in secondary forest 10 km south-west of Quitexe (07°56’36”S 15°02’25”E) at c.790 m altitude, 64 – Bull ABC Vol 22 No 1 (2015) which they, unaware of the previous sighting, reported as a new species for Angola and perhaps as a new species to science (www.wildlifeextra.com/ go/news/oliveback-angola.html#cr; D. Hoddinott in Bull. ABC 19: 94). They noted that the birds most closely resembled White-collared Oliveback, although the tail appeared longer and the white collar extended onto the back of the neck, contrary to illustrations of this species in Stevenson & Fanshawe (2002) and Sinclair & Ryan (2010) (D. Hoddinott in litt. 2011). In October 2011 and August 2012 MSLM again observed these olivebacks at the first site, near Quibaxi, but on neither occasion was the observation sufficiently prolonged to enable a detailed study of the plumage. Then, on 27 September 2013, K. D. Dijkstra, unaware of the previous observations, reported a family of four olivebacks at forest edge near Uige town (07°36’44”S 14°57’48”E), just above 800 m, which he tentatively identified as White-collared Oliveback. Finally, on 21 May 2014, we returned to the original location near Quibaxi. This time we located a family of four olivebacks feeding in grass beside a track. We spent c.5 minutes observing them at close range and at different angles through a telescope, and PVP obtained a series of photographs (Figs. 1–6). Detailed study revealed that the white collars were of equal width around the entire head, although they could appear wider at the sides depending on how the head was held. Furthermore, both sexes possessed complete white collars. Based on information in Stevenson & Fanshawe (2002), Fry & Keith (2004) and Sinclair & Ryan (2010), these birds did not match any species of oliveback. A population of White-collared Oliveback in Angola: Mills & Vaz Pinto 1 2 4 3 5 Figures 1–6. Female White-collared Oliveback Nesocharis ansorgei, 7 km south of Quibaxi, Kwanza Norte province, Angola, 21 May 2014; note how the white collar is complete but appears broader in different sections depending on how the head is held (Pedro Vaz Pinto) Figuras 1–6. Fêmea de asa-verde-de-colar-branca Nesocharis ansorgei, 7 km a sul de Quibaxe, província do Kwanza-Norte, Angola, 21 de maio de 2014; de notar como o colar branco é completo mas aparece mais espesso em diferentes secções conforme a posição da cabeça (Pedro Vaz Pinto) 6 This led us to search the internet for photographs of White-collared Oliveback (e.g. Figs. 7–12). These demonstrate that, depending on the angle at which the head is held, the white collar can appear broader at the base or sides of the neck, and that both sexes possess a complete white collar. As most museum specimens are prepared with their heads pointing forward, this probably makes the white collar appear broader between the breast and head than elsewhere along its circumference (Fig. 13–14). This would explain the illustrations in Stevenson & Fanshawe (2002), Fry & Keith (2004) and Sinclair & Ryan (2010). The photographs also demonstrate that the pattern of the collar observed in the Angolan birds is well within the range displayed in Whitecollared Oliveback. We therefore present these observations and photographs as the first records of White-collared Oliveback in Angola, a species known previously only from >1,500 km away in eastern DRC. The three Angolan localities at which the species has been recorded are located at 790–980 m altitude, suggesting that the species may be comparatively widespread over the northern escarpment zone in secondary forest and forest edge, i.e. similar habitats to East Africa, albeit at slightly lower altitudes (Fry & Keith 2004). The only other species to show a similar, disjunct distribution is Dusky Twinspot Euschistospiza cinereovinacea, which is represented A population of White-collared Oliveback in Angola: Mills & Vaz Pinto Bull ABC Vol 22 No 1 (2015) – 65 7 8 10 9 11 12 Figures 7–12. White-collared Olivebacks Nesocharis ansorgei photographed in Uganda and Rwanda; note the complete white collar in both sexes and how variable the thickness of the collar appears between the breast and the head depending on how the latter is held (Fig. 7: Jonas Rosquist; Figs. 8–9: Adam Scott Kennedy; Figs. 10–12: Jason Anderson) Figuras 7–12. Asas-verde-de-colar-branco Nesocharis ansorgei, fotografados no Uganda e Rwanda; de notar o colar branco completo em ambos os sexos e como parece variável a espessura do colar entre o peito e a cabeça, dependendo de como esta última se posiciona (Fig. 7: Jonas Rosquist; Figs. 8–9: Adam Scott Kennedy; Figs. 10–12: Jason Anderson) 66 – Bull ABC Vol 22 No 1 (2015) A population of White-collared Oliveback in Angola: Mills & Vaz Pinto by endemic E. c. cinereovinacea in Angola and E. c. graueri in the Albertine Rift. Acknowledgements Many thanks to David Hoddinott and K. D. Dijkstra for sharing details of their observations with us. Mike Rogerson, Chris Hines and Nito Rocha accompanied us during field trips. Jonas Rosquist, Adam Scott Kennedy and Jason Anderson kindly granted permission for their photographs to be published in conjunction with this note. 13 References 14 Figures 13–14. Male Shelley’s Oliveback Nesocharis shelleyi (above) and White-collared Oliveback N. ansorgei (below) specimens; note how much broader the white collar appears above the breast of the latter species, compared to along the rest of its circumference (© Natural History Museum, London) Figuras 13–14. Exemplares de macho de asaverde-de-Shelley Nesocharis shelleyi (em cima) e de asa-verde-de-colar-branco N. ansorgei (em baixo); de notar o quão mais largo é o colar branco acima do peito na última espécie, comparado com a sua aparência ao redor da circunferência (© Natural History Museum, London) Dean, W. R. J. 2000. The Birds of Angola: An Annotated Checklist. BOU Checklist No. 18. Tring: British Ornithologists’ Union. Fry, C. H. & Keith, S. (eds.) 2004. The Birds of Africa. Vol. 7. London, UK: Christopher Helm. Sinclair, I. & Ryan, P. 2010. Birds of Africa South of the Sahara. Second edn. Cape Town: Struik. Stevenson, T. & Fanshawe, J. 2002. Field Guide to the Birds of East Africa. London, UK: T. & A. D. Poyser. a A. P. Leventis Ornithological Research Institute, University of Jos, PO Box 13404, Jos, Plateau State, Nigeria. E-mail: michael@birdingafrica.com b DST/NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch 7701, South Africa. c Instituto Superior de Ciências da Educação da Huíla, Lubango, Angola. d Fundação Kissama, Luanda, Angola. Received 13 July 2014; revision accepted 26 October 2014. A population of White-collared Oliveback in Angola: Mills & Vaz Pinto Bull ABC Vol 22 No 1 (2015) – 67