Ornithology Department
 
 

Scientific articles

 

 

De Swardt DH 2017. Birds of the Bloemfontein pentad 2905_2610: a review over a 30 year period. Biodiversity Observations, Vol 8.43: 1-17

De Swardt, D. H. 2017. The call note - A new vocalization for the African Rock Pipit Anthus crenatus. Biological Observations 8. 10: 1-3.

De Swardt, D. H. 2017. Living in isolation - Observations on African Rock Pipits in the Northern Cape. Biological Observations 8. 13: 1 - 6.

Oatley, G., De Swardt, D. H., Nuttall, R. J., Crowe, T. M. & Bowie, R. C. K. 2017. Phenotypic and genotypic variation across a stable white-eye (Zosterops sp.) hybrid zone in central South Africa. Biological Journal of the Linnean Society 121: 670-684. 

De Swardt, D. H., Mashao, M. & Engelbrecht, G. D. 2016. Diet of the Pririt Batis Batis pririt in the Free State, South Africa. Biodiversity Observations 7 .67: 1-2.

De Swardt, D. H. 2016.White-crested Helmet-shrike in the Vredefort area, Northern Free State. Biological Observations 7.4: 1-2.

De Swardt, D. H. 2016.Alarm calls of African Rock Pipit Anthus crenatus – A new vocalization. Biological Observations 7.17: 1-3.

De Swardt, D. H. 2016.Birds ringed and recaptured at Kalkwal, Free State. Biodiversity Observations 7: 23: 1 - 4.

De Swardt, D. H. 2016. Secretarybird Sagittaruis serpentaruis resighted after 5 years. Biodiversity Observations 7: 26: 1 - 2.

De Swardt DH 2016.Feral population of Common Peacock Pavo cristatus breeding in Boemfontein, Free State. Biodiversity Observations 7.56: 1-2.

De Swardt DH 2016.Lesser Grey Shrike and Common Fiscal impaling prey. Biodiversity Observations 7.57: 1-2.

De Swardt DH 2016.Observations on a Secretarybird nest at Langfontein, Petrusburg district, Free State. Biodiversity Observations 7.64:1-4.

Retief, E. F., Smith-Robinson, H. A. & De Swardt, D. H. 2015.Egyptian Geese nesting in Secretarybird nests. Ornithological Observations 6: 215 - 216.

De Swardt, D. H. & van der Westhuizen, A. C. 2015. Secretarybird Sagittarius serpentarius ringing in the Free State and Eastern Cape: movement data on patagial-tagged nestlings. Gabar 26: 8 – 10.

De Swardt, D. H. 2015. Observations of African Jacanas at Rooidam, Bloemfontein. Ornithological Observations 6: 202 – 204.

Mashao, M, Engelbrecht, D. & de Swardt, D. H. 2015. Desktop ecology: Sabota Lark Calendulauda sabotaOrnithological Observations 6: 84 – 91.

De Swardt, D. H. & Boshoff, W. 2015. Golden-tailed Woodpeckers along Orange River in southern Free State. Ornithological Observations 6: 29 - 30.

De Swardt, D. H. 2014. Bird distribution changes in the Lydenburg area, Mpumalanga (2530AB Lydenburg & 2530BA Long Tom Pass) using SABAP data to compare with historical data: a period since the 1980’s. Ornithological Observations 5: 431 - 449.

De Swardt, D. H. 2014. Spotted Eagle-owl nesting on top of Sociable Weaver nest.Ornithological Observations 5: 355 – 356.

De Swardt, D. H. 2014. A comparative analysis of SABAP2 data for the Free State National Botanical Gardens and the Valley of Seven Dams Conservancy, Bloemfontein.Ornithological Observations 5: 1 – 8.

De Swardt, D. H. 2014. Recapture and movement data of Gurney’s Sugarbird Promerops gurneyi in the Lydenburg area, Mpumalanga Province, over nearly three decades.Afring News 43: 3 – 8.

De Swardt, D. H. 2014. An unconvenient death: Eastern Clapper Lark on barbed wire fence.Ornithological Observations 5: 112 - 113.

De Swardt, D. H. 2013. Unusual golden colour variation of Green-winged Pytilia ringed at Dedeben, Tswalu Kalahari Reserve. Afring News 42: 29 – 31.

De Swardt, D. H. 2013. White-backed Vultures nesting on electricity pylons in the Boshof area, Free State, South Africa.Vulture News 65: 48 – 49.

De Swardt, D. H. 2013. New distribution records: Black-backed Puffback and Barred Wren-warbler in the Free State. Ornithological Observations 4: 69-71.

De Swardt, D. H. 2012. Nature recycles: Egyptian Goose breeding in an old Secretarybird nest. Ornithological Observations 3: 223-224.

De Swardt, D. H. 2012. Bird species captured in Protea roupelliae woodland and their association with Protea habitats. Ornithological Observations 3: 29-37.

De Swardt, D. H. 2012. Suburban garden bird ringing: some ringing and recapture data over a period of nine years. Afring News 41: 16-18.

De Swardt, D. H. 2012. 2925BD Hagesdam - SABAP1 and SABAP2 compared. Ornithological Observations 3: 109-122.De Swardt, D. H. 2011. Late-summer breeding record for Secretarybirds Sagittaruis serpentaruis in the Free State. Gabar 22:31-33.

De Swardt, D. H. 2011.  Unusual egg coloration in Three-banded Plover Charadruis tricollaris. Ornithological Observations 2: 60-61.

De Swardt, D. H. 2011. Gurney’s Sugarbird project and Safring ringing data. Afring News 40: 25-26.

De Swardt, D. H. 2010. Individual and inter-population variation in African Rock Pipit Anthus crenatus songs. pp. 105-112. In: Harebottle, D.M., Craig, A.J.F.K., Anderson, M.D., Rakotomanana, H. & Muchai, M. (eds). Proceedings of the 12th Pan-African Ornithological Congress, 2008. Cape Town, Animal Demograpghy Unit.

De Swardt, D. H. 2010. Egyptian Goose Alopochen aegyptiaca hybridizes with Common Shelduck Tadorna tadorna. Ornithological Observations 1:63-64.

De Swardt, D. H. 2010. Notes on the breeding and breeding success of Crowned Lapwings Vanellus coronatus in the southern suburbs of Bloemfontein. Ornithological Observations 1: 48-51.

De Swardt, D. H. 2010. Jacobin Cuckoo parasitising African Red-eyed Bulbul nest. Ornithological Observations1: 3-4.

De Swardt, D. H. & Van der Westhuizen, A. C. 2010. First Sectretarybirds Saggitaruis serpentaruis ringed with patagial tags in the Free State. Gabar 21: 56-59.

De Swardt, D.H. 2008. Brimstone (Bully) Canaries Crithagra sulphuratus in the Zastron district, south–eastern Free State. Bird Numbers 14: 20–21.

De Swardt, D.H. 2008. Family Promeropidae (Sugarbirds). Pp. 486-497. In: del Hoyo, J., Elliott, A. & Christie, D.A. (eds). (2008). Handbook Birds of the World. Vol 13. Penduline-tits to Shrikes. Lynx Edicions, Barcelona.

De Swardt, D.H. 2007. Another record of a Secretarybird Sagittaruis serpentaruis pair raising three nestlings in the Free State, South Africa. Gabar 18 (2): 9-16.

De Swardt, D.H. 2006. Singing behaviour and perch use of male African Rock Pipits Anthus crenatus. Navors. Nas Mus., Bloemfontein 22: 129-144.

De Swardt, D.H. 2006. Bully Canaries in the Zastron district, southeastern Free State. Bee-eater 57: 4-5.

De Swardt, D.H. 2006. Jackal Buzzard Buteo rufofuscus nesting in an Olive tree in the southern Free State. Gabar 17: 20.

De Swardt, D.H. 2006. Verreauxs’ Eagle Aquila verreauxi breeding on a vodacom structure – with a sad ending. Gabar 17: 23 - 24.

De Swardt, D.H. 2006. Lanner Falcon Falco biarmicus attacking a Black-bellied Bustard Lissotis melanogaster. Gabar 17: 22-23.

Szép, T., Møller, A.P., Piper, S., Nuttall, R., Szabo, Z.D. & Pap, P.L. 2006. Searching for potential wintering and migration areas of a Danish Barn Swallow population in South AFrica by correlating NDVI with survival estimates. J. Ornithol. 147(2): 245-253. 

De Swardt, D.H., Grobler, G.P.J., Nuttall, R.J. & Oschadleus, H.D. 2005. Bishop’s Glen Ringing Project – valuable recapture data obtained after ten years. Afring News 34: 21 - 29.

Nuttall, R.J. 2005. Locustfinch. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. p 1038.

Nuttall, R.J. 2005. Orange-breasted Waxbill. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1039-1040.

Nuttall, R.J. 2005. African Quail Finch. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1040-1041.

Nuttall, R.J. 2005. Yellow-bellied Waxbill. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1043-1044.

Nuttall, R.J. 2005. Swee Waxbill. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1044-1045.

Nuttall, R.J. 2005. Black-faced Waxbill. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1047-1049.

Nuttall, R.J. 2005. Grey Waxbill. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1049-1050.

Nuttall, R.J. 2005. Cinderella Waxbill. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. p 1050.

Nuttall, R.J. 2005. Common Waxbill. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1051-1052.

Nuttall, R.J. 2005. Violet-eared Waxbill. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1053-1054.

Nuttall, R.J. 2005. Blue Waxbill. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1054-1056.

Nuttall, R.J. 2005. Bronze Mannikin. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1065-1067.

Nuttall, R.J. 2005. Magpie Mannikin. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1067-1068.

Nuttall, R.J. 2005. Red-backed Mannikin. In: Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. (eds) Roberts Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town. pp 1068-1069.

De Swardt, D.H. 2004. Greatest longevity record for Gurney’s Sugarbird Promerops gurneyi. Afring News 33: 38-39.

De Swardt, D.H., Grobler, G.P.J. & Oschadleus, H.D. 2004. Bird ringing in the Free State National Botanical Gardens, Bloemfontein, with notes on recaptures. Afring News 33: 65-70.

De Swardt, D.H., Symes, C.T. & Downes, C.T. 2004. An analysis of biometric data of the Malachite Sunbird Nectarinia famosa from five regions in South Africa. Afring News: 33: 10-14.

Hulley, P.E., Craig, A.J.F.K., Underhill, G.D., Bonnevie, B.T., Nuttall, R.J. & De Swardt, D.H. 2004. Timing of moult and breeding in the Cape White-eye, Zosterops pallidus, from three different geographical regions in South Africa. Emu 104: 353-358.

Kopij, G., Nuttall, R.J. & De Swardt, D.H. 2004. An analysis of avian (Aves) stomach contents from South Africa. Durban Museum Novitates 29: 21-30.

De Swardt, D.H. 2003. Malachite Sunbird recaptured after ten years. Afring News 32: 11.

De Swardt, D.H. 2003. Another Secretarybird breeding attempt near Hagesdam, Bloemfontein. Bird Numbers 12:47.

De Swardt, D.H. & Nuttall, R.J. 2003. An analysis of road-killed bird specimens in the collection of the Ornithology Department, National Museum, Bloemfontein. Bird Numbers 12: 13-16.

De Swardt, D.H. 2002. Moult and eclipse plumage of Malachite Sunbird Nectarinia famosa in the Free State, South Africa. Ostrich 73:176-178.

De Swardt, D.H. 2002. Notes on breeding biology of the Rock Pipit Anthus crenatus. Ostrich 73: 170-171.

De Swardt, D.H. 2002. Breeding observations on nest of Secretarybird. Bird Numbers 11: 29-31.

Kopij, G., De Swardt, D.H. & Nuttall, R.J. 2002. Diet of pipits in South African grassland. Ostrich 73: 71-73.

De Swardt, D.H. 2001. Preliminary observations on Malachite Sunbird movements in the Free State. Ostrich 72: 203-206.

De Swardt, D.H. 2001. Notes on the post-nestling period and breeding success of Gurney’s Sugarbird, Promerops gurneyi. Ostrich 72: 200-201.

De Swardt, D.H. 2001. Nestlings and nestling period of the Longbilled Pipit Anthus similis. Bird Numbers 10: 36.

De Swardt, D.H. & Peach, W.J. 2001. Annual survival of Gurney's Sugarbird Promerops gurneyi. Ostrich 72: 206-209.

Nuttall, R.J., Kleynhans, H.J., Kleynhans, J., De Swardt, D.H. & Van Der Walt, S. 2001. First record of Bartailed Godwit Limosa lapponica in the Free State, South Africa. Bird Numbers 10: 59.

De Swardt, D.H. 2000. The birds of Soetdoring Nature Reserve and adjacent areas, central Free State. BirdLife South Africa guide pp. 1-40. BirdLife South Africa: Johannesburg.

De Swardt, D.H. 2000. Moult and eclipse plumages of Malachite Sunbirds in the Free State. Safring News 29:27.

De Swardt, D.H. 2000. Incubation and nestling period of Bokmakierie Telophorus zeylonus. Bird Numbers 9: 23.

Kopij, G., De Swardt, D.H. & Nuttall, R.J. 2000. Diet of seven coraciiform species (Coraciiformes) in South Africa. Acta Ornithologica 35: 207-209.

Kopij, G., Kok, O.B. & Nuttall, R.J. 2000. Breeding cycle of the Southern Bald Ibis, Geronticus calvus. Ostrich 71(3&4): 393-399.

Nuttall, R.J. 2000. Delegorgue's Pigeon. In: The Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland. Barnes, K.N. (ed.). pp. 109-111. BirdLife South Africa: Johannesburg.

Barnes, K.N., Colahan, B.D., Nuttall, R.J. & Taylor, P.B. 1998. Important Bird Areas of the Free State. In: Important Bird Areas of southern Africa. Barnes, K.N. (ed.) pp. 123-139. Johannesburg: BirdLife South Africa.

De Swardt, D.H. 1998. Aspects of the behaviour and ecology of Gurney's Sugarbird Promerops gurneyi Verreaux, 1871, in Protea woodland, South Africa. Unpublished MSc thesis. University of the Free State: Bloemfontein.

De Swardt, D. H. & Griesel, R. 1998. The Redthroated Wryneck in the southern Free State. Bird Numbers 7: 25.

Kopij, G. & De Swardt, D.H. 1998. Breeding ecology of the Little Swift Apus affinis, in Bloemfontein, South Africa. Navors. Nas Mus., Bloemfontein 14: 145-159.

Nuttall, R.J., Allan, D.G., Underhill, L.G. & Lockwood, G. 1998. Priorities for bird conservation in South Africa. Johannesburg: BirdLife South Africa. pp. 17.

De Swardt, D.H. 1997. Gurney's Sugarbird Promerops gurneyi. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 486-487. BirdLife South Africa: Johannesburg.

De Swardt, D.H. & Schoeman, S. 1997. Sunbird recaptures and seasonal movements at Lydenburg, Mpumalanga Province. Safring News 26:13-15.

Nuttall, R.J. 1997. Delegorgue's Pigeon Columba delegorguei. In: The atlas of southern African birds. Vol. 1: Non-passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), p. 501. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Blackcollared Barbet Lybius torquatus. In: The atlas of southern African birds. Vol. 1: Non-passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 710-711. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Pied Barbet Tricholaema leucomelas. In: The atlas of southern African birds. Vol. 1: Non-passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), p. 712-713. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Crested Barbet Trachyphonus vaillantii. In: The atlas of southern African birds. Vol. 1: Non-passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), p. 724-725. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Cape White-eye Zosterops pallidus. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 526-527. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Yellow White-eye Zosterops senegalensis. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 528-529. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Brown Firefinch Lagonosticta nitidula. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), p. 601. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Bluebilled Firefinch Lagonosticta rubricata. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 602-603. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Jameson's Firefinch Lagonosticta rhodopareia. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 604-605. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Redbilled Firefinch Lagonosticta senegala. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 606-607. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Quail Finch Ortygospiza atricollis. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 622-623. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Bronze Mannikin Spermestes cucullatus. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 630-631. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Redbacked Mannikin Spermestes bicolor. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 632-633. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Yelloweyed Canary Serinus mozambicus. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 650-651. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Blackthroated Canary Serinus atrogularis. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 652-653. BirdLife South Africa: Johannesburg.

Nuttall, R.J. 1997. Streakyheaded Canary Serinus gularis. In: The atlas of southern African birds. Vol. 2: Passerines. Harrison, J.A., Allan, D.G., Underhill, L.G., Herremans, M., Tree, A.J., Parker, V. & Brown, C.J. (eds), pp. 672-673. BirdLife South Africa: Johannesburg.

De Swardt, D.H. & Van Niekerk, D.J. 1996. An annotated check list of the birds of Qwaqwa National Park. Koedoe 39:89-106.

Nuttall, R.J. 1996. Notes on Delegorgue's Pigeon Columba delegorguei in the Karkloof, KwaZulu-Natal, South Africa. Ostrich 67:45-46.

De Swardt, D.H. 1995. Malachite Sunbird ringing in the Free State. Safring News 24:15-18.

De Swardt, D.H. 1995. Bird survival data from the Oliewenhuis Gardens, central Bloemfontein. Safring News 24: 59-61.

De Swardt, D. 1995. Voëlberinging kan gevaarlik wees. Safring News 24: 83-84.

Nuttall, R.J. 1995. Lesser Spotted Eagle Aquila pomerina at Zastron, southeastern Free State Province, South Africa. Journal of African Raptor Biology 10:35-36.

De Swardt, D.H. 1994. Identification problems during bird ringing - the Whitethroat example! Safring News 23: 22-23.

De Swardt, D.H. & Louw, S. 1994. The diet and foraging behaviour of Gurney's Sugarbird Promerops gurneyi. Navors. nas. Mus., Bloemfontein 10: 245-258.

Bates, M.F. & De Swardt, D.H. 1994. Mabuya variegata punctulata, Mabuya striata sparsa and Meroles suborbitalis: Avian predation. African Herp. News 21: 18-19.

De Swardt, D.H. 1993. Factors affecting the densities of nectarivores in Protea roupelliae woodland. Ostrich 64: 172-177.

Nuttall, R.J. 1993. Seasonal changes in the birdlife of a peri-urban grassland community. Ostrich 64: 1-7.

Nuttall, R.J. 1993. Vocal behaviour of the Quail Finch Ortygospiza atricollis. Ostrich 64: 94-107.

Bates, M.F., De Swardt, D.H. & Louw, S. 1992. A note on the diet of the Yellowbilled Egret. Ostrich 63(1): 44.

De Swardt, D.H. 1992. A behaviour study of the Black Korhaan Eupodotis afraoides. Navors. nas. Mus., Bloemfontein 8(6): 237-258.

De Swardt, D.H. 1992. Distribution, biometrics and moult of Gurney's Sugarbird Promerops gurneyi. Ostrich 63: 13-20.

De Swardt, D.H. 1992. Rednecked Falcons in the western Orange Free State, South Africa. Gabar 7: 69.

De Swardt, D.H. 1992. Some interesting recaptures at the Oliewenhuis Gardens, central Bloemfontein. Safring News 21: 15-16.

De Swardt, D.H. & Bothma, N. 1992. Notes on the breeding biology of Gurney's Sugarbird. Ostrich 63: 136-137.

De Swardt, D.H. & Buys, P.J. 1992. Cape Sugarbird at Jagersfontein, southern Orange Free State. Ostrich 63: 136.

Nuttall, R.J. 1992. Methods for trapping Quail Finches Ortygospiza atricollis. Safring News 21: 55-59.

Nuttall, R.J. 1992. Breeding biology of the Quail Finch Ortygospiza atricollis. Ostrich 63: 110-117.

De Swardt, D.H. 1991. Measurements and moult in the Greater Double-collared Sunbird. Safring News 20: 21-25.

De Swardt, D.H. 1991. The seasonal movements of Gurney's Sugarbird Promerops gurneyi in the Lydenburg area, Transvaal. Ostrich 62: 40-44.

Earlé‚ R.A. 1991. Bee-eaters taking earthworms on the ground. British Birds 84(2): 61-62.

Earlé‚ R.A., Bennett, G.F., Du Toit, H., De Swardt, D.H. & Herholdt, J.J. 1991. Regional and seasonal distribution of avian blood parasites from northern South Africa. S. Afr. J. Wild. Res. 21: 47-53.

Nuttall, R.J. 1991. Marsh Owls Asio capensis hawking termite alates. Mirafra 8: 57-58.

Nuttall, R.J. 1991. Eastern Saw-wing Swallow and Black-eared Canary observations. Honeyguide 37: 77-78.

Nuttall, R.J. 1991. Feeding association during termite emergence. Honeyguide 37: 78-80.

Bates, M.F. & De Swardt, D.H. 1990. Life History note: Cacosternum boetgeri and Xenopus laevis laevis: Avian predation. J. Herp. Assoc. Afr. 37: 46.

Bennett, G.F., Pierce, M.A. & Earlé, R.A. 1990. The haemoproteids of the shrikes of the avian family Laniidae (Passeriformes). S.A. J. Zool. 25(3): 194-198.

De Swardt, D.H. 1990. Ageing and sexing Gurney's Sugarbird Promerops gurneyi. Safring News 19: 57-60.

De Swardt, D.H. 1990. Birds of the Gustav Klingbiel Nature Reserve and Sterkspruit area, Lydenburg. Southern Birds 16: 1-67.

De Swardt, D.H. 1990. Growth and behaviour of Secretarybird nestlings. Gabar 5: 22.

De Swardt, D.H. 1990. Pygmy Falcon catches Sociable Weaver in flight. Gabar 5: 27.

Kok, O.B. & Earlé, R.A. 1990. Diet of the Black Korhaan Eupodotis afra in the Orange Free State and north-west Cape. Ostrich 61(3/4): 107-110.

Crowe, T.M., Kemp, A.C., Earlé, R.A. & Grant, W.S. 1989. Systematics is a most essential, but most neglected biological science. S. Afr. Journ. Sci. 85: 418-423.

De Swardt, D.H. 1989. Some observations on the local movements of Gurney's Sugarbird in the Lydenburg area. Safring News 18: 31-32.

Earlé‚ R.A. 1989. Breeding biology of the Redbreasted Swallow Hirundo semirufa. Ostrich 60: 13-21.

Earlé‚ R.A. 1989. The importance of temporary pans to birds in the central Orange Free State. Naturalist 33: 8-12.

Earlé‚ R.A. & Brooke, R.K. 1989. Taxonomy, distribution, migration and moult of the Redbreasted Swallow Hirundo semirufa. Ostrich 60: 151-158.

Kemp, A., Earlé‚ R.A., Mendelsohn, J., Vernon, C., Harris, T., Komen, J. & Berrutti, A. 1989. Systematic theory and practice applied to avian research and collections at South African and Namibian Museums. Samab 18(7): 265-270.

Oatley, T.B., Earlé, R.A. & Prins, A.J. 1989. The diet and foraging behaviour of the Ground Woodpecker. Ostrich 60: 75-84.

De Swardt, D.H. 1988. Blackshouldered Kite breeding in summer at Roodeplaat-dam Nature Reserve, South Africa. Gabar 3: 101-102.

Earlé‚ R.A. 1988. The timing of breeding and moult in the Lesser Striped Swallow. Ibis 130: 378-383.

Earlé‚ R.A. 1988. The timing of breeding and moult in three African Swallows. Revue Zool. afr. 192: 61-70.

Earlé‚ R.A. 1988. A cast-net for trapping nightjars (and others). Safring News 17: 25-28.

Earlé‚ R.A. 1988. Nest rotation by Whitethroated Swallows during the breeding season. Hirundo 1: 11-12.

Earlé‚ R.A. & Herholdt, J.J. 1988. Breeding and moult of the Anteating Chat Myrmecocichla formicivora. Ostrich 59: 155-161.

Earlé‚ R.A. & Lawson, A.B. 1988. An annotated checklist of the birds of the Golden Gate Highlands National Park. Koedoe 31: 227-243.

Earlé, R.A. & Louw, S. 1988. Diet of the Anteating Chat Myrmecocichla formicivora in relation to terrestrial arthropod abundance. S. Afr. J. Zool. 23(3): 224-229.

Earlé, R.A., Louw, S. & Herholdt, J.J. 1988. Notes on the measurements and diet of Ludwig's Bustard Neotis ludwigii. Ostrich 59(4): 178-179.

Farkas, T.B. 1988. The birds of Korannaberg, eastern Orange Free State, South Africa. Navors. nas. Mus., Bloemfontein 6(3).

Herholdt, J.J. 1988. An albino Red Bishop in OFS. Bokmakierie 40: 22.

Herholdt, J.J. 1988. The distribution of Stanley's and Ludwig's Bustard in southern Africa: a review. Ostrich 59: 8-13.

Herholdt, J.J. & Grobler, N.J..1988. Dimensions of Botha's Lark Spizocorys fringillaris. Ostrich 59: 47.

Earlé‚ R.A. 1987. A case of bigamy in the Redbreasted Swallow Hirundo semirufa. S. Afr. J. Zool. 22: 325-326.

Earlé‚ R.A. 1987. Distribution, migration and timing of moult in the South African Cliff Swallow. Ostrich 58: 118-121.

Earlé‚ R.A. 1987. Homing ability of the South African Cliff Swallow. Safring News 16: 3-7.

Earlé‚ R.A. 1987. Moult and breeding seasons of the Greyrumped Swallow. Ostrich 58: 181-182.

Earlé‚ R.A. 1987. Measurements, moult and timing of breeding in the Blue Swallow. Ostrich 58: 182-185.

Earlé‚ R.A. 1987. Notes on Hirundo fuliginosa and its status as a "Cliff Swallow". Bull. Brit. Orn. Club. 107: 59-63.

Earlé‚ R.A. 1987. Ringing and recovery details of four swallow species in southern Africa. Safring News 16: 67-72.

Earlé‚ R.A. & Grobler, N.J. 1987. First atlas of bird distribution in the Orange Free State. Bloemfontein: National Museum.

Earlé‚ R.A. & Herholdt, J.J. 1987. Notes on a Greater Honeyguide Indicator indicator chick raised by Anteating Chats Myrmecocichla formicivora. Bull. Brit. Orn. Club 107: 70-73.

Earlé‚ R.A. 1986. Dimensions and deformaties of South African Cliff Swallow. Ostrich 57: 56-59.

Earlé‚ R.A. 1986. Reappraisal of variation in the Ground Woodpecker Geocolaptes olivaceus (Aves: Picidae). Navors. nas. Mus., Bloemfontein 5(7): 79-93.

Earlé‚ R.A. 1986. The breeding biology of the South African Cliff Swallow. Ostrich 57: 138-156.

Earlé‚ R.A. 1986. Time budget of South African Cliff Swallows during breeding. S. Afr. J. Zool. 21: 57-59.

Earlé‚ R.A. 1986. Vocalizations of the South African Cliff Swallow Hirundo spilodera. S. Afr. J. Zool. 21: 229-232.

Earlé‚ R.A. & Herholdt, J.J. 1986. Co-operative breeding in the Anteating Chat. Ostrich 57: 188-189.

Herholdt, J.J. 1986. Occurrence of the Barred Warbler in the Orange Free State. Osrich 57: 114.

Herholdt, J.J. 1986. Diet of the Barn Owl at a riverine roost in the central Orange Free State. Ostrich 57: 185-187.

Herholdt, J.J. & Earlé‚ R.A. 1986. Ashy Tit and Pied Barbets roosting in a sandbank. Ostrich 57: 64.

Earlé‚ R.A. 1985. A description of the social, aggressive and maintenance behaviour of the South African Cliff Swallow Hirundo spilodera (Aves: Hirundinidae). Navors. nas. Mus., Bloemfontein 5(3): 37-50.

Earlé, R.A. 1985. Ageing and sexing guide - South African Cliff Swallow Hirundo spilodera. Safring News 14: 48.

Earlé‚ R.A. 1985. Predators, parasites and symbionts of the South African Cliff Swallow Hirundo spilodera (Aves: Hirundinidae). Navors. nas. Mus., Bloemfontein 5(1): 1-18.

Earlé‚ R.A. 1985. The nest of the South African Cliff Swallow Hirundo spilodera (Aves: Hirundinidae). Navors. nas. Mus., Bloemfontein 5(2): 21-36.

Earlé‚ R.A. 1985. Foraging behaviour and diet of the South African Cliff Swallow Hirundo spilodera (Aves: Hirundinidae). Navors. nas. Mus., Bloemfontein 5(4): 53-66.

Farkas, T.B. 1981. Bird communities of the False Upper Karoo. Mem. Nas. Mus., Bloemfontein. 16: 1-160.