NOTES Partial albino African Marsh Harrier at Langebaan, South Africa

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1 NOTES Partial albino African Marsh Harrier at Langebaan, South Africa Robert E. Simmons 1, Trevor Hardaker 2 & William S. Clark 3 * 1 FitzPatrick Institute, University of Cape Town, Rondebosch 7701, RSA; 2 ZEST for BIRDS, P.O. Box 50503, West Beach 7449, RSA; 3 P. O. Box , Harlingen, Texas 78550, USA, * corresponding author An unusually coloured harrier (Fig 1) was observed in the West Coast National Park, at the southern end of Langebaan Lagoon, South Africa (S E ) in 2007 and It was identified as an African Marsh Harrier Circus ranivorus by its size, shape and reed-bed location when first seen by TH in May Its plumage was unusual in that some feathers in the primaries, secondaries, nape, back, upperwing coverts, and body were completely white. Only the tail was the typical colour, with no white feathers (Fig 2). Partial albino is the term used by Sage (1962) and Ross (1963) for this plumage to distinguish this condition from full albino, when all feathers are white and body parts pink. This is the first published record of partial albinism for the African Marsh Harrier. It was assumed to be a male by its behaviour, size, and grey colouration on the uppersides of the remiges. African Marsh Harriers occur naturally in the wetlands surrounding this natural salt-water lagoon and other African Marsh Harriers were breeding and on eggs, so there is the possibility that this bird did breed and pass on this interesting aberration. However, this male did not appear to be paired and no food passes were apparent in the approx 1 hour that RES observed it on 27 September 16

2 2007 that would suggest a mate sitting tight on eggs. Too few observations were carried out, however, to confirm this. A typicallycoloured male African Marsh Harrier (judged by size and pale grey in the secondaries) was observed harassing it by RES on a subsequent sighting in September The bird was first independently observed on 5 May 2007 flying by itself by TH, who photographed the bird passing overhead (Fig 1) and again on 9 March 2008 when it was observed flying together with other individuals but not interacting directly with them. It was again seen by WSC who photographed the bird on 9 June months after the initial observations (Fig 3). It was seen flying with two juveniles on that date. The final sighting of the bird in August 2008 by RES indicated that the white feathers were retained through the moult and were not just a transient phenomena. Moult in males typically occurs after breeding in about October-November (Simmons 2005), so this bird had been through at least one full moult during our observations. Given that adult African Marsh Harriers frequently return to their breeding territory (Simmons 2005), there is a good chance that this bird will remain for the up-coming breeding season beginning in August Unusually coloured harriers often occur at the periphery of their ranges (Simmons & Simmons 2000), so this bird supports the trend occurring as it does at the south-western most corner of its African distribution. Partial albinism has been reported for three other harrier species. Watson (1977) reported eight instances of this condition in the Hen Harrier (C. cyaneus) in the western-most part of their range. Clarke (1995) reported six records of it from East Anglia in the UK for the Western Marsh Harrier (C. aeruginosus), and in the same year (1989) a brood from Holland with partially white young. This sporadic outbreak of partially white birds led Clarke (1995) to speculate whether a temporary environmental factor was at play. Bernis (1969) reported a juvenile of 17

3 this species with lots of white in the plumage, and another was reported from Italy in a different year. Finally, Buller (1877) described a partial albino specimen of the Swamp Harrier (C. approximans) and the sighting of another. So while this trait is not unheard of in other harriers, this appears to be the first such observation of a partial albino African Marsh Harrier, although dark-morph individuals have been reported by Clark (1997) from East and Southern Africa. Fig 1. The territorial partial albino African Marsh Harrier observed at Langebaan Lagoon in 2007 and 2008 (photo Trevor Hardaker). The dull grey visible on this birds secondaries identify it as a male. 18

4 Fig 2. The same African Marsh Harriers photographed in September 2007 indicating the splashed white effect on the wings and back but a lack of white on the tail (photo Rob Simmons). 19

5 Fig 3. The partial albino African Marsh Harrier showing the white extending across the back and around the rump, photographed in June 2008 (Bill Clark). Marsh harrier males typically moult after breeding (September-October) indicating that this bird moulted in white feathers the following year. 20

6 References Bernis, F [Aberrant plumages in the genus Circus.] In Spanish. Ardeola 13: Buller, W. L Further notes on the Ornithology of New Zealand. Trans. & Procs. of the Royal Society of New Zealand 10:201. Clarke, R The Marsh Harrier. Hamlyn Species Guides, London. Clark, W. S A dark morph for the African Marsh Harrier J. Afr. Raptor Biol. 12: Ross, C.C Albinism among North American birds. Cassinia 47:2-21. Sage, B. L Albinism and melanism in birds. British Birds 55: Simmons, R. E African Marsh Harrier In: Hockey, P. A. R., Dean, W. R. J., Ryan, P. G. (eds) Roberts birds of southern Africa. Pp John Voelcker Bird Book Fund, Black Eagle Publishing, Cape Town. Simmons, R. E. & Simmons, J. R Harriers of the world: their behaviour and ecology. Oxford University Press, UK. Watson, D The Hen Harrier. T. & A. D. Poyser, Berkhamsted. UK. 21