A RARE VISITOR TO THE CAMDEBOO MOUNTAINS

 

Camdeboo had a new and rare visitor recently and she had flown almost 6000 km in the last 6 months to settle in the mountains above Aberdeen. 

She is a Black Harrier (Witkruis padervreter) – a bird of prey that breeds only in South Africa and is highly threatened. Numbering about 700 pairs in the world, their numbers are low because their habitat – Fynbos and grasslands in coastal and mountainous regions of South Africa - is being swallowed up and degraded by man. These beautiful black birds travel far and wide looking for suitable places to build their small ground nests and they are being studied with the aid of miniature satellite trackers by researchers from the FitzPatrick Institute at the University of Cape Town.

The visiting bird, called Moraea (after the rare and elegant iris-like flowers) has been followed since November last year on a remarkable journey that has seen her travel 5800 km from her home near Langebaan, via Lesotho, to the Camdeboo Mountains in just 6 months. Her journey started in the West Coast National Park where she was breeding in September 2010 in the vleis around Langebaan Lagoon. There she reared two young on a diet of rats, mice and small birds. Following their independence, she left the park in February 2011 and she raced 1200 km across the hot dry Karoo and into the Drakensberg in just 6 days to settle around the highlands of Sani Pass. Preferring the cool high places she stayed in Lesotho for 2 months, visiting at one stage the highest point in southern Africa (Thabana Ntlenyana) at 3482 m above sea level. There it is likely that she was feeding on Ice Rats, small mammals that breed in the alpine grasslands in March and April. She moved out slowly in April 2011 to the Transkei, and then visited Engcobo in the Eastern Cape for 2 months, before heading back 1240 km across the Karoo in 6 days to briefly visit her old haunts in Langebaan in mid July. Not liking what she found there in an unusually dry winter in the Western Cape, she headed back to Beaufort West in late July, and passed through Aberdeen on her way back to Engcobo. In early August she once turned around and headed west  for Aberdeen and first visited the Camdeboo Mountains on 12 August 2011. She subsequently stayed, attracted by the above average rainfall that had fallen on The Ranges farm owned by Pen and Hester Marx. Other Black Harriers were also attracted by the rains that had swollen the mouse population and she began breeding with her mate in early September in the vleis above the farm. Visiting the farm, researcher Dr Rob  Simmons and his daughter Cat, found her and her nest with 3 large chicks doing very well on 5-6 November – a year after she was first tagged in Langebaan, and a mere 5800 km later.

 

We were able to follow her remarkable journey with miniature high-tech trackers that pinpoints her position accurately anywhere on the surface of the earth. Weighing a mere 12.5 g and powered by a miniature solar panel, they do not encumber the birds and their presence is only given away by a short aerial protruding from the back feathers. The satellite tag communicates with Argos satellites overhead and allows researchers to follow the bird’s journey and determine the distances covered on a daily basis. Moraea has worn her tag for a year now, and has provided researchers with an unparalleled window into a migration of this rare bird of prey previously unsuspected and unknown.

We hope to follow her subsequent journeys after breeding and reveal more of the lives of these remarkable birds of prey.

 

 

Rob Simmons

 

FitzPatrick Institute

 

The track of Moraea, the satellite-tagged Black Harrier, from February to November 2011. Starting in Langebaan in February she flew (pink line) 1200 km to Sani Pass in 6 days. Returning slowly (Blue line) via Engcobo and Somerset East to Langebaan in July 2011 she immediately turned back to Beaufort West and flew on to Engcobo (red line) in August. From Engcobo she flew back (green line) to Aberdeen to settle in the Camdeboo Mountains to breed in September – November. A total journey of 5800 km. © R.E. Simmons.

 

Moraea, the Black Harrier female on route to her breeding grounds in The Ranges, in the Camdeboo mountains near Aberdeen. The satellite tracker aerial is visible protruding from her back feathers. © R.E. Simmons.

 

 

 

 

 

 

 

 

 

 

Moraea, the female Black Harrier foraging over the marshlands at The Ranges in the Camdeboo Mountains, looking for mice. The satellite tag allowing researchers to follow her journey is visible in the centre of her back with the aerial facing backwards. © R.E. Simmons.