Friday, 13 September 2013

The Beautiful Black Harrier

The Black Harrier (Circus maurus) is the most beautiful of the world's harriers, and one of the most striking of the world's raptors, most of which are shades of brown. Perhaps for this reason the species is the emblem of the Percy FitzPatrick Institute of African Ornithology (see logo on the right).

According to Birdlife SA, Black Harriers  are southern Africa’s rarest endemic raptor and will be listed in South Africa this year as Endangered, due mostly to loss of breeding habitat (lowland Renosterveld). The species is also considered to be at risk from wind turbines.

Considered a Fynbos breeding near-endemic, encounters with this species are special whenever they occur. This year I've had a string of encounters on the western edge of Baviaanskloof Nature Reserve that led me to suspect the presence of a breeding pair.

Rob Simmons (the world's leading authorities on Black Harrier, having written the guide to the raptor group) suggested I try and locate the nest, since the species is still relatively poorly understood. Black Harrier's are the focus of his research, which has recently revealed incredible migrations and movements from breeding grounds of the Western Cape to Lesotho. You can read more about the travels of the satellite collared harriers here:

Today's survey started auspiciously as within a minute of my first point count, a harrier zoomed over the nearby ridge. It flew straight towards me, before veering off at about 50m distance and continuing a low foraging flight away over the dry renosterveld. This location is about 2 km from where I had seen the harriers on two previous surveys.

Following up on Rob Simmon's advice, I made an effort to locate the Black Harrier nest site – as there are no previous breeding records from this region.

At about 9am I approached a point about 500m away from where I expected the nest to be, and observed the male Black Harrier foraging for about 15 minutes. While I did not observe a food drop, some unusual behaviour, coupled with a sighting from last month gave me a good idea on where to start looking.

From the access track, I wondered down into the valley, which is dominated by the straggly shrub Stoebe burchellii and sedge. The site I initially investigated turned up blank, but while I was looking around, the male made a return to the area, and I heard a soft, rapid ke ke ke contact call. I was unsure if it was the male or a hidden female. I waited for a while, and the male came over again, and I heard the same call twice. Heading towards the noise I spotted an odd gap in a patch of sedge. Seconds later the female exploded from her hidden location. After locating the nest, I quickly left the area to observe them from a distance to check I had not caused them to abandon the site.

Female Black Harrier

Male Black Harrier

P..s off and leave me alone!

After a few minutes, they appeared to have settled. The day warmed up nicely, and the angulate tortoises were everywhere. To cap off a wonderful morning, a Karoo Tent Tortoise (rare) was also encountered.

Karoo Tent Tortoise (cousin of the endangered Geometric Tortoise)

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