The Cape Bird Club
Western Cape Raptor Research Programme
WEST COAST BLACK HARRIER SURVEY REPORT by Rob Simmons
photograph by Rob Simmonds
Black Harrier with satellite tag.
December 2008 Rob reports, On
Satalite tagging - "Motlanthe the male harrier feeding two young in the West Coast NP is busy re-writing the text books.
He was photographed mid November by Mark Anderson, feeding his 2 youngsters, with his transmitter functioning well and looking good. In 7 days (11 Dec) he will have worn it for 2 months.
We had previously radio-tracked male harriers in Bontebok by sight to about 3 km and all tagged males had been seen at this (max) distance. Motlanthe was regularly seen 10 - 15 km from his nest!
As the kids got older he was tracked to 30 km, then 40 km and once (last week) to 50 km from his nest. These last two readings were poor accuracy so they need to be confirmed but what we can say is that (i) he is slowly extending his foraging range (ii) he hunts mostly over natural vegetation and (iii) he roosts well away from the children now!
A second bird - a female (yet to be named.... suggestions) was caught (on a trap made by Ann Koeslag) and tagged yesterday at Koeberg (aided by Cat and Julia Simmons).
She is already sending signals and last night was 160 metres from her nest at a usual roost site.
If she is as half as successful as Motlanthe then she will have done a good job!
Names please.....".
- Koeberg 3 nests ... one successful, others both subsequently hatched by December (late!)
- Jakkalsfontein 2 nests still with eggs (1 female egg laying late Nov!)
- Rondeberg 2 nests still active brood of 3 and a pair ready to lay
- WCNP 5 nests still with eggs all very late.
October 2008 Rob reports, "The exciting news is that the first harrier in southern Africa has been successfully satellite tagged. The tiny (12.5g) satellite tags I have for following Black Harriers was (solar) charged in early October and the first one attached to a breeding male on the west coast in October with the help of Phoebe Barnard and Esme Beamish (best known for her baboon studies).
The device is attached with a harness to the bird and then 5 to 10 fixes a day (mainly in a 5 h block in the afternoon) show where the bird is. He is foraging in farmland at least 17 km from his nest - a huge surprise given that we have never seen a marked male farther than 3 km from his nest site!!
We hope to pop another 2 transmitters on before the end of October and the whole process may be filmed by a local company. The really exciting times come when the birds leave their breeding grounds in December / January and head north to destinations unknown. Because each transmitter is solar powered we should be able to follow these birds for more than a year!
Special thanks to all those who made this possible - Natural Research (UK) for funds, (especially Mike McGrady and Ruth Tingay), Keith Bildstein and Dave Barber at Hawk Mt (USA) for transmitters and advice, and Francois Mougeot and Beatriz Arroyo for teflon and valuable input".
29/07/2008 - Good news from the West Coast here is that we have the first nest of the season.
Following news from keen harrier watcher Carrots Doyle, I paid a quick visit to Jakkalsfontein private nature reserve and found the
female with three eggs (photo). She appears pregnant still (photo) so there may be room for more eggs, but its too early to count our chickens!
photographs by Carrots Doyle
Pregnant female Harrier Nest with eggs
This is often the first place for harrier breeding, but she is not necessarily alone. I have seen other birds carrying food and there are reports from De Hoop of food-carrying birds, and more sightings of birds in the western Cape here (Barrydale, Tanqua Karoo, Tulbagh area, Bot River).
Please continue to send all reports of harriers to me and especially those nest-building or carrying food. The main egg-laying months are August and by September there will be lots if chick-feeding activity.
Contact;
Rob Simmons tel 021 650 3310 or fax 021 650 3295 harrier@botzoo.uct.ac.za
