Thank you for that most interesting info Johan.
Here's some more...
I referred earlier to vultures that were fitted with radio transmitters last year. Two of those were young Bearded Vultures. The elder, named Daniel, is a three year old male and a two-year-old female, Andalucia, both recently shed their transmitters.
The research team realised something was amiss when incoming data indicated that both transmitters had stopped moving. Initially it was feared that the birds were dead. A search in the Kamsberg area produced neither the device nor an injured nor any sign of Daniel. Since Andalucia’s data comes Spain, it took a while for the tracking team to realise that her transmitter was also no longer moving. It is located on the escarpment on the Lesotho/Eastern Cape border and is logistically more difficult to search for.
Daniel's transmitter was found quite quickly by searching for the device's UHF frequency with a receiver and antennae. The UHF frequency is one with which the device communicates with the satellite and is not meant to be used to "track" the device, but in this case it worked quite well. It seems the device fell off the bird and it is assumed that Daniel is still alive and well.
The second rescue mission has so far produced neither sign of Andalucia nor the transmitter. Nearby where the last data originated from is a little settlement of Basotho homesteads and animal kraals. It is thought that a herdsman or even a child may have picked up the transmitter. Andalucia’s fate is presently still unknown.
Bearded vultures don’t breed until they are five or six years old and then they pair up for life. The worrying thing is that it is the juveniles of one or two years old that are being wiped out and no one is quite sure why or how. The GPS transmitters that were fixed to Daniel and Andalucia are part of the project to find out.
Precious funding has been sourced so that next year about 20 juvenile vultures can be tagged and the slow work of investigating what causes their demise can continue.
The research team has since adapted the harness, as they have done in Europe, using a second, wider band of Teflon to ensure that it and the device stay on the birds. The transmitters cost between R25 000 and R30 000, not counting all the logistical arrangements to catch the birds. It took 4 weeks of field work to perfect a technique to catch 3 birds last year! Add to that the R1000 monthly fee for the downloading of the satellite data from a French satellite and you have an understanding of the expense involved in monitoring the bearded vultures.