I do the odd tour and assist budding bird photographers shoot at MBG. Join the group on Flickr if you have any images you want to share. This shot was taken with a 1997 Sigma 170-500mm APO f/5-6.3 on a very overcast day with the light changing constantly. A great lens for those with a small budget. Can be bought 2nd hand (locally) for most mounts under $700-00 if you know where to look 
The newer Sigma 150-500mm f/5-6.3 DG OS HSM APO can be bought for around $1000-00 new (excluding shipping and taxes from USA to RSA). The local retail brick and mortar price is about $1870-00! (ZAR 12,600-00)
Gymnogene – (Polyboroides typus) (c) HarveyG Photography
Gear I use: Bodies: Nikon D-SLR’s / Lenses: Nikon, Sigma, Tokina, Vivitar /
Filters: Hoya UV & Polarizing / Flash: Nikon Speed-lights / Bag: Lowe Pro /
Tripods & Heads: Manfrotto / Grips and Batteries: Phottix
Editing Plug-in: Topaz Labs for Noise Reduction, HDR.
