What all enthusiast Nikon users need to remember is, to get the quality this Sigma zoom lens provides in good light, will cost you several thousand pounds more to achieve in less light.
I have seen these poor light shots, and to be honest, they are not a lot better than those you can achieve with good light, and a medium priced lens.
As i have always ranted. To get quality,,,,,, get close.
With wildlife photography nothing beats a hide of some sort, and a little bit of cunning. :shrug: simples!