KINGFISHER IN FLIGHT

I think I've been spoilt with my other lens - I'm not too happy at this stage with the new IS replacement - I feel confident I would have nailed this shot with the other lens - Its also overexposing a fraction with a fast shutter speed. I'm wondering if the IS doesnt like the 1.4 Extender. I will keep on ??
Anyway I was pleased to be back with one of my friendly Kingfishers. Not many around yet but they'll be back !?
rgds poo