Hi Mark, I have been quite successful in getting bird shots, I see that you have a 70-300 Sigma which should be suitable. I genially shot from the kitchen window where I can rest the camera lens on my arm which in turn is holding the window frame to form a support. even in good light I would use 400ISO and a quick shutter speed and matrix metering, focusing is fixed to a single area (middle) once focused I will compose shot (this is assuming the bird is still). If you intend catching the bird in flight then you will have to rely upon continuous focusing. Plus you will need to take plenty in order to get one descent shot
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