I've always favoured primes for wildlife, I'd suggest its worth considering a 400mm f/5.6 too. You lose a lot of flexibility but gain on sharpness and size.
Sigma 100-300 f/4 was my choice (for IQ) with the option of a 1.4 TC on top of that
70-200 with the 1.4 TC would make it 280mm not 320mm n'est pas?
Sigma 70-200 f/2.8 + 1.4x TC - £994.83Sigma 70-200 f/2.8 + 2x TC - £1024.83Canon 70-300 L = £1077
Canon 400mm f/5.6 ~ £700-800 (I bought one of these, owned it for 6 months and sold it for the grand sum of £20)
Only down size is the weight, mostly hand held stuff so it becomes pretty tiring after a few hours.
QuoteCanon 400mm f/5.6 ~ £700-800 (I bought one of these, owned it for 6 months and sold it for the grand sum of £20)Jeez Paul, your bad luck never ends!
...Especially considering you already have an equivalently specced 70-300 over which gains will be small.