Richmond Parakeet

I have a little ongoing project to try and get some decent shots of the wild parakeets in Richmond Park. They're tricky as they move around a lot, and as you might expect they're generally right in the top of a very tall tree (!).

This is my favourite shot from yesterday morning - the chap was a long way away, very high up in a big tree and it was pretty murky and overcast. I was on ISO400 and its a bit of a crop from the full picture so it's a bit grainy...

Any tips from other bird photographers warmly received... having studied the parakeets for a few weeks now I am understanding where they go and what they do which is proving very helpful to at least find them in the first place!