The group of 4 Americans consist of Greg who is leading the photographic birding tour and 3 clients (although they've all been with him on so many trips they're more like friends).
For this trip I've hired a 100-400 lens to see if it would be worth buying one and so far I'm not too impressed with the results as nothing seemed particularly sharp. I mentioned this to Greg who asked if I'd micro adjusted it - something I'd never heard of. He then proceeded to adjust both this lens and my own 70-200 and the difference is just amazing (probably won't be too noticeable on these small images but it is a vast difference.
A few more from this afternoon, probably much the same as this morning but I can't resist especially the hummingbirds, some of which are so hard to tell apart so I won't name them :) and they are just pictures of "birds on a stick" so I don't think I'll be sharing them with anyone. They are without a doubt the most challenging thing I've tried photographically.
Sadly Greg and his party leave tonight but I have his website and who knows, maybe a birding-photography holiday somewhere with him may happen in the future.