To be fair though, Roy, you obviously had plenty of light for those, up to 1/2500th I see!
OS isn't really designed for days like that is it?
It can work wonders on dismal days or even in the woods on sunny days, though. I wouldn't be without it personally, Sigma 150-500 OS by the way
These days Daron I work on a simple principle with the birding lens, if the light is not good enough to get me the shutter speed I want (at up to ISO 1600) then I am not bothered about shooting at all - the more I have been at this game the more I realise that light is everything.
Just this week I was out on a poor light day (against my better judgement :bang

shooting perched Swallows from around 5 metres with the 400 and a tripod with gimbal head, got loads of sharp shots but binned the lot as the light was just not good enough as far as I was concerned, the pics just did not pop even after playing around on CS5 for an hour or so. In the end I just deleted the whole folder.
If you do like shooting hand held on dismal days or in dark woods then IS/OS obviously helps. I came from the Canon 300/2.8 IS lens less than a year ago and can honestly say I do not miss the IS at all. That's not to say that I would not get another birding lens with IS but for me it is just a case of adapting my technique to suit the gear I am shooting with.With the 400/5.6 when hand holding I look for a minimum of 1/800-1/1000 sec for perched birds but if the light is really good I will not hesitate in upping the shutter speed.
Of course when you are on high(ish) ISO's on a Camera like the 7D it helps enormously to ETTR - I also use AI servo all the time together with back button focusing, when shooting perched birds like waders that are constantly on the move I actual find it an advantage not to use IS even if I had it (I often turned it off on the 300/2.8).
My whole point is that it is possible to get reasonable bird pics with a non IS lens - when I bought my current 400/5.6 (used) I was fully aware that I could have got a brand new lens like the 150-500 sigma for a little less than I paid but for me there was no contest (but then I am somewhat biased toward Canon L lenses).
I do believe that too many people these days assume that just because they have a IS/OS lens then all they have to do is press the shutter regardless of shutter speed and good shots are guaranteed - there is a lot more to it I believe.
Anyway that's enough from me, just enjoy your photography no matter what gear you have.