Stunning pics but there is a story I'm sure behind the pics.
BIF is one of the hardest genre of photography and generally requires and demands years and years of practice - which you might have and clearly have specialized in.
To truly access the K5's true ability against let's say the D7000 or it's true competitors the D300s and 7D, we need to give a noob the 3 dslrs and get him/her to take pics of birds in flight.
Let's say 100 shots from each dslr, then assess out of the 100 shots from each dslr how many in focus shots were made.
This of course could be done with any fast action photography.
Only then can could we really quantify which dslr has the edge in AF.
I have never in my life done BIF and really really struggled, lets say just about impossible with the Pentax 55-300 and the K10D.
Due to these experiences and a myriad of other problems the K5 was coming out with (and still is) as listed in this very forum I just could not take the risk of putting money into the K5.
So I did invest in the D7000 and the 70-300 and on my very first outing got this on a very very blustery day at the beach - I did not have to take 100 shots to get this. just one in fact - I put the Nikon in 3D tracking with 21 zone assist and let it does its job while I focused on composition.
With a little more practice birds in flight moving across the frame will I'm sure be more easily for a noob like me.
Please bear in mind the background which could have easily fooled lesser systems - so I'm more than happy.