I think the answer can be found if you read his profile on Flicka - he's single! :)
This means that unlike many of us he has lots of time to engage his passion, get out in the field and do all the hard work that it takes to build up a portfolio like that.
To me, suggesting that it is down to a blind, bait or local zoo is a bit like putting it down to his having a "really good camera". The secret is skill, hard work and talent.
He also makes reference to using a kayak, so perhaps that assists in getting close to some of the shore birds, waders and herons, too.
I asked him where if the birds were captive and where he photographed them (specifically the kestrel). He said they were not captive and only told me the area where he found them (a large area by the way). When I asked for specifics, he simply did not respond to my message.
OK, one guy I know has found out where that kestrel is. He took a couple of shots of it yesterday. He said at one time the kestrel landed so close to him that he had to move back to take the shot. I'll go look for it !