I tried this once, with a fair amount of success.
One fall, I saw a flock at the other end of a field that had some "texture" to the edges (it wasn't a straight line). They were in the back corner from where I was, but I knew that an upright approach would never work. So I got on my hands and knees and started crawling towards them.
The first 40 yards or so was pretty easy crawling, but the last 60(ish) yds. would be the tricky part. I just kept thinking of how coyotes or bobcats would do it. At the right times (when one of them might be able to see me) I froze, and made painfully slow movements when I had to. Eventually, I got as close as I could with the little bit of cover that I had and they were moving towards the center of the field. So I tucked into the tall grass between the treeline and the field and waited. There was only about 20 yds. for them to cover before they would be within range and right in front of me.
As if they were following a script, they moseyed right to where they were supposed to. I went to raise my 62" Martin L-100 longbow and found that it made it to about 3/4 of the way to my shooting posture and stopped! I tried again to raise it the rest of the way but it wouldn't budge. I looked down to see that the tall grass had grabbed a hold of my limb and string and it was NOT letting go without some major movement. So I made the movement, they busted and the whole thing was over.
It was awesome to have gotten them that close (they were somewhere between 15 & 20 yds in front of me when I tried to shoot).