I'd agree with the majority - it's totally dependent on the circumstances. The biggest factorsare foliage, flock size, lightand sight lines.

If youget 10-15 birds roosted together, it's a little more difficult to slip in undetected - 30 eyeballs with 270 degree eagle vision really hurts your chances. Even harder if the leaves are still in bud, and the woods are wide open.

You can close in to 50 yards if there's a land formation in the way, so you've got to be perceptive of the bird's roost location, and where his sight lines are at.

Light - if it's pitch black, I'm not afraid to walk right past my tom to get into position. But, after stopping at the gas station, tuning the calls in the car, hitting that snooze button a few extra times - you're usually slipping in just as it's cracking daylight. The lighter it gets, the bigger radius you have to keep.