>>3680316>>3680307Pretty much on the money regarding the distance, the background goes off into infinity focus hence the nice smear.
But it was still a fairly considerable crop, far from filling the frame.
I'd consider 250mm on APS-C to be perfectly fine for perched birds, especially if you're just sitting still and waiting.
As far as taking shots as you hike, I don't think you've got the adequate reach, even focusing is difficult since the AF point itself is as large as half the small bird involved.
