Not gonna lie I only stopped feeling the need to crop my bird snaps in once I got to 800mm equivalent, but I fully acknowledge this is a skill/patience issue. Though I'll get lucky and have a bird come up close now and then, I suppose thay's what zooms are for.

>>4422855
For BIF you do need the reach but otherwise you can always do better, just wait for birds that are closer to the ground or find nearby hills to flatten the perspective. Look up Simon D'entremont on youtube, he has lots of practical tips like these.
>step ladder
You jest but pros will go to much further lengths.