Coot
UFK and Bob are right on. First thing to do is avoid birdsnests by making sure your reel is adjusted right for what you're tossin. Second don't overfill your reel. My major pain is not birds nests right off the bat but that occasional d@mm overspool at the end of the cast that leaves a little loose line on the spool. If left there they will ultimately cause a birds nest and other problems.
Only solution is to let the line continue spooling off until you've cleared it and reel up the slack quickly. Pain in the butt when you've put your gear in the sweet spot.

gooose