I heard one a few years ago by my cousin Gary and it goes like this. He had these bushes in his yard that produced these little berries that turned red when ripe, they hung from the bushes awhile then they fell off. Occasionally birds would land in these bushes and would eat the red berries.
One day Gary was laying on his couch and seen a few birds land on the limbs and were eating the berries then all of a sudden it looked like they fell to the ground. So he got up and sure enough they would be laying on the ground, some birds moved and some didn’t, he had never seen anything like this and he wondered what was going on and wondered if they were being posioned. He watched the birds and they came out of what condition they were in on the ground and flew off, he said they laid there for up too 10 minutes.
Concerned He got in contact with the local DNR and an officer came to his place. The officer looked at the bushes and said, Well I thought these would be the kind of bushes I thought they might be. Gary then said what are you talking about. The officer then said these bushes produce more sugars then most berries and when they ripen in the sun the sugars occasionally turn to alcohol. Gary said you’ve got to be kidding and the officer said no That he wasn’t kidding. He said what’s going on is the birds eat these sweet berries and then after they have had enough of them it does get them drunk and they do indeed get drunk and that’s why their falling off the limbs. They come around laying there on the ground and then they fly off. After that Gary every year watched his bushes more closely and sure enough it would occasionally happen, he said not every year but some years these berries produced more sugars then others,,,and occasionally drunken song birds.