Beware! There are birds flying drunk these days.
No, they're not bellying up to some bird bar or avian saloon and drinking their way to intoxication. Instead, they're feasting on the fruits of the summer and getting intoxicated that way.
Just as the beer, wine and liquor-making process generates alcohol by fermenting fruits and grains, apples, crab apples and berries still hanging on bushes and trees can gradually ferment their own alcohol.
For birds who eat these fruits in fall and winter, it can be an intoxicating experience. And just like people who overindulge in alcohol, birds can begin to show signs of intoxication, too. They'll do things that they wouldn't do if they didn't have alcohol in their system, including running into things.
On a small scale, you'll sometimes see them teetering on branches or stumbling when they're walking. You might watch them bump into things when they fly.
But there have been some large-scale drunken disasters, too. Big buildings around the world have reported dozens and sometimes hundreds of birds that have crashed into their big windows, causing injury and death.
In this area, beware especially of the fruit-loving Bohemian waxwings, which are susceptible to intoxication because of their feeding habits. They often travel in sizable flocks. And there are no bird police cracking down on FWI (flying while intoxicated).