We have had several hummers unwillingly take up residence in our garage
over the years. At first, I, like you grocery manager, was befuddled.
Actually, I was more than befuddled. I was beside myself!

Having all the doors and windows open didn't seem to make a
difference, because they naturally want to go up to escape, and "up" meant hanging
around in the rafters and ignoring the wide-open doors entirely.

So we closed all doors save one - a regular doorway, not a garage door
- and hung a feed about 6 feet above the floor and as close to that open
door as possible. Then I went in the house and had some alcohol to calm my
nerves, and by the time I got back out to the garage, it was gone.

That's obviously more difficult to do with a business using automatic
doors, but at the very least, I would think that they could hang some
feeders *somewhere*, then at least the hummers would have sustenance until they
calm down enough to escape.

Pat, in Newcastle