update - trapped birds are free
Good News, the Hummers (>50) are out. Thanks to everyone for their suggestions. For some reason, moving the feeders around in the building, closer to the door and then actually hanging from the door did not work. This just attracted more outside birds and enticed them to come inside. A biologist at the MS Museum of Natural Science, after collaborating with his colleagues, recommended finding a way to hang a feeder just outside the door but away from the building and just low enough for the hummers to see from inside at the top of the building where they were flying. Also, placement was preferable with the sky as a background and with the sun shining on the feeder. I was able to accomplish this by parking my tractor that has a grapple on the front end and wedging a slender 19 foot extension pole within the grapple and hang the feeder from a hook on the end of the pole. The feeder ended up being approximately 4 foot from the building and 15 foot high. The door is 16 foot wide and 16 foot high. I took all of the other feeders out of the building so this was the only feeder available to them. No sooner than I had this feeder in place, approximately 10 birds came out to explore and ended up flying away from the building. This occurred several times over the course of the next hour until only 4 stragglers were left. I contemplated closing the door at that point but decided to give them some more time. It took another hour but the count went from 4 to 3 then to 2 and finally 1. I decided to wait the last one out and finally after another 30 minutes or so an outside bird came to the feeder and the last one left the building to join him. Now the door is closed and will remain so until migration has ended. The actual total count of birds that were trapped was greater than 50. If this had not worked, I had already contacted a contractor about taking off a couple of roof panels with insulation. However, they were highly discouraging this action.