i bought a hive that had a lid made out of a piece of 3/4 plywood with a hole drilled to the side and a 1/2 hole on the edge. looks like its wax coated.. looks simple enough to make.. are they common? whats the holes for?
The 3/4 hole is for an inverted bucket feeder, pretty common down here. The lip on the bucket holds it up high enough for the bees to get to the feeder holes. Don't know about the notch. Some have a front and rear lip, usually called a migratory cover.