Shifting Mason Bees from Existing Blocks to New Nesting Houses

Overview principle

Most mason bees want to see the hole they are placing pollen in.  If they can’t see the hole, they typically won’t go to it.  We want to hide the old holes, but allow the mason bees to exit them.

Transfer procedure

Hide the old holes:  Place your wood block in a cardboard box or paper sack with means for the mason bee to exit.  Cut a few half inch holes on each side.  Close the box/sack.

Allow the mason bees to exit:  Ensure that there is space between the box/sack and the holes the mason bees are exiting in the wood block.  The mason bees will now exit the wood block and crawl out the hole in the box/sack.

Placement of the box/sack:  Place the box/sack near the new nesting house.  If possible, place the box/sack on top of the nesting house, tied underneath or nearby.  We suggest that it should be off the ground to prevent drowning of the mason bees.

Break-apart block?  If you have a break-apart block, we suggest that you take the block apart and place everything into a paper sack with holes in it.  Don’t worry about the pollen mites, dirt, or debris. 

Leave this block/sack up until early May.  Then remove the block from the yard to prevent its reuse.