For the second year in a row, I have had mason bees nesting in these tiny nesting cavities. These tiny cocoons are similar in colour as Osmia lignaria cocoons, but much smaller in size. I have not seen this small bee fly, so I do not know what they look like nor do I know what time of the year they appear. If you have a piece of corrugated plastic, set a piece in amongst your other nest materials and see what happens.
|Here is the Highrise with nesting trays (without the cedar roof). The gap above the nesting trays is where I insert the folded plastic corrugated material and use it as a wedge to securely hold trays in place.
|The spring mason bee cocoon is on the left (with its nesting trays on the far left). The tiny summer mason bee cocoon is on the right.
|After slicing the nesting tunnel open you can see how the tiny cocoon fits into the tiny nesting tunnel.
|Closeup of plastic corrugated sheets filled with mud plugs.