I've had several questions recently about the Bambeco solitary bee house sold at Costco (they sell the Swiss Alps model), so I decided to head to my local store to check it out. While the price is amazing, the house has a few features that are not so ideal. For details on what makes a good solitary bee house, see here and here.
The Bambeco bee house sold at Costco
The nesting tubes are about 4.5 inches deep
Correctly built solitary bee nest. Note the variety of tube sizes and the holder's protective overhang.
The depth. At 4.5 inches deep, it is sufficiently deep to allow the production of female and male bees.
What's not so good:
The nesting tube diameter. While the variety of diameters is good, solitary bees need tubes from 3/16 to 5/16 in diameter. While other arthropods, such as spiders, may use the larger tubes, they will not be used by bees.
Limited protected overhang. The nesting tubes should be placed so that the entrance has a bit of protection. That's why we make our houses at least an inch longer than the tubes.
The nesting tubes are glued in place. Once a tube is used it should be replaced to help prevent the build up of pathogens.
March 13, 2019: winter update
The bee house is not holding up well to the winter weather. Here's a photo showing some superficial mold as well as separation of the sides from the base. Note that I added extra protection by attached redwood fence boards to increase the cover of the roof.
Weather damage to the Bambeco solitary bee house
March 27, 2019: comments on the 2019 model
I purchased the 2019 model today. The center blocks are an improvement; these are the correct size and should be used by bees. Purchase paper tubes (one example here) to line these so they can be correctly cleaned and re-used. The side tubes are mostly too large and cannot be removed once used. The top section is intended to be a butterfly house; unfortunately these wind up mostly housing spiders.
Bambeco bee house 2019 version
The instructions are mostly accurate as well. The first page gives a correct, if cartoonish, description of how the bee house works. Note that materials other than mud are used depending on the bee species.
The second page also has some good information. Points that need correcting are #2 (native plants are great but not required) and #6 (Tubes could be cleaned out with pipe cleaners and re-used a second year; after that I would discard them. To me, the best way to use this house would be to cover up the two side sections and place removable paper liners in the center.) The idea of rotating two bee houses is worth trying.
Update July 1, 2019
The Bambeco bee house shown above is not holding up well to the weather. After three months outside (there was one week of rain during this period), the paint on the roof is peeling.