Terry, Yes, there are designs of nest structures available. My reference material is rather limited but perhaps Chris Plowright at U. of Ottawa can provide more uptodate info. Also, Phil Torchio at U. of Utah may have quite a bit of info available of nest designs for non-Apis pollinators (not limited to bumbles). In addition to the actual placement of 'bait' nesting sites, undisturbed vegetation surrounding cranberry fields are equally valuable. Flooding, use of pesticides, clearing of vegetation, and other disruptive activities have been the primary causes for the quantitative decline and diversity of wild bee species. Paul van Westendorp [log in to unmask] Provincial Apiarist British Columbia