Radio tracking and volunteer surveys as a means to discover bumble bee nests

Bumble bees are highly efficient pollinators of both ecological and economic significance, yet are facing widespread decline. We have a good baseline understanding of bumble bee foraging needs, but huge knowledge gaps remain for nesting habitat. Researchers have effectively located nests using both visual surveys and radio tracking, but it is unclear which is a more efficient use of resources, since visual surveys are time consuming and radio tracking is expensive. To increase the efficiency of visual surveys, researchers at the University of Minnesota launched Bumble Bee Nest Quest, a participatory science program tracking bumble bee nesting. Our goals are to both increase knowledge of species specific nesting habitat preferences and compare the efficiency of visual surveys and radio tracking techniques for nest location. Volunteers conduct hour-long meandering surveys looking for signs of bumble bee nesting. We also use radio tracking to locate nests with small, ultralight tags. In 2024, we found six nests, all in prairie habitats, representing two different species. We conducted habitat assessments to document plant species, availability of bare ground and leaf litter, and soil qualities near nests and in surrounding areas. This combined methodology allowed us to produce a comparison of costs and benefits of visual surveys and radio tracking to enable efficient bumble bee nest discovery in subsequent projects. By collecting more data on bumble bee nesting habitat, we can better inform habitat restoration efforts, as protection of potential nesting sites will protect future generations of bumble bees.