Dynamic specialization refers to the concept that animals do not have fixed niches, but that, instead, niches are malleable and dependent on the community composition of sympatric and competing species. My study examined dynamic specialization in a bee community near Flagstaff, Arizona, by assessing temporal and spatial changes in floral constancy, which might be driven by niche partitioning, resource availability and diet breadth. I found that bees do exhibit temporal and spatial dynamic specialization and that some bee species are more likely to collect randomly from local resources than other species. This bee community preferred certain species of flowers, notably in the Rosaceae, and disfavored others, such as those in the Fabaceae. All bee species caught were broadly polylectic, and this generalist community did not show niche partitioning. These findings have implications for the conservation of native bees in the U.S. southwest as they face threats from climate change, encroachment from non-native species and anthropogenic forest management.