Prof. Rebecca (Becky) Irwin has been collecting data on the abundance and timing of bees in permanent sites near the Rocky Mountain Biological Lab (RMBL), Gothic, Colorado, USA, from 2009 to present. During the flight season, we use pan traps and netting every two weeks to estimate bee abundance by catch rate. All solitary bees are collected, pinned, and identified to the lowest taxonomic level possible (>75% of specimens to species). Bumble bees that are netted are identified in the field, marked and released. The dataset consists of >190 bee species from at least 36 genera. The pan trap and netting data are in two separate files. We also collect flowering data at the time of bee collection every two weeks. More detailed flowering data can be found in the Long-term flowering phenology and abundance project at the Open Science Framework (https://osf.io/jt4n5), and long-term weather records are available from the region as well from the RMBL (www.rmbl.org). The bee phenology and abundance data are available for research and teaching use if you request them. Go to the "Data use" component for details of our data use policy. If you would like to request specimens on loan, please email Becky directly.