Chu, Janet, authorHirschfeld, Sue, authorKelly, Venice, authorC.P. Gillette Museum of Arthropod Diversity, publisher2022-03-282022-03-282022-04-04https://hdl.handle.net/10217/234579April 4, 2022.Includes bibliographical references.The butterfly inventories continued for the 18th year in a few of the Boulder County Open Space properties. However, because of the Calwood Fire during October 17, 2020, two of the survey areas were inaccessible; Plumely Canyon and the work road through the streamlet near the Lichen Trail. Geer Watershed had been burned, but the meadows above the Resident Ranger's Cabin and associated streamlets were made accessible with our 2021 permit. Cabbage Whites (Pieris rapae), Orange Sulphurs (Colias eurytheme) and Common Wood-nymphs (Cercyonis pegala) were more numerous when compared to 2015-2020 populations before the burn. In 2021 within other Open Spaces, Anne U. White and Caribou, the resident species produced noticeably large populations: Julia Orangetips (Anthocharis julia), Pine Whites (Neophasia menapia), Northern Checkerspots (Chlosyne palla), Common Wood-nymphs, Small Wood-nymphs (C. oetus), Common Checkered-skippers (Burnsius communis). On the other hand, the well adapted non- native Cabbage Whites were again the most common during the long season; Variegated Fritillaries (Euptoieta claudia) and Dainty Sulphurs (Nathalis iole) were numerous flying in from colonies in the eastern plains and low foothills where their host plants were plentiful. 95 species were seen in 2021: 129 species between 2004 and 2021 in the county Open Spaces. 203 species are on the record for Boulder County (Butterflies and Moths of America 2021) website. The average number of species per year observed within the Open Spaces by this team is 88.born digitalreportsengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.Lepidoptera -- Colorado -- Boulder CountyButterflies -- Colorado -- Boulder CountyText