Under permit from the Colorado State Park system, this program seeks to document butterfly populations in the diverse habitats of Colorado’s Roxborough State Park in Douglas County. Using a modified Pollard approach, a consistent 7.5 km path is walked on > 20 occasions during the butterfly season from towards the end of March through the beginning of October. Initially conducted mostly in the 1980s as presence/absence surveys, they were re-started in 2018 utilizing counts of species.
Roxborough State Park (Colorado)
Snapshot
Coordinator: Nelson, Mark
Program Started:
Institution Type: Academic Institution
Species Focus: All butterfly species
Contact: Mark Nelson (sigmarknelson@gmail.com)
Protocol
Protocol Type: Restricted search, Pollard, Transect
Data Type(s): Presence only, Abundance
Survey Focus: Adults
Protocol Notes: Surveying occurs while walking the same 7.5 km path used in the initial study. A portion of this sampling path is off-trail. The path was designed to cross ecotones and to sample the various habitats within the park. The walk is similar to a Pollard Walk (Pollard 1977); however, it is somewhat unconstrained. If butterflies are seen nectaring some distance from the walk, those are sampled. Because nectar can vary in space and time, this captures some of that variability. Some extensive grassland areas may also be crisscrossed to some degree in order to flush uncommon butterflies.
Additional Notes: Minimum temperature of 60 deg F is required at survey initiation. Time of start varies seasonally, with later times utilized early and potentially later in the season. While data on wind speed was collected, higher speeds were not considered a huge detriment for surveys. Geology of the area creates patches that differentially inhibit influence of high wind speeds. Weather data can be downloaded from the Colorado Climate Center (climate.colostate.edu/data_access.html) from a station located near the visitor’s center at Roxborough SP.
Taxonomic Standard: Modified Pelham 2013
Program Results
Publications:
Nelson, S.M. 2025. Observations on Aphrodite Fritillaries (Argynnis aphrodite) at Roxborough State Park, Colorado. Journal of the Lepidopterists’ Society In press.
Nelson, S.M., M.E. Epstein, & S. Heinz. 2023. Duskywings (Erynnis:Hesperiidae) of Roxborough State Park, Colorado USA: Possible weather and biotic effects on abundance 2018-2022. Journal of the Lepidopterists’ Society. 77(4):235-242
Nelson, S.M. 2020. A new confirmed state record for Erynnis tristis tatius (W.H. Edwards, 1883) in Colorado, USA. News Lepid. Soc. 62:44-45
Nelson, S.M., M.E. Epstein, & S. Heinz. 2020. Resiliency of the butterfly fauna at Roxborough State Park, Colorado: Long-term and short-term alterations in phenology and species presence. Journal of the Lepidopterists’ Society 74(4):244-256.
Nelson, S.M. & M.E. Epstein. 1998. Butterflies (Lepidoptera: Superfamilies Papilionoidea and Hesperioidea) of Roxborough State Park, Colorado: baseline inventory, community attributes, and monitoring plan. Environmental Mgt. 22:287-295.