The Butterfly Pavilion in Westminster, Colo., recently released the 9th Annual Colorado Butterfly Monitoring Network (CBMN) Report on the state of Colorado native butterfly populations, revealing heightened sightings and reporting of monarch butterflies throughout Colorado.
CBMN, celebrating its 10th year of consecutive monitoring in 2022, is a long-term community science project relying on volunteer monitors to record and identify butterflies throughout Colorado. The report suggests that 2021 was the best year in the past decade for monarch butterflies in the state, which is consistent with the increased monarch sightings across North America this past year.
“We are enthused to find that monarchs in Colorado showed an approximate 180 percent increase from the mean over the past seven years of our monitoring efforts,” said Shiran Hershcovich, Lepidopterist manager, Butterfly Pavilion. “The results are promising with the 2021 CBMN field season seeing a return of butterfly, monitor, and survey numbers higher than those in 2019.”
Since its inception in 2013, CBMN, the nation’s fastest-growing butterfly monitoring program, has recorded 107,811 individual butterflies and logged 3,166 butterfly surveys, accounting for 3,795 hours of volunteer monitoring through 2021. This past year included 12 counties including Adams, Arapahoe, Boulder, Broomfield, Douglas, El Paso, Gilpin, Jefferson, Larimer, Ouray, Routt, and Weld.
In 2021, all categories saw improvement from 2019 numbers and two categories set new high records: the hours spent monitoring and the number of surveys submitted.
Monitors observed and reported Monarch butterflies in all but two monitoring counties (Gilpin and El Paso) this season, with a count of 124 placing the species into the Top 25 Butterfly Species seen for the first time since CBMN was established.
Between 2014 and 2020, monitors observed and recorded an average of 44.3 monarchs each year. In 2021, monitors recorded 124 monarchs, roughly a 180 percent increase from the mean over the past seven years of monitoring.
Monitors observed and reported 120 total unique, identifiable species among all counties surveyed this season. Jefferson County exhibited the highest number of species seen, likely because of the county being home to the largest number of monitors, routes, and surveys submitted.
The 2021 CBMN field season experienced a return to numbers comparable to the 2019 field season across all categories evaluated. The decline in numbers seen in 2020 was likely attributed to the record-setting wildfire season in Colorado that impeded butterfly populations and outdoor activities, and the ongoing, global COVID-19 pandemic impacted volunteer participation.
“While we’ve got a lot of great data, we still need more,” said Hershcovich. “That’s where the public comes in with community science programs, such as our monitoring networks at Butterfly Pavilion, to cover more geographies and support pollinator conservation.”
The CBMN involves trained volunteer monitors walking the same route at least six times throughout the butterfly monitoring season (here defined as 15 May – 15 October 2021) and recording every butterfly seen in a six-meter radius.
During a survey, only one monitor observes butterflies at a time, however monitors are advised to work in pairs, allowing one to conduct the survey while the other keeps notes and aids with identifications. At the beginning and end of each monitoring session, monitors record the time, the temperature, the cloud cover conditions (clear, mostly clear, partly cloudy, mostly cloudy, overcast, or hazy) and the wind conditions (calm, relatively still, moderately windy, wind, or very windy). The monitors then walk the route at a steady pace, recording every butterfly seen inside their area of choice within their community.
The Colorado Butterfly Monitoring Network (CBMN) is a community science project led by Butterfly Pavilion that harnesses the power of volunteers to conserve Colorado butterflies. Butterflies are not only beautiful, but they also play a vital role in the ecosystem. CBMN data informs us on which butterflies are active in our state, giving us important insight on the health of our local ecosystems. CBMN volunteers observe and count butterflies in open spaces and parks multiple times per season, gathering essential data that land managers can use when making conservation decisions. It’s a fantastic chance to get outdoors and learn about butterflies, while having a positive impact on conservation in Colorado.
Photos credit: ©Butterfly Pavilion