Butterflies of the Colorado Front Range

Photographs, Species Accounts and Checklists

Welcome to Butterflies of the Colorado Front Range, a general guide to the butterflies of Colorado’s Front Range. This website brings together photographs, species accounts, and other information to help you identify and learn more about the butterflies found in this region.

Geographic Scope

The Colorado Front Range extends from the Colorado-Wyoming border south to Pueblo, and from the Continental Divide east to the plains, and includes the following counties: Larimer, Boulder, Broomfield, Gilpin, Clear Creek, Jefferson, Denver, Douglas, Park, Teller, El Paso, Fremont, and Pueblo.  Within this region are five major life zones: plains, foothills, montane, subalpine, and alpine.

Exploring the Butterflies

Butterflies are presented in general taxonomic order by family, genus, and species. Each species account includes field photographs and information about appearance, wingspan, habitat, host plants, and life cycle, including adult flight periods.

Flight periods are intended as general guidelines for the Front Range. They may vary with weather, elevation, host plant availability, and location along the north-south range of the region. The website also includes information on butterfly anatomy, conservation, a glossary of terms, and additional resources.

We hope this website helps you discover, identify, and enjoy the remarkable diversity of butterflies found along the Colorado Front Range.

Boulder County Nature Association (BCNA) is the host and sponsor of this website.

BUTTERFLIES IN BOULDER COUNTY

Butterfly Surveys have been completed on some Boulder County Open Space properties from 2002 to 2026 by Janet R. Chu and her butterfly research team.  Boulder County Parks and Open Space (BCPOS) and Boulder County Nature Association (BCNA) have encouraged and partially funded these important surveys with the resulting reports and analyses of trends. BCNA funded the 2007 continuation of a research program to survey Boulder County butterflies and the preparation of a 74-page report. The BCPOS Small Grants Program supported the surveys in 2004-2006.  Since then, monitoring of butterflies on Boulder County Open Space properties has been partially funded by the BCPOS and the BCNA Small Grants Programs. Links to later reports (PDF) on the Boulder County website are listed below.  

• Butterfly Research in Boulder County 2004 - 2007
• Butterflies A Continuing Study of Species and Populations In Boulder County Open Space Properties - 2011 Inventory and 2007-2011 Analyses
• Summary report of butterfly observations on the Anne U. White Trail in Boulder County before the September 2013 flood
• Additional Boulder County butterfly survey reports for the following years are published on the Boulder County website. (2002; 2003; 2004; 2005; 2006; 2008; 2009; 2010; 2011; 2013; 2018).

Butterfly Counts have been held at the Cal-Wood Education Center every July 4 for 42 years, 1984-2026. Cal-Wood is a registered nonprofit that connects children and adults to the Colorado mountains through environmental education, conservation, and recreation and is located near Jamestown, Colorado. A 29-page report on the Cal-Wood butterfly counts covering 1984 to 2014 is available as a PDF (3.8 MB).

• Cal-Wood Fourth of July Butterfly Counts, 1984-2014 

The field guides, Butterflies of the Colorado Front Range, 1^st and 2^nd editions, by Janet R. Chu and Stephen R. Jones, stem from research partially supported by the Boulder County Nature Association.