Final Report An Inventory of Butterflies - Heil Valley Ranch Open Space 2002 - 2004 Caribou Ranch Open Space 2004 Boulder County Parks and Open Space Small Grants Program 2004 By Jan Chu, Catherine Cook and Donn Cook Table of Contents • Page I. Abstract I II. Introduction and Literature Review 2 Reference Literature 3 III. Materials and Methods 4 a. SurveyTimeline 4 b. Survey Procedure 4 c. Survey Habitats 5 IV. ResulL'i. with Detailed Analysis 6 V. Discussion of Ihe results. including how the resuhs apply 10 natural resource andlor visitor management 7 a. Weather 7 b. Overland Fi re 7 c. Buuerfly Populations 8 d. BUllerfly Checklist 9 c. Rare bUllerflies 9 r. Caterpillar Food Plants 10 • VI. Maps II VII. Conclusion II V III. Rccommcndations 12 IX. Acknowledgemcnts 13 X. Attachments I. "2004 Butterfly Survey for Heil Valley Ranch Open Spacc", Boulder County. CO 2. "2004 Butterfly Survey. Caribou Ranch Opcn Space", Boulder County. CO 3, Photographs 4, Brochure * Heil Valley Ranch BUHerflies 5. Map * Heil Valley Ranch Open Space 6, Map * Caribou Ranch Open Space 7, Slides (one copy provided to Boulder County Parks and Open Space) • I. Abstract This projcci included two primary purposes: • 1) Continue an invel1lory of bUlIcrflies on Heil Valley Ranch Open Space for the third summer season. and 2) Begin a new survey of butterflies on the Caribou Ranch Open Space. Field observations occurred in several different habilals. including pine forests. grasslands. willow bog. riparian. and disturbed areas (roads and trails). In addition to surveying bUlIcrflies. we look field nales of easily identified blooming flowers (neclar sources) and host plants (food sources for caterpillars). as well as interesting butterfly behavior. Heil Valley Ranch: Sixty species were observed from March 23 through August 12.2004. During the years 2002-2004. eighty-seven species were identified on Heil property. The spring and late sUlllmer-carly fall bUlIerOy populations seemed to be typical. Three years of sampling resulted in a list of the more common species in the form of a brochure, "Heil Valley Ranch· Butterflies:' Caribou Ranch: Thirty-seven species were seen at Caribou during the short season of June 29 through August • 5,2004. These were found on disturbed roadways. in sUlTOunding pine forests. agricultural land and near willow bogs. Additional surveys in future years may set a beller baseline for comparison of populations than this ye<.lr did. In Boulder County the number of recorded butterflies is about 192 species (Opler, 2004): therefore 45% of these were seen in Heil Valley Ranch during the years 2002 through 2004. About 19% of the total recorded Boulder County buuernies were observed on Caribou Ranch during the first survey year. Many of the county species typically inhabit the FOOlhills­ Montane zones: but others are found only on the prairies and at higher elevations. The Boulder County record includes seldom-observed migrant visitors also. The Open Space communities we studied were rich with diversity of species and habitats. BOlh Heil and Caribou are supporting vigorous habitats as shown by the numbers of bUllerOy species living in these Open Spaces or migrating into these areas for the summer. Further • surveys and research are needed to better understand the habitat needs of Boulder County • bUllernies. This information will help the Parks and Open Space Department make recommendations for protection of species in the years to come, whether by limiting human • use, haIling habitat destruction. or by other means. II. Introduction and literalure review The three primary members of the survey team are all volunteer naturalists for Boulder County Parks and Open Space. Allhough we are not trained lepidopterists. between the three of LIS we have over 40 years of butterfly study and fieldwork experience. We are interested in compiling surveys of the butterflies found on Boulder County Open Space properties to identify species. to understand their habitat requirements, 10 look at changes in populations (due to disturbance of habitat or changes in weather paucrns), to locate colonies of the rare bUllerOies. to record unusual population OuclUations, and to provide helpful information in order to assure the continuing survival of these butterOies. Throughout this region's history including use by prehistoric people. homesteaders. ranchers. farmers, and miners, Heil and Caribou have maintained a relatively undeveloped and natural selling. Both Heil and Caribou properties include rich and diverse habitats that support an • abundance of wildlife, both large and small. Allhough detailed plans are orten put in place to protect the vertebrates found on each Open Space property, such as birds. squirrels. prairie dogs, foxes. deer. elk. bobcats, black bears and mountain lions, the invertebrates in residence are orten overlooked. In order to protect the invertebrate butlernies specifically, it is important to idcntify thcir occurrence, locate and protect critical habitat areas from unnecessary forest thinning, prescribed burns. trails or other excessive use by the public. • 2 Reference literature: Beidleman. Linda H.. R. Beidleman. B. Willard. Pllims a/Rocky Moul/wi" National Park. 2000. • Rocky Mountain NalUre Association and Falcon Publishing. Inc. Brock. Jim and K. Kaufman. B/If/erjIies afNorth America. 20(H. Houghton Mifflin Company. New York. New York. Callahan. Bill. October Weather Review. Daily Camera. Nov. 2. 2()().l. Page 68. "Caribou Ranch Man:lgemenl Plan. Dmft:' Boulder County Parks and Open Space. September 2002. Chu. Janet. C. Cook. D. Cook. "An Inventory of BUllcrtlies at Heil Valley Ranch Open Space:' 2003. Unpublished. Boulder County Parks and Open Space. Boulder. Colorado. Glassberg. Jeffrey. Buuerflies ,hrough Binoculars. The Wesl. 2001. Oxford niversity Press. Inc. Nc" York. New York. GucnneL G. K. Guide to Colorado Wildflowers. Plaim lIfIll Foorhills. Volume I. 1995. Westcliffe Publishers. Inc.. EnglewoOO. Colorado. Guennel. G. K. Gl/ide to Colorado Wildflowers. MOl/mains. Volume 2. 1995. Westcliffe Publishers. Inc.. Englewood. Colomdo. Kershaw. Linda. A. MacKinnon. and J. Pojar. Pltmrs ofrhe Rocky Mou",oins. 1998. Lone Pine Publishing. Edmonton. AB. Canada and Auburn. Washington. Krishnan. Sarada. Bllflerfly Gardening -A Guidefor Colorado G(mleners. 2003. Butterfly Pavilion. • Westminster. Colorado. "North Foothills Open Space Managemenl Plan. Draft.'· Boulder County Parks and Open Space. 1996. Opler. Paul A. A Field Guide to Western B//lferflies. 1999. Houghton Mifflin Company. Boston. New York. Opler. Paul A.. R. Stanford. H. Pavulaan. coordinators and editors. "Boulder County Butlerllics.'· 2004. N0l1hern Prairie Wildlife Research Center, htlp:llwww.npwrc.usgs.gov/reStlllt"cc/dislr/lepidlbnyusa/checklist Opler. P.A.. A.D. Warren. Scie",ijic Name.\·for BlIrrerfly Species ofNorr" America. nor/II ofMexico. as updated on February 14.2003. Pesman. M. Walter. Mee/ the Natives. Tenth Edilion. 1992. Denver BOlanical Gardens. Inc. Roberts Rinehart Publishers. Lanham. Maryland. Pyle. Roben Michel. Audubon Society Field G/lide f() Non/l Americtl1l BUflerflies. 1981. Alfred A. Knopf. lew York. Robenson. Leigh. Southern Rocky MOItJlfaill Wildflowers. 1999. Falcon Publishing. Inc. Helena. Monlana. Simonson. Sara and P. Pineda. "Field Survey of Boulder County Open Space. Hall and Heil Ranches." • 1995. Research sponsored by Natural Heritage Program. 3 III. M3teri~lls and Methods Used Survey Timelinc: • The 2004 plan was to conduct field studies biweekly. at Heil one week and Caribou the next. However. a delay in the date of access 10 Caribou due to restrictions related to elk calving changed thai plan. June and July were cold. wet and cloudy months. which also reduced our Sighting days and numbers of individuals. Different habitats within each Open Space were visited periodically. The field period for Heil Valley was from March 23 to August 12: Caribou June 29 10 August 5. Heil Valley Ranch: Observations began before the snow had disappeared. to observe some of the over-wintering and early spring bULlerflies. On thaI first field day we observed hoary commn (Po!ygollia graci/is). mourning cloak (Nymphalis wl1;opa). milben's tonoiseshell (N. milberri) and the always-present cabbage white (Pieris rapae). waking from their winter's dormancy to enjoy the mild temperature. On April 15 the common roadside-skipper (Amblyscirres llialis). the only one sighted in three years. and the Sheridan's hairstreak (ClIlJophrys sheridanii). the earliest emergent bunerny in the Foothills. were observed. During this summer, the greatest number of western pine elfin (c. eryplwlI. was also sighted • on thaI day. It was fonunate we began the season early this year. as Ray Stanford suggested. In spite of the wet, cool weather, we visited Heil Valley Ranch nine times during 2004. The final observation at Heil was August 12. Caribou Ranch: An inventory of butterflies began on June 29, 2004, the day we were permitted to enter the area. following closures for elk calving. Two additional days for observ.uions occurred in July and August. Survey Procedure: This survey was not executed using traditional scientific protocol or to a restricted specified area. but was made by more casual observations. As butterflies were sighted. they were identified using close-focusing binoculars or a net and release procedure. The species and numbers (clearly identified at close range) were listed on the enclosed charts. Records include the date, and lime in the field, temperature. general