| | Acc. No. | Year | Location | County | Observers |
| 1918-001 | 1918 |
Near Masters
| Weld | Unknown |
| 1918-002 | 1918 |
Simpson
| Washington | Unknown |
| 2003-113 | 1920 |
Akron
| Washington | Denver Museum of Nature & Science |
| 2010-055 | 1967 |
Red Lion State Wildlife Area
| Sedgwick | CSU |
| 28-73-120 | 1971 |
Lake San Isabel
| Custer | Donna Bregenzer |
| 28-74-3 | 1973 |
Columbine West
| Jefferson | Carolyn Spengler |
| 28-74-1 | 1974 |
SW of Denver
| Jefferson | Bertha Durfee |
| 28-74-176 | 1974 |
Virginia Dale
| Larimer | William Shuster |
| 28-75-69 | 1975 |
4.6 miles west of Crook
| Logan | Steve Larson |
| 28-93-28 | 1993 |
Pawnee Buttes and Pawnee N. Grassland (E. section)
| Weld | David Bolton |
| 2003-150 | 1998 |
North of Gilcrest
| Weld | Salvaged by W.G. Alther |
| 1998-078 | 1998 |
Wiley Pond
| Prowers | Janeal Thompson, Ken Giesen, Mark Janos |
| 2000-080 | 2000 |
Pawnee Buttes and Pawnee N. Grassland (E. section)
| Weld | Rachel Kolokoff, Bill Lisowsky, Larry Semo |
| 2002-013 | 2002 |
Blue Lake (Adobe Creek Reservoir)
| Bent | Duane Nelson, Brandon Percival |
| 2002-006 | 2002 |
Greeley
| Weld | Rachel Kolokiff, Roger Linfield, Ann Molison, Debra Sparn, Joan Glabach, Donna Emmons, Tamie Bulow, Paula Hansley |
| 2002-999 | 2002 |
CR 25 3 mls N of Hwy 266
| Otero | Larry Semo |
| 2007-020 | 2007 |
Blue Lake (Adobe Creek Reservoir)
| Bent & Kiowa | Bill Maynard, Brandon Percival |
| 2010-005 | 2010 |
Peyton
| El Paso | Brandon Percival, Bill Schmoker, Cole Wild, Snook Cippoletti |
| 2011-178 | 2011 |
CR 44 0.5mi W of CR 33
| Logan | Kathy Mihm Dunning, Bill Kaempfer |
| 2011-181 | 2011 |
Aurora Reservoir
| Arapahoe | John Drummond |
| 2012-002 | 2012 |
Jumbo Reservoir State Wildlife Area
| Logan | Bill Kaempfer |
| 2012-005 | 2012 |
Barr Lake State Park
| Adams | Doug Faulkner, Norm Lewis, Steve Mlodinow, Steve Walters |
| 2012-044 | 2012 |
Barr Lake State Park
| Adams | Doug Faulkner, Tony Leukering, Kay Niyo |
| 2012-043 | 2012 |
12 Rd N of LL Rd
| Prowers | Tony Leukering, Jane Stulp |
| 2012-070 | 2012 |
26.5 Rd S of Hwy 50
| Bent | Jane Stulp |
| 2012-014 | 2012 |
Pawnee National Grasslands (western section)
| Weld | Thomas Hall |
| 2012-033 | 2012 |
Red Lion State Wildlife Area
| Logan | Steve Mlodinow |
| 2012-034 | 2012 |
near Prospect Valley
| Weld | Steve Mlodinow, Bill Schmoker |
| 2012-037 | 2012 |
I-70 W of Bovina
| Lincoln | Robert Martinez |
| 2014-032 | 2014 |
W of Punkin Center
| Lincoln | Joey Kellner, Kathy Mihm Dunning |
| 2015-138 | 2015 |
114th and Tussville Rd
| Adams | William Hutchinson |
| 2017-070 | 2017 |
Fort Morgan
| Morgan | David Dowell |
| 2017-074 | 2017 |
NW of Fort Morgan
| Morgan | Mark Amershek |
| 2017-076 | 2017 |
I-76 mile 130
| Logan | Paul Sweet |
| 2018-028 | 2018 |
Pueblo Reservoir area
| Pueblo | Bill Maynard |
| 2018-031 | 2018 |
Boulder Reservoir
| Boulder | Peter R. Gent |
| 2021-013 | 2021 |
I-76 E of Prewitt Res
| Washington | Phil Lyon |
| 2022-005 | 2022 |
Pawnee National Grasslands (western section)
| Weld | Adrian Lakin |