BioBlitz finds nearly 700 species at the Dixon Refuge

On June 13 and 14, TWI held its first-ever “BioBlitz” to survey biodiversity at the Dixon Waterfowl Refuge at Hennepin & Hopper Lakes in north-central Illinois. Guided by more than 30 scientists and expert leaders from across the state, participants recorded 675 species at the site over a 24-hour period, including many that were previously unknown at the Refuge or unusual for the area.

“We knew a fair amount about certain groups of organisms that are found at the Refuge, such as birds and plants, but we knew very little about the presence of other groups such as fungi and most insects,” said Gary Sullivan, TWI’s senior ecologist. “With so many people out there searching, the BioBlitz helped us gain a huge amount of knowledge about the Refuge’s biodiversity in a short period of time.”

A six-foot-long bull snake found by herpetologists was one of nearly 700 species found during the Dixon Waterfowl Refuge's first-ever BioBlitz event.

The 3,000-acre restoration site was divided into targeted areas to cover, and most surveys were organized by organism group. Armed with species checklists, cameras, maps, and plenty of water and sunscreen, groups traveled by canoe, all-terrain vehicle, or on foot to find and identify as many species as possible. In total, 25 group forays searched for plants, fungi, birds, reptiles and amphibians, butterflies and dragonflies, other insects, and more. Volunteer photographers in each group documented many of the finds. 

Special discoveries during the BioBlitz included:

  • A six-foot-long bull snake and three milk snakes (an uncommon species), among 18 species of reptiles and amphibians found by herpetologists.
  • Two species of dragonflies/damselflies and two species of butterflies not previously known to be at the Dixon Waterfowl Refuge, including the emerald spreadwing damselfly and the northern broken-dash butterfly.
  • More than 50 species of fungi in wooded areas, many more than mycologists expected to find.
  • 12 species of bees, ranging from the brown-belted bumble bee to the flat-tailed leaf-cutter bee.
  • A healthy range of fish species, including a two-foot-long spotted gar and state-listed native fishes like redspotted sunfish and starhead topminnow.

Anna Braum (left) of the Chicago Botanic Garden and Cori Morse work to identify a plant species at Hickory Hollow during the BioBlitz.

Even though TWI already had more than 600 plant species and 270 bird species on its Refuge lists, there were surprises in these categories too. Plant surveys found 19 species new to the site, many of them at Hickory Hollow, the new 283-acre tract recently added to the Dixon Refuge. A state-endangered King Rail (a secretive marsh bird) and a Common Loon, rarely seen in Illinois in summer, caused excitement when they were spotted near base camp. Among 108 bird species found, eight were not known to be at the Refuge in summer, including Lesser Scaup, Bell’s Vireo, Brown Creeper, and Yellow-breasted Chat.

Check out the species lists from the BioBlitz here.

For participants, it was an eye-opening experience. “I enjoyed seeing all the wildlife that, despite me having lived in the area my whole life, I had never before seen and meeting and networking with all the biology and ecology professionals,” said one citizen scientist.

Experts that assisted with the BioBlitz represented many regional scientific and academic institutions, including Chicago Botanic Garden, Eastern Illinois University, Chicago’s Field Museum, Illinois Audubon Society, Illinois Department of Natural Resources, Illinois Natural History Survey, Illinois Ornithological Society, Illinois Valley Community College in Oglesby, McHenry County Conservation District, National Park Service, Peoria Audubon Society, Peoria Academy of Science, Trine University in Indiana, and Triton College in River Grove.

Thank you to all the expert leaders and citizen scientists who helped make this first BioBlitz a success! Please email Vera at if you recorded a species during the BioBlitz that’s not on our list.