August 2026 Newsletter

Can you believe it’s already August? We hope you’ve been staying dry through all of this rain…

Birding at the Quarries – Free Event

To start, we’d like to invite you to learn about native birds with us for a free birding event on Sunday, September 13th, 2026! Alyssa Syzmanski, Naturalist, will be leading the discussion at the TWWT Nature Education Center. After the classroom portion of the event, we will go on a walk around the Quarries to apply our new knowledge and look for birds. The event will run from ~10AM to 12PM.

We should be able to find a good mix of species – the variety of ecosystems at the HQRA attracts a diverse crowd, and it'll still be early enough that migrating birds haven't all left... In fact, September is the middle of peak migration season! We might see birds who are about to leave for, or are in the process of, their annual migration routes.

eDNA Survey Results

We recently performed a handful of eDNA (environmental DNA) tests in Great Lakes Quarry and Icebox Quarry to learn more about our aquatic neighbors. All living organisms leave traces of DNA in the environment as they go about their lives. As such, we can take samples (in this case, specially prepared syringes of water taken from the two lakes) and send them to a laboratory for analysis! While they do not cover 100% of species, eDNA tests provide substantial insights into ecosystems and the organisms within. We measured phytoplankton and fish in our survey.

In terms of the data collected, the two water bodies had notably distinct signatures. For example, ~66% of the DNA reads measured in Great Lakes Quarry was attributed to gizzard shad, a filter-feeding forage fish typically stocked as a bait fish. Bass (largemouth bass and other unresolved bass species) only made up 1.28% of reads. In comparison, Icebox Quarry had zero hits for gizzard shad, instead being dominated by various bluegill (35.1%) and other sunfish (44.5%). While these percentages do not directly correlate with population (i.e. you cannot conclude that 66% of all fish in Great Lakes Quarry are definitely gizzard shad, or that only 1.28% of all fish are bass), the ratios of DNA are helpful metrics to determine relative compositions. In our case, it is abundantly clear that bass populations are significantly limited relative to other species like bluegill or shad. This aligns with other surveys performed in the waterbody (electroshock fishing surveys and point surveys using catch data). Reversal of this trend is possible, but will take time and targeted effort.

If you want to help balance our fish populations, the best way is to harvest fish (within legal creel limits), especially when catching invasive species like common carp or “weedy” species like black crappie. While the ethics are sound, the popularity of catch-and-release fishing can actually cause ecological harm in the long term. Predation is a critical part of population balancing, but predatory species alone can only do so much. Based on what we’ve seen from our surveys and advice from the Illinois Department of Natural Resources Fisheries, we need to be harvesting thousands of fish from our lakes annually. If you catch a carp, bullhead, crappie, warmouth, or shad, it should always get removed from the waterbody.