The Potomac Valley Audubon Society is sponsoring a Sept. 10 Natural History Workshop on aquatic macroinvertebrates, also known as “water canaries” from 9-11 a.m. in shallow water of Antietam Creek on the Antietam National Battlefield near Sharpsburg, Maryland. The workshop will be led by local naturalist Sandy Brown.

It is open to anyone with an interest. It will be a very family-friendly event, and children will be welcome if accompanied by an adult.

Space will be limited and pre-registration is required. To register and get directions go to the PVAS website at www.potomacaudubon.org.

There will be a fee of $15 for PVAS members and $20 for nonmembers. Children under18 may participate free.

Aquatic macroinvertebrates are small animals living among stones, logs, sediments and aquatic plants on the bottom of streams, rivers and lakes. They play an important role in fresh water ecosystems and are widely used as indicators of pollution when testing for water quality (hence, their nickname of “water canaries”).

Workshop participants will learn how to identify these organisms and how they indicate water quality.

Participants should dress for the weather, bring along drinking water, sunscreen and insect repellent, and be prepared to stand in ankle-deep water.

This event is one of a series of Natural History Workshops on different natural history topics the Society is sponsoring this year.

These workshops are intended for people who are interested in learning about particular natural history topics in considerable depth but cannot commit to pursue the much more comprehensive natural history education available through PVAS’s Potomac Valley Master Naturalist Program, which can take a year or more to complete.

For more information contact Krista Hawley at adultprograms@potomac audubon.org or 703-303-1026.