
Participants using a Magiscope to look at macros.
Photo by Amy Ulland
As part of the Loudoun County Public Library’s Summer Reading Program, the Creek Critters of the Catoctin program held at the Purcellville Library on July 7 attracted 45 children and adults. Amy Ulland, Loudoun Wildlife’s Stream Monitoring Program Coordinator, kicked off the event by presenting some of the adaptations of benthic macroinvertebrates (often called “macros”) commonly seen in Loudoun streams.
Then participants observed some of these living macros, including a mayfly, cranefly, crayfish and riffle beetle among others, up close under Magiscopes. Watching the plump cranefly larva move and seeing the gills on the mayfly flutter were crowd favorites.
Participants also tried their hands at a simulated stream survey by sorting life-sized color drawings of a variety of macros off a collection net and into separate sections of an ice cube tray. Some used dichotomous keys to identify the critters, while others preferred using the Virginia Save Our Streams identification guide.
Markers and Playdough provided the perfect mediums for the children to apply their newfound knowledge of adaptions by creating their own macros.

Children enjoyed creating their own macros.
Photo by Emma Lloyd