"Creek Creatures" is this week's Summer at Crossroads series. This time of year, the creatures of the creek, wetlands and ponds are active over, under and on the water's surface, making them among our most popular attractions.

Naturally, we love our birds and fish, but learners of all ages also are fascinated by macroinvertebrates — creatures without backbones that can be seen without magnification. They are fascinating, and they are important indicators of stream health.

The week starts with a tale. At 2 p.m. Monday, June 29, Door County Librarian Beth Lokken will read the storybook "Over and Under the Pond" by Kate Messner, with art by Christopher Silas Neal. For those who cannot make story time, the pages of this book will be posted on our Trail Tales storybook walk, which starts at our West Trailhead.

Journeys with Joan, our weekly family program, will explore Great Lakes fisheries at 1 p.m. Tuesday, June 30, and hikers participating in Wandering Wednesday will surely observe creatures above, below and at the surface of Big Creek and our ponds.

For our 2 p.m. Thursday Talk, our presenter will be Gretchen Recupero Schmelzer, who is part of the DNR Water Action Volunteers program. She will explain how creek creatures are used as indicators to evaluate the health of a creek — perhaps even better indicators than occasional chemical tests.

Throughout the week, and for the rest of the summer, kids participating in Boys & Girls Club camps and Doorway to Learning will probably be knee-deep in the water, trying to capture — and release unharmed — creek creatures. All of them are unique and fascinating, though the "fan favorite creature" often is the amazing whirligig beetle, which kids discover is not easy to capture.

These incredibly fast macroinvertebrates live at the boundary above and below the water's surface. As their name suggests, whirligigs tend to gather in clusters and spin around in tight circles, very nearly — but never quite — colliding with each other.

These insects have divided eyes, enabling them to look over and under the water simultaneously. They also are hypersensitive to vibrations, so they never crash into each other. They are aware of struggling prey that drops into the water from above and insects or predators swimming below.

When they want to feed on dead creatures on the creek bottom, they trap a bubble under their wings, enabling them to stay underwater for a considerable time.

For protection, they give off a defensive scent to deter predators, though a few local species smell like green apples.

Perhaps their best protection is that even the slightest vibration alerts them to danger from above.

Researchers suspect they can detect wing vibrations and evade flying bats. Participants in our July 2 Nighttime Bat Hike at the Ida Bay Preserve will not be able to sense flapping wings, but hike leaders will have special equipment to detect the calls of these beneficial mammals. Reservations are required for this free event. Visit www.crossroadsatbigcreek.org to sign up.

Thanks to the generosity of our donors, Crossroads trails are open all day, every day, free of charge.

Monday, June 29

2 p.m. Tale: "Over and Under the Pond"

Join Door County Librarian Beth Lokken as she reads the weekly tale, "Over and Under the Pond," written by Kate Messner and illustrated by Christopher Silas Neal. It describes a secret underwater world brought to life.

These secrets, and many others, are waiting to be discovered over and under the pond in this charming children's book, which offers kids a peek into hidden ecosystems. Free and open to the public. Meet in front of the Collins Learning Center, Crossroads at Big Creek, 2041 Michigan St., Sturgeon Bay.

Tuesday, June 30

1 p.m. Journeys with Joan: Great Lakes Fisheries

Join naturalist Joan Wilkie for free, family-oriented activities exploring nature. Discover the wonders of our amazing Great Lakes fisheries. Suitable for all ages. Registration is not required. Free and open to the public. Meet at the Collins Learning Center, Crossroads at Big Creek, 2041 Michigan St., Sturgeon Bay.

Wednesday, July 1

1:30 p.m. Wandering Wednesday

Join a naturalist-led hike. Easy walking. About an hour. Well-behaved dogs are allowed on leash. Registration is not required. Open to the public and free. Meet at the Collins Learning Center, Crossroads at Big Creek, 2041 Michigan St., Sturgeon Bay.

Thursday, July 2

2 p.m. Talk: Creek Creatures

Take a closer look at the tiny creatures that tell big stories about water quality. Join Gretchen Recupero Schmelzer, a dedicated Water Action Volunteer, for an eye-opening exploration of stream macroinvertebrates — the insects, crustaceans and other small aquatic organisms that live in our creeks.

These "creek macros" are powerful indicators of stream health. Gretchen will introduce participants to the amazing diversity of macroinvertebrates found in Door County waterways, explain how scientists use them to assess water quality, and share what their presence, or absence, can reveal about pollution, habitat conditions and the overall well-being of our freshwater ecosystems.

Expect a fun mix of hands-on discovery and engaging science. Free and open to the public. Meet at the Collins Learning Center, Crossroads at Big Creek, 2041 Michigan St., Sturgeon Bay.

8:30 p.m. Nighttime Bat Hike

Using special sound recording equipment, hikers will be able to locate bats, and hike leaders will identify the species of bats at the Ida Bay Preserve this summer. Dress for the weather and bring bug spray. Space is limited, so reservations are required. Visit www.crossroadsatbigcreek.org to reserve a spot. Meet at the parking lot of the Ida Bay Preserve, 1195 Canal Road, Sturgeon Bay.