Nature Notes – Fireflies are wonders of summer nights

By Jim Gilbert

Fireflies in Carver County have been on the wing since June 10 this year.

The common names firefly and lightningbug are used for insects that communicate with pulsating “taillights” – segments at the ends of their abdomens with which these small animals are able to produce light by a chemical reaction controlled by the supply of air entering through minute openings. There are 136 species of beetles known as fireflies in eastern North America.

Here in Minnesota, north to south, the prime time to see these little specks of light, far into the night, is mid-June through July. Wetlands, wet ditches, tall grassy spots, old fields, forest edges, and sometimes lawns near more natural areas are good places to observe them.

The flashing is a recognition signal enabling the sexes to find each other. Each firefly species has a characteristic flashing rhythm. Typically a male emits flashes of yellowish light at intervals of a few seconds while he flies between a few feet from the ground and tree top level. Females wait on top of lower vegetation and if a flashing male of her species comes within about 6 feet she flashes back.

The exact number of seconds between flashes serves to distinguish the species. When fireflies perform their amazing act of lighting up, they give a special magic to warm summer nights. Sometimes an entire field, lawn or forest edge will be twinkling with hundreds of these little “lanterns.”


What’s happening outdoors now?

Our Waconia area yard received 4.85 inches of rain on June 19. From the looks of ponds in farm fields and stories of flooded basements, other parts of Carver County received 4 to 5 inches or maybe more.

June is rose month, when we can see the most blossoms from many types of roses including wild ones. It’s the combination of elegance and charm that has made roses as a group the best-known and most popular ornamental plant in the world. Also at this time, blooming northern catalpa trees and Japanese tree lilacs add much interest to our yards and neighborhoods.

Baltimore oriole, chipping sparrow, house wren and northern cardinal young are leaving their nests. Warbling vireos and mourning doves enchant us with their vocalizations. A trained listener can pick out two dozen or more different bird species in a June morning chorus of singers.

Waterfowl are mostly all in a flightless condition as they are currently molting their flight feathers. Placing two or three pennies in a birdbath will help reduce algae growth.


On June 26 a year ago

We had a mostly sunny, humid day with a high of 89 and a low of 73 degrees F. Honey bees were busy visiting lawn patches of blooming white clover. Northern catalpa trees were blooming and very showy.