This is a good opportunity for some June vignettes from the natural world:

• Birds and mammals are among the few animal species that care for their young.

In fact, 99% of the million-plus species of the animal world simply give birth or lay their eggs and move on. Turtles, toads, frogs, wood ticks, mosquitoes and butterflies are some examples of animals that do not look after their young.

• Go jump in the lake! In June a good share of Minnesota’s lakes finally reach a surface temperature of 70 degrees or a bit warmer. Seventy degrees is the cutoff point for safe swimming; at lower temperatures a swimmer cannot usually exercise enough to maintain a normal body temperature and, so, would be subject to hypothermia.

• Minnesota is home to about 15 species of fireflies. Between now and mid-July is a great time to show young people this wonder of nature. From a half-hour after sunset and far into the night we can see these moving specks of light from southern Minnesota to the Canadian border and beyond. I like to check wetlands, wet ditches, tall grassy spots, old fields, forest edges and lawns near more natural areas for nature’s show of tiny lights.

• June is the prime month for Minnesota’s 20-plus nest bird species. Agassiz National Wildlife Refuge in northwest Minnesota may be the richest bird-breeding site in the Upper Midwest, with close to 140 species of nesting birds.

• Many of us enjoy watching ruby-throated hummingbirds feeding from nectar-producing garden plants and backyard feeders containing sweetened water. Hang up a feeder that is partly red, and make your own sugar-water solution using four parts water to one part white sugar. You do not need to boil the mixture, but hot water does help to dissolve sugar. Don’t use red dye. Many experts think the dye may be harmful to the birds. If the feeders are not emptied by feeding hummers, the sugar water should be changed every few days, especially in hot weather. If the sugar water solution turns cloudy or you can see black mold, wash the feeder in a weak bleach-and-water solution and rinse well.

• Adult Canada geese are particularly vulnerable now as they molt, lose their flight feathers and are grounded. Other waterfowl also are mostly all in a flightless condition. Look for the first Canada geese to be airborne around July 20, when you will see adults and their offspring from this year flying together.

Jim Gilbert’s observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.