Few of nature’s early spring events are more thrilling to behold than a V-formation of Canada geese, heading north, flying at speeds of up to 45 miles per hour, honking to communicate with each other.

Waterways start to open up when average temperatures reach 35 degrees for several days running, and Canada geese follow that 35 degree isotherm. In southern Minnesota we look for V formations in March. Canada geese are easily identified by their size — few common birds are larger — and their 5-foot-plus wingspans. They are the only geese that have black necks, black heads and white chin straps. Males and females look alike, but there are several races of varying size. The geese in and around the Twin Cities are a population of the giant race. Male giants weigh about 14 to 16 pounds and females 10 to 12 pounds. Canada geese mate for life, and pairs remain close to each other as much as possible. They start breeding in their third year.

Nesting sites are usually chosen in March. Eggs are laid in late March or some time in April. The female chooses the nest’s location, generally close to where she was hatched herself. The nest is usually by water, preferably on a small island, a muskrat house or a beaver lodge. She alone will incubate the eggs. The usual clutch is five or six eggs, and they normally hatch 28 days after the last egg was laid. During the nesting period, the female will lose 25 percent to 30 percent of her body weight due to the fasting that incubation imposes. The male stands guard during nesting, making sure that late-arriving geese do not enter the territory and that foxes, raccoons and other potential predators are driven off. Soon after hatching, both parents lead their brood of 4-ounce, downy goslings across a waterway to a safe hillside, where they graze on tender new blades of grass.

Jim Gilbert’s Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. His 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.