From hummingbirds to wood frogs, prairie wildlife prepares for winter. Today marks the official start of the fall season, and the tall grass prairie is showing its first signs of fall as birds, plants, and animals shift into seasonal survival mode. Nature interpreter Norm Gregoire says the landscape may still seem alive with summer colour, but subtle changes are underway. “Some of the more summertime blooms are starting to wither a little bit. Some of the leaves are starting to fall,” he says. “But what some folks don’t realize is that early September actually brings new blooms too, so there’s still fresh growth even as other plants fade.” Alongside these plant changes, birds are on the move. Gregoire says summer migrants are leaving while familiar winter species like chickadees and blue jays are becoming more noticeable again. He’s also observed an increase in hummingbird activity as they fuel up before their long journey south, even sharing feeders instead of competing. Native prairie grasses are now at their peak height, with towering big bluestem standing more than two metres tall. Gregoire says the plants are losing chlorophyll and shifting into dormancy, while late-season species are just coming alive. “Even threatened plants like Riddell’s goldenrod and the very tiny but fragrant Great Plains lady’s tresses are starting to bloom right now,” he says. Animals are also busy storing energy for the colder months ahead. Squirrels are gathering seeds and cones, while berry-eating animals are bulking up. Gregoire notes that even frogs are getting ready in fascinating ways. “Wood frogs have a chemical compound in their blood that works like an antifreeze,” he explains. “They can freeze solid under a layer of leaves all winter, then thaw and come back to life in spring.” Gregoire says the whole prairie gradually “shifts gears” with wind changes that bring huge flocks of geese, cranes and common nighthawks heading south. A cold snap can quickly speed the transition, while warmer weather can briefly delay migrating species. “This transition period is some of my favourite times of year,” he says. “That summer into fall—it’s such a beautiful time of year to be outside.” -With files from Carly Koop.