A butterfly feeding on nectar of common milkweed flowers, "Asclepias syriaca".
When little else is flowering in early-mid spring in Southern Ontario, native hoptree blooms with inconspicuous tiny green flowers. You'll find it swarming with pollinators however! The tongue of this bumble bee is extended and collecting nectar. Butterflies love it too. The leaves of hoptree are one of only two food sources for the caterpillars of the giant swallowtail butterfly.
Bumble bees foraging on blue flag iris are a common sight in our biodiversity garden (plant: blue flag: "Iris versicolor", Iridaceae).