Wasps are mainly predatory carnivores. They hunt small insects for their own food, and to feed their young. You will see wasps visit flowers, however, for two reasons. They drink flower nectar for quick energy while they hunt, and they use flowers as a hunting ground for smaller insects that are also attracted there. In fact, several kinds of wasps are beneficial in gardens, since they are predators of insects that damage plants.
The most common wasps that you will see in Canada are yellow jackets, bald faced hornets and paper wasps. These are all social insects that live in colonies. The colonies mostly die over winter; only mated females survive, starting a new brood of female worker wasps each spring. Because the colonies increase in size during the summer, you will probably notice more of the social wasps in late summer and fall. If you see many wasps of the same kind in your observations, especially late in the season, they are probably one of the social wasps. If you see only one or two of a particular kind in late summer, it is likely a solitary wasp.
There are many species of solitary wasps, such as the Vespid wasps. They shelter in small holes in logs or in the ground, and live an independent lifestyle. Like all wasps, they are mainly predators of small insects, but some species collect pollen to feed their young.
Wasps can be identified by their slender, needle-thin waists, oval eyes and long antennae. They also generally have smooth bodies, unlike the hairy bodies of bees and flies. Most wasps sting, but only the females, since the stinger is a modified ovipositor (egg laying structure) in infertile worker females.