While walking in the woods the last week I've seen several Common Garter Snakes sunning themselves in openings. I love to see them reemerge in the spring after their hibernation.
I do not yet have Garter Snakes in my yard but I am working on providing the ideal habitat for them by piling some rocks, fostering vole and rodent holes and leaving all the leaf litter and branches on the ground.
In late April you will see masses of Garter Snakes writhing in the leaf litter, also called "mating balls". The males emerge first and wait to mate with the females. Males outnumber females so there is heavy competition. (Source)
Reptiles & Amphibians of Minnesota Field Guide)
Look for "mating balls" near water in mid to late April in Minnesota.
Garter snake habitat is highly variable including prairies, woodlands, grassy meadows and wetlands.
In summer they hunt for prey during the day. I often see Garter Snakes taking refuge in rock crevices like this man-made stone pillar.
Garter Snakes hibernate in winter in "underground mammal dens, crevices and foundations". (Reptiles & Amphibians of Minnesota Field Guide)
Do you have Garter Snakes in your yard?