I can tell it's spring because the Unequal Cellophane Bees (Colletes inaequalis) are out and about in my neighbor's yard! Please enjoy this bee investigating a crocus. (Sadly these flowers are introduced and may not help this native bee, but this bee is determined to find out.)
If you're wondering why they're "Unequal", inaequalis in Latin apparently also means "impermanent"; they only emerge briefly.