On the property where I have 2 strong hives of honey bees there are 3 sour cherry trees that are now in full bloom. There are a lot of small bees on the flowers of these trees, and almost all of them are not honey bees. They are about 3/4 the size of an average honey bee, black, and have no stripes.
These bees were on the cherry blossoms last year as well as this year. What are they?
They are likely either Halictidae (Sweat bees), Andrenidae (Mining bees), or Megachilidae (Mason bees, leafcutter bees). Look up solitary bees for your state you might find pictures of what you are seeing. There is quite a large diversity amongst solitary bees but they are more elusive and you have to have a keen eye to notice them like you have.