I have been talking with beekeepers. Several have told me that they were from the April 10th load. Many are almost done with their second box. The April 22nd load are putting on their second box.
Some first loaders are supering two deep colonies and starting to get a little nectar.
There is a good nectar flow going on in some areas Black Locust are starting to bloom.
My friend who brings 200 colonies back from Texas put supers on his colonies on Wed and went through them today checking on his queens for the first time since coming back from Texas two weeks ago. In four days the bees had put up 20 - 30 lbs of Black Locust honey.
Look for this tree it is a shrub or tree with big plumes of hanging white flowers. If you see some stop by and look to see if bees are working the flowers. http://en.wikipedia.org/wiki/Robinia_pseudoacacia
I have heard of high expectations of the Yellow Sweet Clover bloom in South Dakota due to ample moisture last fall and this spring. Yellow Sweet clover produces more honey in the Dakotas due to their general drier conditions. This seems to get the nectar flowing more there than in MN.
If you never have tried true Yellow Sweet clover honey from the Dakota's, I recommend putting that on your bucket list.