I discovered fully opened tulip poplar flowers in the backyard. Previously I only found tulip poplar flower heads which were not fully opened. The squirrels are very helpful in nibbling flower heads and then dropping them to the ground for my inspection. This may be the big nectar flow that the bees have been waiting for.
Earlier, I may have made a blog error reporting that all my spring markers appeared before day 71. Actually I now think that the invasive Asian Wisteria bloomed after day 71.