watering bees

I filled a boardman feeders with 1) filtered water, 2)water with a trace of honey b healthy, 3)water with a trace of kosher salt or 4)water with lots of kosher salt. The results are no success with bee watering. Additionally, I have 3 birdbaths that are not attracting bees. This year I am using woven plastic straw rafts in the (unlikely) event that a bee lands in the birdbath. Last year I attached, the plastic straws with hot glue, but those rafts were easily damage by freezing winter temperatures. With regular day time highs in the 80's Fahrenheit, where are the bees gathering water? Clearly, somewhere else. For a few hot days, a small number of bees were collecting water at the "bird girl" statue--see photo.