I've noticed something that seems odd to me, my bees are "rummaging around" some potted blueberry plants. That is to say they are landing in the pots and crawling around on the soil, presumably collecting something. The plants themselves are just starting to leaf out, but the bees seem to be interested in the soil surface. I am curious what they might be interested in in potting soil. Any ideas? (FWIW, the "soil" is peat moss, coir and perlite and was just mixed up a few weeks ago).