A friend has some stag hides in lime-water solution. He noticed the stag hides were covered in bees of several different species. He also noticed that the nearby sheep hides in a similar bath have no bees. What attracts the bees to the stag hides? Alternatively, what repels them from the sheep?
There are a lot more bees when the sun shines. The bees principle seemed interested in the hairy side of the hides. There is a small stream and a dried up pond nearby, so probably other places if they just wanted a drink. There is no noticeable scum on the water of either container.
Photos of the stag hides:
Photo of the sheep hides: