Many of the pits were lined with the skin (including the feathers) of a swan, on top of which were placed varying amounts of eggs almost ready to hatch, pebbles, and bird parts and claws from various types of birds. The spring was lined with quartz and contained things like nail clippings, human hair, straight pins, and small pieces of cloth. Part of a cauldron was even found.
Quoting from the article, the archaeologist, Jacqui Wood, said:
"Over the last 30 years I've been quick to dismiss ritual as an explanation for unusual archaeological finds. It usually means that the archaeologists can't think of anything better. So now it seems especially ironic that I end up with a site absolutely full of ritual."
The earliest dates for the pits are the mid-1600s. Whatever was being done here was important enough for the practitioners to risk being pointed out as witches. The 1600s were a dangerous time to be caught doing anything with a pagan tinge. It was doubly risky because swans were symbols of royalty and owned by the crown. And apparently whatever these practices meant is still important. One of the pits dates from the 1950s. It was lined with the skin of a dog and contained dog teeth and the baked jaw of a pig.
Old magic and magical thinking is still among us.