When these pictures were taken, the coot pair which got a head start with raising young this year were still brooding the eggs. Although they shared the duty of staying on the eggs, protecting them ank keeping them warm, there were also other duties.
Here, one of the birds is carrying some vegetation back to give to the one staying on the nest. I thought at the time it was bringing some food; there’s some fuss as the material was exchanged, a bit of pair bond reinforcement. In fact, that particular piece of vegetation was still visible on the nest some days later, even once the chicks had hatched.