OK, so the ‘Mom’ thing is an assumption. However, the youngster was almost glued to the adult.

They walked back and forth in front of me and perhaps only once did the juvenile move off exploring.

He did watch me though.

I took this photograph of the young bird when he was distracted by something in the water.

Nice photos! It seems they’re quite curious, and not anxious of humans.
They were OK as long as I was in full view on the banks of this marsh. Thanks.