Where the water meets the sky

We visited a new-to-us park today; a neighbour across the road had mentioned it to us a couple of times, and with today being another lovely sunny day we decided it was time to investigate. St. Catherine's is certainly somewhere to add to our list of nearby walks. We followed the signs for the woodland path, and before we'd gone too far we could see a shimmer below. Looking more closely we realised it had to be the Liffey.
Further along the path descended to run closer to the river, and there was a small un-gravelled trail which brought us right along the banks.

We saw plenty of birds - the chaffinch here, but also a heron, a tree-creeper, some jays, a wren and the first swifts or martens of the season. I don't think I've ever seen a tree-creeper before - it was fascinating watching it climb up and round the trees. If I hadn't seen him landing in the first place I'd almost have thought it was a mouse spiralling round the trunk.

We hear the birds singing all the time in the garden here, but with all the trees growing along the railway line it's rare to see which one is actually singing to identify it. No questions about this chaffinch, he was singing his heart out.

This ruin had a sign on the wall saying Lower Yard. But all my searching hasn't been able to come up with much information about what the various ruins in the park are.