Nest

Opened the back door and there on the deck was this. Looks to me like a wren's nest. I guess it was left as a present for us by the cat which upsets me a lot. To start with we don't have a cat. She is supposed to live a few doors up the street but spends all her days lurking around our garden.
But what bugs me most of all is the fact that we have had a wren in the garden for a while now and it looked like he had found a mate and started home building. That cat is going to get swatted by me one of these days if I ever find out that she chased my wrens off the premises.
For the record, the bowl of this nest is just 40mm (apprx 1.5 inches) in diameter.