Well done to @jborrases and @olivetreeann - yesterday's pic was a shiny holographic gift bag! In colour you'd probably have recognised it straight away, but in B&W it does look quite mysterious.
I don't think it's bubbles- it looks more like a scrubby you wash your dishes with. But then those little white flecks look like bird seed, so maybe it's the "carpeting" in one of the girls' cages.