Leaving the Nest, or Not

I came across two abandoned bird nests this week at Struan Farm. The first was in one of our two stands of QE II Trust protected native bush:

Wedged in the center of a ponga/tree fern, what a creative, cozy nesting spot!

The occupants were long gone. The second nest I found near an area of bush we are cleaning up, and is a somewhat sadder tale:

Hard to know what happened here, but the nest was well protected, looks to me like mum didn't return.