There are usually two eggs per nest but usually only one chick survives.

In the broken nest there are no whole eggs

Mr. McMurphy... my friend... I'm not a chicken, I'm a rabbit. The doctor is a rabbit. Cheswick there is a rabbit. Billy Bibbit is a rabbit. All of us in here are rabbits of varying ages and degrees, hippity-hopping through our Walt Disney world. Oh, don't misunderstand me, we're not in here because we are rabbitsーwe'd be rabbits wherever we wereーwe're all in here because we can't adjust to our rabbithood. We need a good strong wolf like the nurse to teach us our place.

We're surprised she would have spent that long away from her nest when she had a chick. That begs the question: Why does she need to go that far? It raises the suspicion that fish resources around Christmas Island are not currently adequate. That might explain the slow and gradual decline of the bird.

all of our eggs in one basket.

Why are you being so nice to me?' I asked her.
'You know,' she said, 'when you say stuff like that I just want to slap you.'
'What?'
'You heard me.' She picked up her beer and took a swallow, still watching me. Then she said, 'Colie, you should never be surprised when people treat you with respect. You should expect it.'
I shook my head. 'You don’t know-' I began. But, as usual, she didn’t let me finish.
'Yes,' she said simply. 'I do know. I’ve watched you, Colie. You walk around like a dog waiting to be kicked, and when someone does, you pout and cry like you didn’t deserve it.'
'No one deserves to be kicked,' I said.
'I disagree,' she said flatly. 'You do if you don’t think you’re worth any better.