I am not certain if this question really fits under Political Philosophy, I feel it fits better into philosophy of law as this is the kind of question they would often ask in Ancient Rome, however where I categorise this needn’t be an issue.

If my bird lays an egg in your garden, who does it belong to?

The question here is whether property of the bird is more important than property of the place the bird lays an egg.
Instead of handling this question as it is, I will ask a further question. If my bird lays an egg in my garden, why do I own it? I suppose I would argue that I own the bird, therefore the eggs are mine. I doubt many would argue that they are mine because they were laid in my own garden. Here it seems that property of the bird is more important than where the eggs are laid.

Suppose my bird lays an egg on the street (a place that no one owns) then do the eggs belong to me? I would still argue that they do. Property requires a property holder, and if those eggs belong to no one then are they up for grabs? I have more claim over those ‘unclaimed’ eggs because the bird is mine, something no one else can claim. Again, here it seem property of the bird is more important.

Alternatively, if an unclaimed bird lays an egg in my garden, I own those eggs because even of those eggs are ‘unclaimed’, they have a stronger connection to me, which no one else has.

I could go on and on with examples which show conflicting results, but let me just add one more thing. If I give birth in your house, does the baby belong to you? I would doubt that anyone would argue that it is, but I have difficulty explaining how.

So, do the eggs of my bird belong to me if they were laid in another garden?