I think these reflected a kind of magical thinking when infant mortality was significantly more common -- what happened before the child died must have been the cause.
It's probably more of a list of things people are scared of and things people wish for. Relating to your comment, I'm not sure your thinking conveys what you mean - most causes of death relate to what happened before you died.
gfaure probably meant something we now would consider completely unrelated. An owl hooted twice, and then the child died. So two hoots from a certain type of owl predicts a death in the house. As silly as this sounds to us today, there's a huge survival value in making these kinds of connections. Certain smells and tastes predict toxic subtances, certain noises predict predators or natural disasters, and certain animal behaviours predict all kinds of calamities.