Why did one of the two youngest birds suddenly die in the balcony bird s nest

I think if the youngest one will die, it may be because of lack of nutrition, because nature has it, that is, the habit of keeping the big and abandoning the small, he thinks that in nature there is only the strong one, and the habit of being able to live can be discounted, but you are talking about a big bird, if you push a small bird down, maybe the big bird is a magpie, because in nature, magpies have a habit, that is, they only give birth to but do not raise, they will lay their eggs in the nests of other birds, If they let it hatch the hatched magpie cubs, it is for better resources, and if they are afraid that the adoptive parents will identify him, he will push the rest of the birds down and fall to death.

This is the case in the animal kingdom, the survival of the fittest, the strong are kings, and the mother bird will choose the healthiest children to raise and grow up, and will not hesitate to abandon the weak.