In: Biology
A common bird is more likely to be fossilized.
Rare slug or common slug, they are rare to be fossilized. This is because, slugs are soft bodied animals, and so they get decayed and decomposed when they die, so there isn't any chance for them to become fossils.
The rare bird is less likely to get fossilized because, fossilization is a very rare process, of all the organisms that have ever lived, only a tiny percentage of them ever become fossils. The reason for this is that, when an animal dies, its body is quickly eaten by scavengers, and the remaining flesh is eaten by insects and bacteria, leaving behind only bones. Again with passing years, the bones get scattered and fragmented into small pieces, gradually turning into dust and returning their nutrients to the soil.
So when the bird is rare, which means few in number, then they have less chance to get fossilized.
Whereas common bird, with it's more number, has more probability to get chance to be fossilized.