I think it is peoples ability to really empathise that drives them to help others, even animals. I also think that the ability to empathise comes from our own life experiences, as we may have felt similar degrees of pain /emotion.

So there is the double edged sword - on the plus side, the motivation to help others who are suffering, but the flip side is that we may have developed this "skill" due to our own internal struggles - and maybe you just can't have one without the other.

My T even said to me that those who feel so deeply are moved to relieve others suffering, as by doing so it also relieves their own pain that is generated by witnessing the suffering of others - he said that is one factor that motivates people into becoming T's.

Not sure what I am trying to say, other than remembering a crow that I stopped to help once - everyone else drove past him as he lay there helpless.

I am sorry that witnessing that pigeon has triggered more intense feelings for you, life is not perfect for anyone, animals included, but don't forget that it was a good thing you did.