Interesting article, sounds a very good introduction to scope insensitivity.

Two points where I disagree :

1. I don't think birds are a good example of it, at least not for me. I don't care much for individual birds. I definitely wouldn't spend $3 nor any significant time to save a single bird. I'm not a vegetarian, it would be quite hypocritical for me to invest resources in saving one bird for "care" reasons and then going to eat a chicken at dinner. On the other hand, I do care about ecological disasters, massive bird death, damage to natural reserves, threats to a whole specie, ... So a massive death of birds is something I'm ready to invest resources to prevent, but not a single death of bird.

2. I know it's quite taboo here, and most will disagree with me, but to me, the answer to how big the problems are is not charity, even "efficient" charity (which seems a very good idea on paper but I'm quite skeptical about the reliability of it), but more into structural changes - politics. I can't fail to notice that two of the "especially virtuous people" you named, Gandhi and Mandela, both were active mostly in politics, not in charity. To quote another one often labeled "especially virtuous people", Martin Luther King, "True compassion is more than flinging a coin to a beggar. It comes to see that an edifice which produces beggars needs restructuring."