It's also worth mentioning that cleaning birds after an oil spill isn't always even helpful. Some birds, like gulls and penguins, do pretty well. Others, like loons, tend to do poorly. Here are some articles concerning cleaning oiled birds.

http://www.npr.org/templates/story/story.php?storyId=127749940

http://news.discovery.com/animals/experts-kill-dont-clean-oiled-birds.htm

And I know that the oiled birds issue was only an example, but I just wanted to point out that this issue, much like the "Food and clothing aid to Africa" examples you often see, isn't necessarily a good idea even ignoring opportunity cost.