Dyan deNapoli (who apparently goes by the moniker "The Penguin Lady," which is awesome) was very, very put out by a suggestion during the Gulf Coast oil spill that oiled birds should be killed because they're going to die anyway.
The Penguin Lady knows that this is not necessarily true, because in 2000, she took part in a rescue of over 20,000 birds, oiled in a spill off of the coast of South Africa. Only 160 died. Above, deNapoli explains to a TED conference how they did it.
Basically, it's a lot of hard work. But so is euthanizing thousands of living creatures.