The BP oil disaster has affected dozens of bird species, from big, colorful wading birds to tiny, seldom-seen songbirds. The disaster affects birds at two levels. At the individual level, every bird matters, and the suffering of individuals is unjustified. At the population level, the disaster is most threatening to species that already face several other threats - especially habitat loss - and are undergoing population declines. Audubon scientists are most concerned about bird species that depend on sandy beaches and barrier islands and salt marshes. Here's an introduction to a few of these very special birds.