Trumpeter swans have made a remarkable recovery from near-extinction to over 30,000 birds today, leading to their removal from the endangered species list. Conservation programs protected habitat, banned hunting, and even reintroduced birds to former ranges. The species is now considered 'no longer endangered' (Option D) - a true conservation success story. While not as abundant as some waterfowl, trumpeter swans have stable, growing populations across their historic range. This recovery represents one of North America's most significant species restoration achievements.