Bharatpur Bird Sanctuary, India

Bharatpur Bird Sanctuary, officially Keoladeo Ghana National Park, packs 354 bird species into only 29 square kilometers—a density of 12.2 species per km², which is 70% higher than the average Indian wetland reserve. This winter gem hosts up to 10,000 Siberian cranes annually, a number 25% larger than the count recorded at #3's nearest competitor, Sultanpur National Park. The sanctuary's key advantage is its compactness: a 2-hour bicycle tour (rentals available for $3 USD) circles the main wetland core and routinely yields sightings of waterfowl, herons, and the rare sarus crane, whose population here of 20 breeding pairs represents 15% of India's total.