India, Feb. 23 -- It's hard to imagine, but Delhi is the second-most bird-rich capital in the world, after Nairobi, Kenya. Bird-spotters have recorded sightings of 471 species - residents such as ruddy-breasted crake and Tickell's blue flycatcher, winter visitors from Siberia and Central Eurasia, passage birds such as the greater flamingo, and chance sightings of the Terek sandpiper....