The migratory birds known as corncrakes were once populous throughout the U.K., until mechanized mowing destroyed their grass and meadow habitats. In 1993, there were only 480 calling males left in the entire nation. Then, conservationists lobbied for delaying mowing dates to later in the year, which gave flightless corncrake chicks more time to escape their nests and increased time for breeding.

The results were quick and substantial: By 1998, the number of calling males was up to 589. In 2003, it reached 832. Led by the Royal Society for the Protection of Birds, the census numbers continue to climb.