Hayasaki Uchiko Biotope is the largest biotope experimental site in Japan, utilizing approximately one-fifth of the reclaimed farmland (Hayasaki Uchiko Reclaimed Land) completed in 1970 to conduct research on plants and animals. This area was originally rice paddies created by reclaiming the inner lake in 1964 to increase food production, but now there is a movement underway to return the area to the original inner lake in order to restore the rich nature of the area. Shiga Prefecture has been partially flooding the area on a trial basis since 2001 to explore the possibility of restoring the inner lake. As a result of the monitoring survey, it was confirmed that a variety of organisms, including native fish species, inhabit the area, so the land in the test waterlogged area was acquired and concrete efforts to restore the lake were begun. Since the biotope experimental survey began, the number of whooper swans has increased year by year, and the area is now one of the most popular flyover sites in Shiga Prefecture.