Nishi-ike Pond in Ikeoku-cho, Nagahama City is located at the southern foot of Kotani Mountain, where Nagamasa Asai's castle was located. This small reservoir is equipped with a telescope in the observation hut, making it easy to enjoy waterfowl watching. Birds such as the great tanager, geese, mandarin ducks, and mallards fly to the pond, and the West Pond is particularly famous for being the southern limit for the arrival of the great tanager in Japan.