At the beginning of March, 2015, a small flock of goosanders [common mergansers], カワイサ (kawaisa in Japanese) appeared at Yasugawa near my home, about 12km upstream from Biwako. I’ve often seen these birds at Lake Biwa, but I’d never seen them this far upstream in Yasugawa. They stayed at a distance, but on March 8 they came close enough that I was able to make a short video recording of them feeding beside a great egret.
Every time I saw the goosanders here, they were in swift water near a flock of cormorants or a lone great egret. In the distance I could see them swimming very near the larger birds. They seemed to dive shallower than cormorants. When I saw saw them with the other birds, I wondered if these different species of fish-eating birds were cooperating by fishing near each other.
Music credit: “Kamakura” by Ben Timm, “The Official Karian” on SoundCloud (http://soundcloud.com/karian121/kamakura).