Mushishi Bangai-hen: Jikakeru Kage

Seven years since the rare solar eclipse occurred, Adashino continues to assist those in medical need. After visiting a patient at a beachside home, the tactful doctor notices a shadow resembling a bird. This spontaneous sighting leads Adashino to reminisce about a story Ginko once told him about a Mushi that assumes the same form. Such a revelation, however, may lead to false optimism.
(Source: MAL Rewrite)