Impact of COVID-19: Decrease in the Number of Fledging Barn Swallow Chicks in Tokyo

Barn swallows that have crossed the sea from Southeast Asia usually appear in the Kyushu Region of Japan around March after passing through Okinawa Prefecture. When the climate becomes warmer, these birds then move further north, nesting and raising their chicks in various parts of Japan. It is worth noting that barn swallows typically nest on man-made objects, for example, the roofs of houses and barns. It is believed that this is because barn swallows protect their eggs and chicks from foreign enemies such as sparrows and crows so they build their nests in populated areas. The barn swallow’s behavior of using the presence of people to keep foreign enemies away shows that barn swallows are quite wise. However, it has been reported that from the spring to summer of 2020, barn swallows, nesting and raising their chicks, which were seen every year, were not found in various parts of Japan. Therefore, we investigated the relationship between people’s self-restraint from going out and the fledging of barn swallow chicks in Tokyo metropolitan during the corona virus disease 2019 (COVID-19) era. The results of the survey showed a link between people’s refraining from going out and the fledging of barn swallow chicks. Next spring of 2021, the termination of COVID-19 is an important environment for swallow chick fledging.