Chornobyl birds: How radiation transformed their lives and bodies

Great tits are one of the many species of songbirds inhabiting the Chornobyl zone. In the zone around the Chornobyl Nuclear Power Plant, abandoned by humans after the disaster 38 years ago, nature is thriving wonderfully. The area of about 1,004 square miles has become an enclave inaccessible to humans, where many species of flora and fauna develop without human interference.

The Chornobyl zone intrigues scientists. Although the war in Ukraine has hindered research in the last two years, teams are still undertaking new research projects.

Recently, experts from the Finnish University of Jyväskylä studied songbirds' reproductive behaviors and early life stages growing up in radiologically contaminated habitats. The team looked into how the radiation-exposed environment affects two common species of European songbirds: the great tit (Parus major) and the collared flycatcher (Ficedula hypoleuca).

Several nesting boxes were placed in two regions, one with high radiological contamination and the other with relatively low contamination. A series of tests was used to compare the bird families.

Scientists examined the diet and gut microbiomes of bird populations. Such comparative tests were conducted for the first time since the biggest disaster in the history of nuclear energy and one of the largest industrial disasters of the 20th century.

The disaster occurred during the night of April 25 to 26, 1986. In the nuclear reactor of power block No. 4 of the Chernobyl Nuclear Power Plant, the reactor core overheated and a hydrogen explosion occurred. Radioactive substances spread, and people had to leave the area forever as it was no longer habitable.

However, animals remained in the highly contaminated area. Despite the conditions, nature is doing well. Many species live here, including moose, bears, deer, lynxes, and wolves.

Sameli Piirto, a doctoral candidate at the University of Jyväskylä, claims that radiological contamination has consequences for organisms at an early stage of life. However, the changes that occur due to their impact on subsequent generations of animal populations are not yet fully understood.

Scientists determined that although birds occupied fewer nests in heavily contaminated areas, there were no significant differences in reproductive ecology or the health of chicks from "clean" and contaminated areas. But radiation has changed the lives of the birds.

Bird species living near Chornobyl have smaller heads and brains. It is unknown whether this affects their cognitive abilities.

Finnish research on birds did not show the long-term harm suffered by the human population, which was quickly evacuated from the contaminated lands. From the Chornobyl zone, designated not only in today's Ukraine but also partially in Belarus and Russia, 35,000 people had to move out.

Radiation after the disaster increased the risk of cancer. The accident and the displacement of many residents resulted in trauma, depression, alcoholism, and other mental illnesses.