Artificial light at night disrupts the molecular clockwork. When songbirds (Great tits) experienced light pollution, they moved part of their activity to the night. Some genes showed parallel change in expression, but others kept the original pattern. Thus, the birds suffered internal desynchronization. Similar desynchronization was found for metabolites of the birds; from Dominoni et al. 2021; https://www.nature.com/articles/s41598-022-05059-4. These same birds also came prematurely into breeding condition.