Artificial light at night and telomere shortening

This data file contains information about telomere dynamics, body condition, and nitric oxide levels in great tit (Parus major) nestlings exposed to, and not exposed to, artificial light at night (ALAN). Relative telomere length (RTL) and body condition (residuals of a regression predicting body mass from tarsus length) were assessed for each nestling both before the beginning of experimental exposure to ALAN (on day 8) and following exposure to ALAN (on day 15). Nitric oxide levels (nmol/ml) were assessed from plasma samples on day 15. Information about nestling sex, brood size, and size rank within the brood (largest nestling = rank 1) is also provided.