Data from 'Warm and cool temperatures decrease early-life telomere length in wild pied flycatchers'

Dataset used in Furic et al. 2025 (submitted to J Avian Biol): 'Warm and cool temperatures decrease early-life telomere length in wild pied flycatchers'AbstractClimate change represents one major challenge for avian species. It is characterized byan increase in average ambient temperatures, but also in occurrence of extremeweather events, such as heat weaves and cold snaps. These abrupt temperaturechanges can modify the immediate and long-term survival prospects of nestlingbirds, when their thermoregulatory capacities are still not fully developed.While immediate nestling survival can easily be measured, long-term survival ismore challenging to evaluate. Early-life telomere length has been suggested asa potential biomarker of future fitness prospects. To evaluate the potentialimpact of changes in early-life temperature, we thus experimentally increased (ca.+2.8°C) and decreased (ca. -1.7°C) average nestbox temperatures in wild piedflycatchers (Ficedula hypoleuca) during nestling postnatal growth, and measurednestling telomere length before fledging. Shorter telomeres were observed inindividuals exposed both to an experimental heating or cooling during growth.Our results suggest that long-term survival prospects or long-term performanceof individuals exposed to abrupt changes in early-life temperature may bedecreased.The excel file contains two data sheets:2018 Heating experiment2019 Cooling experiment