Variable and mismatching temperature regimes impair song learning in zebra finches

Climate change is characterized by extreme climatic events and unpredictable environmental conditions, increasing the probability of condition mismatch during the lives of animals. Mismatched conditions between development and adulthood can negatively affect traits, especially those subjected to developmental programming. Thus, an environmental mismatch between song acquisition during development and song production during adulthood could affect the song quality and reproductive success of birds. In this study, the effects of temperature variability and condition mismatch on song learning and production in captive zebra finches, Taeniopygia castanotis , were investigated. Males developed in either stable or variable temperatures, and then experienced a mismatch in thermal conditions at independence. Their crystallized song was recorded at adulthood, and their song learning and quality traits were evaluated. Condition mismatch affected only song traits acquired during development, with a decrease in the proportion of syllables copied from the tutor and a trend towards decreasing repertoire size. The syllable learning accuracy also tended to be lower for birds experiencing variable temperatures. Other song learning and quality traits were unaffected by temperature variability or condition mismatch. Collectively, our results indicate that climate change can negatively affect song learning and quality in songbirds. • Condition mismatch at independence decreased the proportion of copied syllables. • Birds developing in variable temperature learned their syllables less accurately. • Variable conditions had no effect on song production and spectral characteristics.