TY - JOUR AU - Gardner, Janet L. AU - Rowley, Eleanor AU - de Rebeira, Perry AU - de Rebeira, Alma AU - Brouwer, Lyanne PY - 2018 DA - 2018/03/27 TI - Associations between changing climate and body condition over decades in two southern hemisphere passerine birds JO - Climate Change Responses SP - 2 VL - 5 IS - 1 AB - Climate change presents considerable challenges for endotherms because they must maintain high, relatively constant body temperatures across a range of environmental conditions to ensure survival and optimise performance. Individuals exposed to changing weather must manage energy and water allocation to maintain thermal homeostasis, with consequences for body condition, and hence there is potential for selection because body condition is strongly linked to fitness. Understanding how weather drives changes in body condition is therefore fundamental to understanding how fitness is affected by climate change. Here we test for associations between weather and body condition and how this changes over time, in two co-existing species of small insectivorous passerines, the red-winged fairy-wren, Malurus elegans and white-browed scrubwren, Sericornis frontalis, that have been the subject of a ringing study for 39 years in temperate south-western Australia. The study populations have experienced increases in minimum temperatures in winter and summer as well as decreases in the frequencies of days with thermal minima < 5 °C, but the summer climate remains relatively mild with few days experiencing thermal maxima > 35 °C. Although, warming temperatures may reduce thermoregulatory costs, repeated exposure to hot conditions has been shown to have negative effects on body condition. Thus, we predict that the reduction over time in daily minima < 5 °C, along with the influence of increased maximum and minimum temperatures in summer and winter, will have positive effects on body condition. SN - 2053-7565 UR - https://doi.org/10.1186/s40665-018-0038-y DO - 10.1186/s40665-018-0038-y ID - Gardner2018 ER -