Australian songbird body size tracks climate variation: 82 species over 50 years.

The observed variation in the body size responses of endotherms to climate change may be explained by two hypotheses: the size increases with climate variability () and the size shrinks as mean temperatures rise (). Across 82 Australian passerine species over 50 years, shrinking was associated with annual mean temperature rise exceeding 0.012°C driven by rising winter temperatures for arid and temperate zone species.

Are long-term widespread avian body size changes related to food availability? A test using contemporaneous changes in carotenoid-based color.

Recent changes in global climate have been linked with changes in animal body size. While declines in body size are commonly explained as an adaptive thermoregulatory response to climate warming, many species do not decline in size, and alternative explanations for size change exist. One possibility is that temporal changes in animal body size are driven by changes in environmental productivity and food availability.