Increasing extreme summer maximum temperatures and more variable winter temperatures can have negative consequences for birds, including mass mortality events (McKechnie and Wolf, 2010 McKechnie et al., 2021b), phenotype-environment mismatches (Boyles et al., 2011 Jimenez et al., 2020 Vézina et al., 2020 Ruuskanen et al., 2021), reduced reproductive capacities (Carroll et al., 2018 Nord and Nilsson, 2019 van de Ven et al., 2020), and altered offspring physiology and behavior (Mariette and Buchanan, 2016 Mariette, 2020). In addition to changes in average temperatures, however, global change is predicted to increase climate variability, with more frequent extreme events for many locations (Jentsch et al., 2007 Wallace et al., 2014 Cohen et al., 2018). In a continent‐wide study on birds, we show that song frequency mirrors predictable patterns of body size variation along a latitudinal and elevational gradient, suggesting climate change may drive predictable shifts in the frequency of acoustic signals that play a critical role in animal ecology and evolution. This is despite a well‐established relationship between body size and acoustic signal frequencies across the animal kingdom. Temperature‐related physiological constraints shape functional traits in animals at a global scale, yet the implications of continent‐wide morphological variation on acoustic communication signals is little understood. Our findings suggest that macroecological patterns of body size can influence phenotypic traits important in ecology and evolution, and provide a baseline for further studies on the effects of environmental change on bird song. Specifically, effects on song frequency in accordance with Bergmann's rule dwarf those of acoustic adaptation at a continental scale. Through a multilevel‐modelling approach, we demonstrate that continent‐wide morphology of related African barbets follows predictions of Bergmann's rule, and that body size mirrors variation in song pitch, an acoustic trait important in species recognition and sexual selection. Body size may also constrain other phenotypic traits important in ecology, evolution and behaviour, and such effects have seldom been investigated at a continental scale. This relationship has been summarised by two classical principles of biogeography: Bergmann's and Allen's rules. Physiological constraints related to atmospheric temperature pose a limit to body and appendage size in endothermic animals. Additionally, high ambient temperatures were not likely to be a direct factor in northern flying squirrel range shifts, but that climate warming caused G. Consistent daily rhythms in body temperature were observed in free-ranging flying squirrels, as predicted, and increased as ambient temperatures decreased. sabrinus did not show visible or physiological signs of heat stress during respirometry experiments, and an upper critical temperature was not reached at temperatures tested.

I used climate data from Arrowsic, Bangor, and Presque Isle, Maine over recent decades to determine if temperature increases would correspond to the northward movement of flying squirrels in Maine. I measured metabolic rate and evaporative water loss under different ambient temperatures using flow-through respirometry and estimated the responses to high ambient temperatures in the field by measuring body temperature. sabrinus as a study species to determine the effect of high temperatures on thermoregulation and energy use to test if thermal limits will contribute to range shifts. Because they are nocturnal and tree nesting, flying squirrels may be particularly susceptible to warmer temperatures, as they will experience the highest daily ambient temperatures during their resting phase. Two species of flying squirrel in North America, the southern flying squirrel (Glaucomys volans) and the northern flying squirrel (Glaucomys sabrinus) have undergone northward range shifts, with climate warming being the suspected driver. Climate change may potentially alter a species’ range distribution and thus the relationship between environmental temperatures and animal performance as a response to climate warming has become an important area of research.

Wave killed wildlife masse