Investigating the relationship between heat-mediated cognitive impairment and antipredator response in a wild bird

Abstract

Increasingly frequent heatwaves require animals to spend more time thermoregulating at the expense of other fitness-related behaviours. Emerging evidence also indicates that high temperatures can impair cognitive function in wild animals. However, whether such heat-mediated cognitive impairment underpins altered behavioural responses during high temperatures remains unclear. We examined the link between naturally occurring high temperatures, cognitive performance and antipredator response in wild southern pied babblers (Turdoides bicolor). In a paired experimental design, we performed model predator presentations using a taxidermied common genet (Genetta genetta) and a box as the control, and we quantified associative learning performance—a cognitive trait involved in associating predator cues with a threat—for the same individuals under normal and high-temperature conditions. As predicted, individuals showed a stronger antipredator response (combining time spent vigilant, flying and alarming) when presented with the predator compared to the control under normal but not high temperatures. Associative learning performance also declined with increasing air temperatures. However, associative learning performance (whether measured under normal or high temperatures) did not predict the strength of the antipredator response. Our findings provide novel evidence for a reduced antipredator response under high temperatures and suggest that physiological constraints rather than learning impairment might explain this change.