The Lasting Effects of Perceived Predation Risk on the Avian Brain and Behaviour

Predators affect prey populations not only through direct killing, but also through perceived predation risk – the ‘fear’ of predators. Responding to predation risk is critical for prey survival, however perceived predation risk can have lasting effects ranging from individual changes in neurobiology up to population level effects. I manipulated perceived predation risk using auditory playbacks of predators or non-predators in wild caught black-capped chickadees (Poecile atricapillus) in acoustic isolation and wild caught brown-headed cowbirds (Molothrus ater) in large outdoor aviaries. I found changes in dendritic morphology and inhibited neurogenesis in response to increased perceived predation risk lasting at least one week. I also found changes in both escape behaviour and in the response to a conspecific alarm call. My research shows that perceived predation risk has long-lasting effects on both the brain and behaviour, with applications for both ecologists and biomedical researchers

P31. Assessing the long term effects of perceived predation risk on the avian brain

Predators affect prey populations not only through direct killing, but also through the perception of predation risk. Responding to predator threats is critical for prey survival, however perceived predation risk can have lasting effects ranging from individual changes in neurobiology up to the population level. My research focuses on the lasting effects of predator ‘fear’ on the avian brain. I will be using auditory playbacks to manipulate predation risk in black-capped chickadees (Poecile atricapillus) in acoustic isolation and brown-headed cowbirds (Molothrus ater) in large outdoor aviaries. Lasting behavioural changes have been found in black-capped chickadees one week after exposure to increased perceived predation risk, and I will be looking for long lasting changes in brain morphology and activation in regions thought to be involved in the avian fear network. My research aims to connect laboratory methods used to quantify the effects of fear in the brain with behavioural and physiological changes found from perceived predation risk in the field

Predator-induced fear causes PTSD-like changes in the brains and behaviour of wild animals

© 2019, The Author(s). Predator-induced fear is both, one of the most common stressors employed in animal model studies of post-traumatic stress disorder (PTSD), and a major focus of research in ecology. There has been a growing discourse between these disciplines but no direct empirical linkage. We endeavoured to provide this empirical linkage by conducting experiments drawing upon the strengths of both disciplines. Exposure to a natural cue of predator danger (predator vocalizations), had enduring effects of at least 7 days duration involving both, a heightened sensitivity to predator danger (indicative of an enduring memory of fear), and elevated neuronal activation in both the amygdala and hippocampus – in wild birds (black-capped chickadees, Poecile atricapillus), exposed to natural environmental and social experiences in the 7 days following predator exposure. Our results demonstrate enduring effects on the brain and behaviour, meeting the criteria to be considered an animal model of PTSD – in a wild animal, which are of a nature and degree which can be anticipated could affect fecundity and survival in free-living wildlife. We suggest our findings support both the proposition that PTSD is not unnatural, and that long-lasting effects of predator-induced fear, with likely effects on fecundity and survival, are the norm in nature