Neophobia, or the fear of novelty, is thought to restrict animals’ ecological niches and hinder their propensity for innovation; two processes that should limit behavioural adjustment to human-induced changes in the environment. However, birds within the corvid family Corvidae defy this trend by being highly neophobic, yet highly successful alongside humans across diverse habitats. This thesis examines the causes and ecological consequences of neophobia to unravel corvids’ puzzling neophobic tendencies. Throughout the thesis I find evidence that corvids are very neophobic, but that individuals differ in their level of novelty avoidance. Neophobia is not a fixed trait across time and towards all types of novelty. Neophobia levels differ depending on the type of novel stimuli being presented, and individuals can be inconsistent when environments change seasonally (Chapter Three). Although individual differences in neophobia are expected to be associated with fitness outcomes, I found no direct connections between neophobia, reproductive success or offspring stress hormone expression (Chapter Four). Moreover, if neophobia levels were defined by human presence, populations should differ in their novelty avoidance according to their proximity to humans. However, corvids show similar patterns of object neophobia between urban and rural areas (Chapter Five). The lack of connection between neophobia, fitness, and urbanization indicates that corvids might be able to circumvent individual differences in neophobia that might otherwise restrict behavioural adjustment. Accordingly, experience observing conspecifics consume novel foods and approach threatening objects encourages individual risk-taking, such that highly neophobic individuals could benefit from social information (Chapter Six). I therefore propose that corvids’ flexibility and their success alongside humans may be due to their ability to overcome their fear through learning. How animals make decisions in the face of ecological novelty may predict whether they behaviourally adjust to human-altered habitats and is relevant in the wider context of species conservation.