Long-lasting negative effects of poor early life conditions on cognitive performance in adulthood in a wild bird

Adverse conditions encountered during growth, such as stress or malnutrition, are known to affect cognitive development and functions in adulthood in humans and laboratory animals. However, how early life conditions can influence adult cognition in wild animals remains unclear. Yet cognitive abilities such as innovation can be crucial for animals to cope with rapidly changing environments. We examined whether growing conditions (measured by hatching date, brood size, fledging body condition, parents’ age and condition) predict problem-solving, neophobia, accuracy, activity and exploration in adulthood in a natural population of great tits (Parus major). Over 10 years, 348 nestlings recruited locally were tested as adults on a problem-solving task. The results show that nestlings in poorer condition were less likely to become solvers and more prone to making errors when solving problems. Our results provide rare evidence from a natural population that adverse conditions experienced during development can have negative, long-lasting effects on cognitive traits in adulthood, particularly the ability to solve problem, which has previously been shown to rely on associative learning and affect breeding performance in this population.