Compensatory growth affects exploratory behaviour in zebra finches, Taeniopygia guttata

Individuals with reduced body mass resulting from early nutritional stress often compensate for this later in growth. This compensatory growth can be beneficial as individuals adjust their body mass to the level of individuals that grew up under better conditions. Yet, compensatory growth can also result in costs that are paid later in life. In zebra finches raised under different nutritional conditions, we tested whether compensatory growth affects subsequent adult exploratory behaviour, a proxy for an avian personality trait. We tested their exploratory behaviour in a spatial test to find hidden food on 2 consecutive days. The behavioural measures of exploration correlated with each other across time showing a high individual behavioural consistency. Early nutritional treatment itself did not affect exploration and feeding. Yet, birds with higher previous compensatory growth were less active and approached the food with different latencies from birds with lower compensatory growth. Life history decisions on whether to compensate for a bad start or stay small thus result in elementary differences in behaviour, such as exploratory behaviour, with potential fitness consequences, depending on payoffs of explorative strategies in different environmental conditions.