Early quantity discrimination in the wild: first insights from juvenile great tits

Quantity discrimination is an important aspect of numerical cognition that is utilized across taxa in various ecological contexts, including foraging and predator avoidance. Recent research has identified that the developing young of several species possess spontaneous quantity discrimination abilities, though these are often limited compared with adults. These studies have been conducted exclusively in captivity using visual stimuli, and so there is a need for studies investigating quantity discrimination abilities in developing young in the wild. In this study, we presented post-fledgling juvenile great tits (Parus major) with the mobbing calls of one, three or five conspecific callers, and one, three or five heterospecific (blue tit, Cyanistes caeruleus) callers to investigate their quantity discrimination abilities in an anti-predator context. Juvenile great tits were more likely to respond to playbacks of multiple callers compared with one caller, regardless of whether callers were conspecific or heterospecific. These findings support those of previous work in captivity and suggest that quantity discrimination abilities are present from an early age. As the first study to our knowledge to investigate quantity discrimination in developing young in the wild, our results have important implications for the ontogeny of quantity discrimination, as well as its adaptive value to wild animals.