Sugar addicted in the city: impact of urbanisation on food choice and diet composition of the Eurasian red squirrel (<i>Sciurus vulgaris</i>)

Abstract Urban wildlife faces a great variety of human-induced habitat alterations, among others changes in resource availability and composition, often resulting serious declines biodiversity. Nevertheless, Eurasian red squirrels (Sciurus vulgaris) occur high densities urban areas seem to benefit from supplementary feeding. However, we still lack knowledge about consequences urbanisation on mammalian foraging behaviour nutrient intake. Thus, investigated body mass, food choice diet composition an core area versus forest population cafeteria experiment. individuals were lower initial mass condition, but consumed significantly more g kJ per day gained weight over the course experiment (around 2 weeks); nevertheless, difference condition persisted. All preferred hazelnuts, had wider dietary range non-natural items. Both groups prioritised fat there was no protein though higher sugar intake, mainly by eating biscuits. Our results demonstrate clear effects preferences, which has potential for nutritional mismatch or negative side due consumption findings show that highly supplemented fragments might not serve as adequate refuge wildlife.