The choice and handling of supplemental food by red squirrels in an urban park.

One of the main factors that allow the red squirrel (Sciurus vulgaris) to live in cities may be the availability of supplemental food provided by people. In this article, preferences of red squirrels in relation to supplemental food, how it is handled, and whether change seasonally, is investigated. A cafeteria test was performed, in which squirrels could choose one from six kind of nuts. Three types of nuts were used: walnuts, hazelnuts and peanuts, with unshelled and shelled nuts of each offered. In most cases squirrels took an offered nut. If a nut was not taken, it was mostly due to lack of interest, without signs of fear. Regardless of season, whole, unshelled walnuts were selected most frequently - the most high-energy and least perishable from offered food. The least frequently selected overall were peanuts. Caching behaviour changed seasonally - nuts were mostly eaten in spring and hoarded in autumn and it took less time to cache nuts in autumn and winter. It may reflect optimal caching strategy at the time when food is abundant and there is a desire to secure as big a store of food as possible. Results from the study suggest that supplemental food is an important component of squirrels' diet and have an impact on their caching strategies.