Spatial organization, behaviour and feeding habits of red squirrels: differences between an urban park and an urban forest

Abstract

Red squirrels (Sciurus vulgaris) successfully inhabit cities, utilize urban structures and adapt to alternative food sources such as supplemental anthropogenic feeding. Here, we compared two urban populations: one in a busy park and another in an urban forest. The first was expected to be highly influenced by human presence (and food delivered by park visitors), and the other was hypothesized to be unaffected by human disturbance. Our goal was to determine how they differed in terms of spatial organization, behaviour and food habits. The populations were monitored using radio‐tagging. Squirrels in the park had significantly smaller home ranges than those in the forest. In both areas, they had multi‐nuclear home ranges, but the number of nuclei in the park was lower than that in the forest. This probably reflects more homogenous food availability (i.e. supplemental feeding). Squirrels in the park spent more time on the ground throughout the year than squirrels in the forest. This was probably related to their dependence on human‐supplemented food. Park squirrels often interacted with park visitors throughout the year – this involved approaching and taking food in 60% of the interactions. Hazelnuts and walnuts (food most often supplied by humans) dominated the diet of park squirrels, whereas pine and hornbeam seeds dominated the diet of forest squirrels. Overall, the study showed how living in the park with year‐round access to supplementary food changed the spatial organization and behaviour of red squirrels compared to that of the population from the urban forest reserve.

Target Species and Other Residents—An Experiment with Nest Boxes for Red Squirrels in Central Poland

“…In our study, red squirrels used nest boxes in all habitats but occupancy rates were highest in the urban park. This can be explained by the very high density of the red squirrel population in this area, driven by supplementary feeding [7]. The occupancy rates recorded in the urban park in our study (from a few to around 50% of the nest boxes available) were very similar to what was found in Great Britain (2 to maximum 53%) in a very abundant red squirrel population [12].…”

“…Squirrels are often fed nuts by visitors [46,47], and their population here reaches very high density (i.e., more 2 ind./ha, [13]). Squirrels occupy small home ranges and human-delivered food plays an important role in the diet of some individuals [7,8].…”

“…The species primarily inhabits forests [2] but can easily adapt to mild environmental changes. That is why the red squirrel can be found in natural areas [3], but also in small woods in agricultural lands [4], as well as in the city parks [5][6][7][8]. These last habitats are, according to some studies, potentially suitable refuges for red squirrels [9].…”

Body Condition and Breeding of Urban Red Squirrels: Comparison of Two Populations Affected by Different Levels of Urbanization

“…The Eurasian red squirrel ( Sciurus vulgaris L. 1758) has adjusted well to urban habitats [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. This species is strongly habituated to human presence, and its behavioural flexibility helps it to adjust to these specific conditions [ 28 ].…”

“…Urban habitats serve as suitable refugia for red squirrels [ 28 , 29 ], who are known to utilise urban structures [ 30 ] and move through built-up landscapes [ 31 ]. The abundance of red squirrels increases with human population density [ 29 ] and can be higher in cities than in rural areas [ 23 , 32 , 33 ]. Urban red squirrels can change their activity pattern [ 34 ], interact more with humans [ 23 , 24 ] and be bolder than their non-urban counterparts [ 35 ].…”