Seasonal activity patterns of sympatric eastern gray squirrels (Sciurus carolinensis) and fox squirrels (Sciurus niger) in a Midwestern metropolitan region

Larson, Rachel N.; Sander, Heather A.

doi:10.1007/s11252-022-01245-4

Cited by 3 publications

(1 citation statement)

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“…This may be due, to some extent, to the ‘urban heat island effect’, where air temperatures are higher in urban compared to surrounding areas (Imhoff et al 2010 ), allowing animals, especially small bodied species, to remain active for prolonged periods in winter. For example, gray squirrels start foraging earlier in the day in areas with high impervious surface cover (i.e., urban areas) compared to in areas with low impervious surface cover (Larson and Sander 2022 ), potentially because of warmer ambient temperatures caused by impervious surfaces which would reduce some of the metabolic costs associated with activity at low ambient temperatures. Moreover, anthropogenic food sources are readily available in urban habitats (Oro et al 2013 ; Plaza and Lambertucci 2017 ), and access to these resources has generally been reported to positively affect body condition via increases in body mass (Andrzejewski et al 1978 ; Otali and Gilchrist 2004 ; Schulte-Hostedde et al 2018 ).…”

Section: Discussionmentioning

confidence: 99%

Gray squirrels consume anthropogenic food waste most often during winter

et al. 2022

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Urban habitats provide wildlife with predictable, easily accessible and abundant food sources in the form of human food waste. Urban eastern gray squirrels ( Sciurus carolinensis ) are commonly observed feeding in trash bins, but we lack data regarding the type, quantity and seasonal changes in food waste usage. We observed five trash bins on an urban university campus during four different observation periods. We recorded the time squirrels spent on and inside trash bins and type of retrieved food items. We also recorded ambient temperature, human presence and trash bin filling. Moreover, we determined changes in squirrel population density in a natural and three anthropogenic habitats during the same periods. Trash bins were fuller when human presence was higher. The higher human presence, the more squirrels went on and inside the bin, but there was no effect on number of retrieved food items. Trash bin usage by squirrels decreased when ambient temperature and bin filling increased. Most food items were retrieved during the coldest observation period, a period of high human presence, and the majority of retrieved food items were starchy foods (e.g., bread, French fries). The relationship between the number of squirrels observed along transects and a measure of urbanization, the normalized difference built-up index, was negative in periods with high ambient temperatures and positive in periods with low ambient temperatures, indicating winter may be less challenging in urban areas, likely facilitated by the availability of anthropogenic food sources, allowing a higher level of activity throughout winter. Supplementary Information The online version contains supplementary material available at 10.1007/s42991-022-00326-3.

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