Cache like a Squirrel: Effects of Long Term Storage on Crude Fat Content of Q. Palustris and Q. Alba Acorns

Quercus palustris and Quercus alba acorns are a primary component in many wild animal diets, particularly during preparation for winter. As such, they provide a natural, easily gathered food staple for wildlife recovering in rehabilitation facilities. We examined whether collection and temperature-controlled storage methods differentially affect the nutritional deterioration of crude fat in acorns to assess both caching by wildlife and to provide recommendations to rehabilitators. We collected acorns from Q. palustris in 2020 (N=8) and Q. alba in 2017 (N=11) in Bridgewater, VA, USA. Acorns were dried for 7 days using a fan or for 30 minutes in an oven at 93°C and then stored at room temperature hanging in onion bags, in the refrigerator, or in the freezer. We assayed fat content from all trees immediately after collection (baseline) and compared fat content after one month and six months of storage for both species. Storage at 4°C (refrigerator) resulted in germination of some Q. alba acorns and mold growth in both species. Although acorns from Q. palustris had significantly more fat than Q. alba acorns, individual trees varied widely, with greater variation among Q palustris. On average, drying, storage, and combination treatments resulted in greater losses in fat compared to baseline for Q. alba than Q. palustris, but not significantly. Our results suggest that acorns cached by species like squirrels (Sciurus sp.) do not vary significantly in fat content when recovered months later compared to acorns consumed directly from the trees. We recommend wildlife rehabilitators store acorns either in the freezer or at room temperature depending on their storage capabilities.