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Tree Squirrels Selectively Disperse High-Quality Acorns Away From Tree Trunks
Miguel Puente-Ruiz1,2, Raquel Muñoz-Gallego1,2, Marta Peláez1,2,3
1Departamento de Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, Madrid, Spain.
Integrative Zoology
|July 23, 2026
Summary
Eastern fox squirrels (Sciurus niger) selectively disperse high-quality acorns away from trees, promoting oak regeneration. Their foraging behavior and seed selection influence oak recruitment and woodland expansion.
Area of Science:
- Ecology
- Zoology
- Botany
Background:
- Seed dispersal by rodents is crucial for oak regeneration.
- The combined effects of seed quality and squirrel foraging on dispersal patterns are not well understood.
Purpose of the Study:
- To investigate how the Eastern fox squirrel (Sciurus niger) affects the dispersal of Quercus agrifolia and Quercus lobata.
- To understand the influence of acorn quality (weight, infestation) and foraging behavior on dispersal patterns and post-dispersal fate.
Main Methods:
- Acorns were tagged and offered at camera-monitored stations.
- Dispersal distances were measured relative to supply stations and tree trunks.
- Acorn quality, embryo excision, and post-dispersal fate were assessed.
Main Results:
- Heavier acorns were dispersed farther; non-infested acorns were preferentially embryo-excised and dispersed more than infested acorns.
- Acorns consumed near tree trunks indicated feeding in refuges, while intact/excised acorns were moved farther to avoid pilferage.
- Quercus lobata acorns, being more nutritious, were more frequently embryo-excised and dispersed farther than Quercus agrifolia acorns.
Conclusions:
- Eastern fox squirrel acorn dispersal is context-dependent, influenced by seed quality, tree proximity, and foraging behavior.
- Selective transport of high-quality acorns away from trees by squirrels enhances oak recruitment and woodland expansion.
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