Throughout a semi-natural experiment, we investigated seed use by two sympatric rodent species of different sizes, Apodemus flavicollis and A. sylvaticus, focusing on how Quercus cerris acorn mass affected seed predation, removal and dispersal by mice. A total of 20 adult A. flavicollis and 25 adult A. sylvaticus were individually tested in an open-air experimental enclosures. 40 Q. cerris acorns were collected in the same forest where the rodents had been cought and were then weighed with a digital balance (to the nearest 0.01 g) and individually marked with a univocal alphanumeric code written on the seed shell surface. Each test started when we placed the 40-acorn sample on the ground at the center of the enclosure and lasted for three consecutive days. At the end of the test, the final seed fate of each acorn or acorn leftover were recorded and classified as: (1) eaten (partially or completely) in situ (i.e., center of the enclosure), (2) not eaten in situ, (3) removed and eaten (partially or completely), (4) removed and not eaten (i.e., seeds that potentially could have been successfully dispersed). Animals were released at their capture site at the end of the tests, after three days of captivity. We used generalized linear mixed models (GLMMs) with binomial distribution (family = binomial, link = logit) to investigate the relationship between acorn fate and acorn mass and to estimate the probability of a rodent specific response pattern (i.e., foraging strategy) to seeds. The individual seed was considered as a sampling unit and seed fate was modelled as a binomial variable. We structured four models for foraging strategy and final acorn fate: a predation model (binary data: 0 = not eaten, 1 = eaten), a removal model (0 = not removed, 1 = removed), a site-specific predation model (0 = eaten and not removed, 1 = eaten and removed), a dispersion model (0 = removed and eaten, 1 = removed and not eaten). In the GLMMs, the individual rodent was included as a random factor, rodent species as categorical factor and acorn mass as covariate with an interaction term. To evaluate interspecific differences in foraging strategies, we estimated marginal trends from the GLMMs, enabling direct comparison of acorn mass effects on seed fate between species while maintaining model integrity. To account for potential nonlinear effects of seed mass on removal observed in the raw data we included a quadratic term for acorn mass to test for unimodal patterns in seed removal. Given the difference in body mass between individuals of the two rodent species we tested, rodent body mass was also included as a covariate in the removal model to account for individual variation in handling ability. Finally, to assess interspecific differences in the mass of removed acorns, we used linear mixed models (LMMs), with the individual rodent included as a random factor and rodent species as categorical factor. We applied the same model structure to test for differences in the acorn mass to rodent body mass ratio associated with removed acorns. We detected a species-specific response in seed predation: A. flavicollis was more likely to predate heavier acorns, while seed mass had no significant effect on the probability of seed consumption for A. sylvaticus. Removal probability did not differ between species suggesting similar removal patterns with respect to seed mass across species, which were more likely to remove intermediate-sized seeds. Apodemus flavicollis removed acorns with a seed mass to rodent mass ratio significantly lower than the one observed for A. sylvaticus. After removal, the likelihood of predation versus that of dispersal resulted to be species-specific. Specifically, it did not vary with seed mass for A. flavicollis, while A. sylvaticus tended to disperse heavier acorns. These findings suggest that the two species might play distinct roles in determining seed fate.