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Seeds are an important food resource for many rodents, but the decision to consume or cache seeds when they are encountered can be influenced by numerous factors such as their abundance, nutritional value, and plant secondary compound (PSC) contents. Although previous studies on rodent foraging behaviors have focused on the effects of specific seed characteristics, the combined impact of seed quality and abundance is unclear. Here, we used artificial food patches in the field to examine the foraging behaviors of deer mice (Peromyscus maniculatus) in response to varying abundances of high-- and low--nutritional-quality conifer seeds. We also used a variant of giving-up densities to assess mouse perception of the quality of seeds in patches. Mice treated white spruce (Picea glauca) seeds as a high-quality food source in the field, whereas subalpine fir (Abies lasiocarpa) seeds were treated as low quality, corresponding to their nutrient and PSC contents. Observations of foraging behaviors showed a strong interaction between seed abundance and quality on foraging decisions. Caching, but not consumption, rates of spruce seeds varied with seed abundance, but abundance did not influence the frequency or nature of use of fir seeds, which were mostly ignored. High abundance did not confer any value to fir seeds, and even when exaggeratedly abundant relative to naturally available seed densities, mice almost completely disregarded these low-quality seeds as a valuable resource for both current and future use. Our results highlight the relative importance of seed quality in this foraging interaction. [ABSTRACT FROM AUTHOR]

The cache decisions of scatter-hoarding animals are influenced by a number of factors, including satiety, food quality, number of competitors, and the risk of predation and pilferage. However, it is unknown how animals assess these variables. We investigated this process experimentally in free-ranging fox squirrels (Sciurus niger) by measuring the effects of nut characteristics and social context on nut-handling behavior and subsequent cache decisions. We found that a behavior involved in nut handling, the head flick, was correlated with nut quality, shell presence, the decision to cache rather than eat the nut, and the time and energy spent caching. In contrast, a 2nd nut-handling behavior, the paw maneuver, was correlated with the social context but not the cache decision, and may instead reflect a response to social competition. Our results suggest that fox squirrels assess nut quality using overt, observable nut-handling behaviors. The experimental study of these behaviors can help us understand how animals use information about food and the social context to make adaptive food-storing decisions. [ABSTRACT FROM AUTHOR]

We hypothesized that caching could be a mechanism to remove volatile secondary compounds from a plantbased diet. This mechanism has been demonstrated in 1 herbivore and has been hypothesized as a widespread mechanism for reduction of intake of toxins. We examined this hypothesis in both the field and the laboratory by documenting the ability of herbivorous rodents to manipulate alpha-pinene, the major terpene in juniper (Juniperus osteosperma). First, we dismantled middens of Neotoma albigula and found that cached plant material was devoid of alpha-pinene, whereas surrounding trees contained alpha-pinene. In laboratory trials, we examined the ability of woodrat species (N. albigula, N. lepida, and N. bryanti) to reduce toxin intake by storing food before consumption. Each species responded differently when offered terpene-treated pellets. N. albigula controlled terpene intake by increasing reliance on the terpene-free cache. N. lepida controlled terpene intake by decreasing total intake but did not change cache consumption. N. bryanti did not regulate terpene intake. All 3 species abandoned more food in the foraging cage when the food contained terpene. In an additional laboratory trial with N. albigula, we determined that increased abandonment was not related to cache size. [ABSTRACT FROM AUTHOR]