Does caching strategy vary with microclimate in endangered Mt. Graham red squirrels?

Area of Science:

• Behavioral Ecology
• Conservation Biology
• Wildlife Science

Background:

• Food hoarding is a crucial survival strategy for many animals facing food scarcity.
• Relict populations at species' distribution edges face unique environmental stressors that can impact behaviors like hoarding.
• Understanding hoarding behavior variability is vital for the conservation of endangered species like the Mount Graham red squirrel.

Purpose of the Study:

• To investigate the variability in food caching behavior of the endangered Mount Graham red squirrel (Tamiasciurus fremonti grahamensis).
• To assess how microclimate, soil relief, vegetation, food availability, and squirrel sex influence caching decisions.
• To determine the adaptive significance of hoarding behavior in a stressful, changing environment.

Main Methods:

• Quantified cache size by counting excavated pits as a proxy for cached food volume.
• Analyzed the influence of environmental variables including mountain slope aspect, tree density, and midden microclimate.
• Compared caching behavior between male and female squirrels and assessed sex-specific responses to environmental factors.

Main Results:

• Cache size was significantly affected by mountain slope aspect and tree density.
• Northeast-facing slopes showed more caching pits, while tree density negatively impacted caching on southwest slopes.
• Males cached significantly more than females, and sex-specific responses to slope aspect were observed. Caching behavior was not influenced by midden microclimate.

Conclusions:

• Hoarding behavior in Mount Graham red squirrels is influenced by landscape features and sex, indicating adaptive plasticity.
• The lack of response to microclimate variation may pose risks to squirrel survival amidst predicted regional warming.
• Conservation strategies for this endangered species should consider these behavioral adaptations and environmental sensitivities.