Optimizing Fat Reserves over the Entire Winter: A Dynamic Model

During winter, energetic expenditure is high, day are short, and food is often scarce. Many small birds cope with winter weather by daily depositing rat reserves approximately equal to the amount of energy they will expend the following night. We modelled fat reserve levels for small birds over a 100-day winter. We assumed that: a) Expected energetic requirement was greatest in nindwinter, mimicking long, cold nights. b) Energetic requirement varied around the expected value. c) Food was always available but feeding entailed a predation hazard