A dynamic model of hypothermia as an adaptive response by small birds to winter conditions

摘要: We present a dynamic programming model which is used to investigate hypothermia as an adaptive response by small passerine birds in winter. The predicts that there threshold function of reserves during the night, below it optimal enter hypothermia, and above rest. This decreases with particularly sharp drop at end representing time energy costs associated returning normal body temperature. results emphasise trade-off between predation, not just foraging options, but also day entering night. value being able use represents savings, reduced predation risk due changes strategy. Conditions give high are short photoperiod, variable food supply, low temperatures, poor scarce supplies.