Table 2.

Parameter values

Symbol	Parameter	Value
X max	Max body fat depositsa	148 kJ (4 g fat, 100 discrete steps)
Y max	Max degrees hypothermiab	7 °C (20 discrete steps)
D	Number of days in winter	100
T	Number of time periods in winter	288,896 (288 × 100 + 96)
γ	Increase energy expenditure cold weather	20%
δ	Reduced energy gain unsuccessful foraging	20%
ε	Reduced energy expenditure max hypothermia	30%
x start	Fat deposits start of forward iteration	12 kJ
C WUi	Extra warming up cost hypothermic birds	0 or 6 kJ

^aCeiling of the model, much more than the model ever predicts any bird to carry

^bThe unit for hypothermia in the model is % save of resting metabolism. The maximum save (30%) is translated to 7 °C to facilitate reading of the figures