Some migratory birds are heterothermic, meaning they sometimes maintain a constant body temperature and other times allow their body temperature to vary, for example, on cold nights, they sometimes reduce their metabolic rate and allow their body temperature to drop as the air temperature falls. which of the following hypotheses about this unusual strategy is consistent with what you learned in this section? birds allow their temperature to drop in order to increase their assimilation efficiency o birds allow their temperature drop in order to increase their production efficiency birds allow their temperature to drop in order to increase their consumption efficiency.