Cold wet weather is the worst condition for martins to survive because flying insects typically become inactive when the temperature drops below 48º F which completely cuts off their food supply. Martins are also highly susceptible to hypothermia, or abnormally low body temperatures, and may die of exposure after several days of extremely cold weather. Martins try to conserve body heat by clustering together in a single cavity or two and remaining inactive. This helps them to conserve their energy which is vital for their survival during these times of severe cold. Martins on the interior of this cluster are more likely to survive than the ones on the outside which may still succumb to exposure.