The Heat is On

The National Weather Service is predicting a string of near 90 degree weather for the next four days. Not good news for the loons. The common loon is a northern species, adapted to relatively cool summers. Their thermoregulation system is better suited to conserving heat rather than dissipating heat. New Hampshire is on the southern edge of the loon’s range and, although the trophic status of the lake (chlorophyll, phosphorous, turbidity) plays a large part in determining habitat suitability, climate has an important role in controlling trophic status as well as challenging the loon’s heat tolerance. This is especially true for adults incubating eggs because they no longer have the cooling effect of being immersed in water.

You will see a lot of panting by the nesting loons, the same cooling mechanism that dogs use. During the hottest times of the day a loon is apt to take a short dip in the water to cool off. The time off the nest is usually no more than 10 to 15 minutes. On the hottest days, an egg exposed to direct sunlight can overheat and become inviable within a half hour. LPC has been experimenting with various nest raft coverings to provide shade on the raft while still allowing visibility for the loon in all directions. If the climate model projections are accurate, New Hampshire’s loons will face increasing climate challenges over the next few decades.