As the heat of July settles in on Metinic, our birds, especially all those chicks we have, all need ways to keep cool.
Like humans, birds need to keep their bodies at a specific temperature. However, birds lack one of the key ways humans keep cool: the ability to sweat . So how does an animal covered in feathers and/or down make it through the summer without suffering from heatstroke? (No, the answer isn’t air conditioning or lots of ice cream)
This isn’t that hard for swimming seabirds like Common Eiders. Even though these ducklings are dressed in down coats for the summer, they don’t run the risk of overheating because they hop straight in to the cold coastal waters, sometimes on the day they hatch! Adults and ducklings alike will spend almost all their time in the water, occasionally hopping up onto rocks to preen.
However, chicks that aren’t ready to swim on day one can’t just jump in the water for a nice cool dip. Black Guillemots have found one of the simplest solutions to keeping their chicks comfortable – keep them out of the sun. Along with providing protection from hungry gulls, a guillemot’s burrow is shaded and cool. The chicks won’t leave the burrows until they are ready to swim, and then they can chill like the eiders.
So what if you’re stuck on the land, without a shady burrow like, say, a tern chick? You start out getting a little help from mom and dad. When tern chicks are small enough, they can be brooded by their parents. This behavior does double duty: it keeps chicks warm on cold nights and mornings, and provides cool (or at least cooler) shade during hot days.
Some chicks still seem to want to be brooded even when they are far too big.
If the parents are off fishing, something they spend most of their time doing once the chicks are a bit bigger, the chicks have to keep themselves cool. The simplest strategy is familiar to anyone with a pet dog: panting. Adults and chicks alike can be seen panting on hot days.
Once mobile, usually just a few days after hatching, tern chicks can seek out shade on their own by escaping under a rock or into the cooler grass. It isn’t unusual for us to find “chick tunnels” marking the path chicks take back and forth between their nests (where they get food from their parents) and a safe spot in the grass. We also put out three-sided structures known as “chick huts” in more exposed areas without much natural shelter.
Hope all our readers are staying cool as well!