|Tower Girl cools down using "gular fluttering."|
As Central Texas moves deeper into the summer months, we Austinites like to find relief from the oppressive heat by wearing shorts and t-shirts, consuming cool drinks, and ducking inside air-conditioned spaces. If you have been watching our resident Peregrine falcon, Tower Girl, you might also see her coping with the heat, albeit sometimes in ways different than we do.
Birds naturally have high body temperatures and their feathers are remarkable insulators. So, dissipating heat is important for a bird’s health.
As birds do not have sweat glands, they cannot find relief by sweating. Contrary to popular notions, they also don’t pant like dogs do. What we might think of as panting is actually “gular fluttering.” The bird opens its mouth and “flutters” neck muscles which promotes heat loss. The act of a dog panting actually causes the dog to lose a lot of fluids, but fluttering is much more efficient at preserving body fluid loss.
As the photo of Tower Girl show, birds also expand their wings to cool off, or they fluff their feathers. This allows air to reach their skin. It’s very much like how we repeatedly pull on our shirt collars to move air across our skin.
According to a study on marsh sparrows in 2011, a bird’s bill size correlates with the ambient temperatures. A larger bill allows blood flow to increase or decrease, which promotes or prevents heat loss, so birds living in warmer climates have larger bills.
Birds also keep their high-energy activities like food seeking mostly in the mornings and evenings, when it is cooler. However, some birds actually fly in the cooler high altitudes to find relief.
Much like us however, birds love a water source and they love shade. With Tower Girl spending quite a few afternoons in her shady north-facing nest box, she is able to dodge these oppressive Austin days of summer.
Bové, Jennifer. “Nature Q&A: How Do Birds Stay Cool in the Summer?” August 25, 2010. National Wildlife Federation. Accessed online May 15, 2018 (http://blog.nwf.org/2010/08/nature-qa-how-do-birds-stay-cool-in-the-summer/)
Griffin, Catherine. “How Birds Keep Their Cool” August 01, 2012. Audubon. Accessed online May 15, 2018 (https://www.audubon.org/news/how-birds-keep-their-cool)