How Birds Beat the Heat

Thursday, July 1, 2021

Summer is officially here, and the temperatures are soaring. To help us beat the heat, humans have the biological ability to sweat, which helps cool the blood beneath our skin. Most of us are also able to retreat to the cool safety of our homes where we have fans and air conditioning units. Birds, on the other hand, lack the ability to sweat and can't fit an air conditioner in their nests. Instead, birds have evolved a variety of physical adaptations and behavioural techniques to help them cool down when things heat up. 

Gray Catbird cooling off in a birdbath

Physical Adaptations

  • Higher body temperature: Birds have an advantage in the heat of having an operating at a higher body temperature than humans (birds average 40℃; humans average 37℃). This small difference in temperature may seem insignificant, but their slightly higher body temperature helps birds feel the heat less intensely than we do. 

  • Rapid respiration rate: The rapid rate at which birds inhale and exhale allows for heat to be transferred out of the body through the lungs. This is possible through regular breathing, without the need for opening their bills or "panting".

  • Bare skin: We know from experience that showing some skin in the summer helps us to keep cool, and it works for the birds, too. Exposed skin such as on the face, legs, and feet, allows heat to dissipate at a greater rate than areas covered in insulating feathers. The smallest areas of bare skin, like a fleshy eye ring or bit of skin around the bill, can help release heat from the body on hot days, and some birds can even swell these areas to help cool down more quickly. 

Cedar Waxwing practicing gular fluttering

Behavioural Techniques
  • Gular fluttering: This technique is one that resembles panting that you would see from a dog or cat, but is a method that is a little more intense. When a bird engages in gular fluttering, it first opens its bill widely, and "flutters" the muscles in the throat (gular muscle) while breathing rapidly. This action helps to carry heat out of the body quickly through the lungs and air sacs, while bringing in cool air to help regulate body temperature. 

  • Bathing: There's nothing like a dip in the water on a hot summer's day, and birds agree. Sometimes simply walking through water and getting their bare legs wet will be enough to provide relief from the heat, while other times may call for a full body plunge to cool down. Most backyard songbird species will take advantage of a shallow birdbath with 1-2" of fresh, clean water to bathe in and drink from. Adding a mister or dripper can help attract even more species to your birdbath, and helps keep algae growth to a minimum. 

  • Spreading feathers: Feathers are great for helping keep birds warm in the winter, but can be an issue in extreme heat. When a breeze blows on a hot day, birds will puff out their feathers to allow the air to get to their hot skin, and may also hold their wings out to allow for even more air circulation. 

  • Soaring: Birds who are able to soar at higher altitudes, such as birds of prey, take advantage of the cooler temperatures up in the sky and will spend much of the day riding the breeze. 

  • Activity level & timing: If you feed birds, you may notice that on particularly hot days you see less activity through late morning and early afternoon, the warmest periods of the day. When possible, birds will choose to forage and feed when the heat is less intense, typically early morning and late afternoon to evening, in order to help keep cool and expend less energy.

    *Fun fact: Some birds (Turkey Vultures, mainly) go the extra mile to cool down when temperatures rise in an act called urohydrosis, where they urinate on their bare legs. The urine itself helps cool the skin, and the white residue left from the urate reflects sunlight to help provide some extra relief. 

Northern Flicker spreading its feathers to cool down in rainfall - Photo by Pat Plewman

You can help birds keep cool in your backyard by offering fresh and clean water at all times, creating shaded areas by growing a variety of native plants from small shrubs & ground covering plants, to tall trees, and by offering high-quality foods to help get them through heatwaves and exert less energy while foraging. Lastly, act on the climate crisis threatening our bird populations. In our ever-warming climate, birds are having to adapt and find new ways to cope with extreme heat at an accelerated rate. Of course - just as with all species - there is only so much adaptation that can be done in a short amount of time before heat and extreme weather causes a collapse in their populations. Scientists have been documenting the affects of climate change on birds for many years and have found that birds are laying eggs earlier, migration times are shifting, their behaviour isn't lining up with seasonal shifts in the environment, species distribution and range is changing, and vulnerability and extinction rate is on the rise. Making small changes in your own home & yard such as cutting back on the use of plastics, eliminating pesticide use, shrinking your lawn space, and growing native plants, can have a huge impact on our environment and wildlife species. 

Happy trails!
- Shayna 

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