Europe is experiencing extreme heat with high temperatures and humidity. "Prolonged intense heat like Europe is experiencing right now is likely pushing many species toward their maximum heat tolerances, putting them at risk of heat illness or death," said Aimee Van Tatenhove, a postdoctoral fellow at the Cornell Lab of Ornithology.

"This level differs by species, and as you can imagine, species that live closer to the poles are often much more susceptible to heat than species that live closer to the equator," Van Tatenhove said. Birds have a higher body temperature than mammals, with some species maintaining body temperatures around 38 degrees Celsius (100 degrees Fahrenheit) or higher. To regulate their temperature, birds may adjust their feathers or increase airflow across air sacs.

To cool themselves, some bird species open their beaks and pant, a behavior known as gaping. Others flutter the pouch skin on their necks, a behavior called gular fluttering. Birds often seek out shade and use water sources such as birdbaths, fountains, and shallow ponds to lower their body temperatures. They also find lower places to perch or use fans to escape the heat.

Birds provide various ecosystem services, including pollinating flowers, controlling pests, dispersing seeds, and serving as early warning systems for environmental changes. Insect populations, a natural food source for birds, have declined due to factors such as climate change and pollution. Jack Kottwitz, an assistant professor at Michigan State University's College of Veterinary Medicine, stated, "These birds know better than what we do about what is comfortable for them." David Bird is an emeritus professor of wildlife biology at McGill University.