A new study shows how migratory songbirds can change their breathing patterns to fly at high altitudes which, due to climate change, could become a necessity.
The research, from Western University’s Advanced Facility for Avian Research (AFAR), is the first to show that birds adjust their physiology during the migratory season to maintain oxygen uptake and movement to flight muscles, with some species able to make greater adjustments than others.
"Climate change is going to continue heating up the environment and birds need to fly so they can migrate and breed," said Chris Guglielmo, AFAR co-director and senior author on the study.
Like everyone else, birds are enduring changing temperatures, changing humidity, and even wildfire smoke due to climate change.
"This study shows they need to fly in higher altitudes – and some of them can – to stay in cooler environments or they’re not going to survive," Guglielmo noted.
Using a unique hypobaric climatic wind tunnel, researchers investigated how some songbirds could adjust their bodies to inhale and distribute oxygen to blood vessels and flight muscles during the migratory seasons compared to non-migratory conditions.
Banting postdoctoral fellow Catherine Ivy said she was able change the air pressure in the wind tunnel to simulate the birds flying higher and higher. This allowed her to assess how the changes in oxygen uptake and transport would allow these birds to fly at high altitudes.
"Basically, I wait to see at which point flying becomes more difficult for these birds," Ivy said.
"We have discovered that not all songbirds use the same strategy to enhance oxygen uptake and movement to the flight muscle during the migratory season," she added.
Yellow-rumped warblers, a common bird in southwestern Ontario, were particularly good at this exercise. Ivy said this was surprising, "as this species only migrates for 6-8 hours at a time, so we predicted they would not fly very high."
Thrushes, equally common to the area, did not show similar changes in this study and will be further investigated this fall.