“It seemed like it was probably almost a decade during the hot summer time when my students came back into the building and knocked on my door and said, ‘Hey, did you see the lovebirds on the windows and vents? ‘I would say, “Yes, I have.” And they said, ‘What do you think they are doing? Why are they here? Maybe they cool off or avoid something. ‘And I said,’ That sounds really interesting. Maybe we should do a study on it. ‘”
Arizona State University biologist Kevin McGraw usually studies the way animals, including birds, use color as a means of communication. But he couldn’t resist the bird secret right outside his office door. After hearing about the birds on campus year after year, he decided to enlist the help of a few students to find out what they were up to.
Rosy-faced lovebirds are a species of parrot that is native to arid parts of southwest Africa such as the Namibian desert. Probably because of the pet trade, it was founded in Phoenix, Arizona about 35 years ago. In their homeland, they usually stick to natural areas, but in Phoenix they seem to prefer urban areas like the ASU campus.
“It’s the hottest city in North America here in Phoenix, and there aren’t many micro-locations in the desert to hide in, or in this case, cool off.”
Some of the older buildings on campus have inefficient cooling systems that release cooled air to the surrounding area. It’s bad for energy efficiency, but good for the birds.
Although pink lovebirds live in Phoenix year-round, the researchers found that they only visit air conditioning vents between June and October. And they most likely do it on the hottest days that exceed 99 degrees Fahrenheit. The results were published in the journal Biology letters. [Raegan Mills and Kevin J. McGraw. Cool birds: Facultative use by an introduced species of mechanical air conditioning systems during extremely hot outdoor conditions]
Even this desert-adapted bird has a thermal tolerance limit, and the sultry Phoenix summer – exacerbated by the urban heat island effect – often exceeds it.
Obviously, these aren’t the first animals to use the built environment. For example, many birds look for buildings to nest or sleep in. In these cases, the built environment replaces a natural habitat that has disappeared.
That’s not quite what’s happening here, says Raegan Mills, an ASU student who led the study.
“It wasn’t that they only moved into these rooms because the previous rooms that were there had been taken away. It was: You will find this interesting new opportunity to fulfill some kind of thermoregulatory function. “
The researchers say this may be the first formal documentation of an animal population using building infrastructure for cooling.
“The big advantage lies in our human responsibility when it comes to rising global temperatures. We’re pushing these animals to adapt to it in really novel, interesting ways. Wild birds usually don’t like being around people. “
Once the pandemic restrictions allow them to return to campus, Mills and McGraw hope to continue their investigation into these birds. One thing they would like to understand is whether the introduced lovebirds are competing native birds for access to this cooling resource, or whether native species have found other strategies to survive the hottest days.
“I think we have a pretty significant moral responsibility to understanding how we get animals to interact with us.”
– Jason G. Goldman
[The above text is a transcript of this podcast.]