Given a choice, urban Australian white ibis prefer carbohydrates over their more natural diet, according to new research that could provide insights into why they are moving to the city.
The urban Australian white ibis has become something of a celebrity following significant online and social media attention, including a recent spoof video that captured its less-than-gourmet food preferences.
Traditionally found in large populations throughout inland wetlands in Australia, ibis are a relatively recent arrival in urban Australian landscapes. Now generally considered pests, they’re often found scavenging for human food in garbage dumps, bins and on picnic tables.
Many consider the bird willing to eat anything but it seems ibis have distinct food favourites. New research published in Behavioral Ecology shows the bird has a strong preference for high-carbohydrate foods, despite their natural diet typically being low in carbohydrates and higher in protein and fat.
Lead author Sean Coogan, a PhD student at the University of Sydney’s Charles Perkins Centre and School of Life and Environmental Sciences, said the findings suggest ibis forage for macronutrients rather than energy per se.
“Urban Australian white ibis seem to be taking advantage of the abundance of high-carb human foods available in the city,” he said
“It could be a situation similar to humans, where we have a preference for high-carb foods perhaps because those foods were relatively rare in our ancestral diets. In current times, humans have created a food environment with an abundance of cheap high-carb foods, seemingly to the detriment of our health."
We don’t know what effect the human foods have on ibis, which could be a focus of future research. But on the surface, ibis seem to be doing pretty well in the city, as evidenced by their population growth and breeding success.
The birds tend to eat more of their less preferred high-fat foods when feeding in large groups. Weather conditions also had an effect, with ibis increasing the amount of protein and fat they consume after rainfall.
“We believe the ibis could represent a valuable model for examining the nutritional characteristics of highly successful urban wildlife. These findings could have broader potential to help us understand the nutritional dynamics of other animals living in urban areas and alongside humans – which is important given the growth of the human population and increasing urbanisation.”