Captive Goffin's cockatoos found to dunk hard bread to improve its texture

A pair of veterinary medicine researchers at Medical University of Vienna and University of Vienna, in Austria, has found that some captive Goffin's cockatoos prefer to dunk their hard bread before eating it, seemingly as a means to improve its texture. In their paper published in the journal Biology Letters, Jeroen Zewald and Alice Auersperg, describe their observations of the birds and their theories on why the birds dunk the bread.

Many animals have been observed dunking food in water before consumption—raccoons are a prime example. Prior research has shown that at least 25 species of birds dunk food in water before consumption, though why they do so has remained unclear.

In this new effort, the researchers working at the Goffin Lab at the University of Veterinary Medicine Vienna discovered by happenstance that some of the birds in the lab carried pieces of rusk to a nearby water bowl and dunked it for several seconds before consuming their treat. Rusk is a type of twice-baked, dry and brittle bread that is commonly given to teething babies. In this instance, it is given to captive Goffin's cockatoos as part of their daily rations at the lab.

The researchers report that they happened to note that one of the birds, a male named Pippin, picked up a piece of rusk and headed to a nearby water bowl, normally used for bathing. Once there, he pushed the bread piece underwater and held it there for several seconds. He then pulled the snack from the water and ate it.

Intrigued by their observation, the researchers began to watch more closely as the birds were given their food—the rusk was served along with seeds, bird pellets, dried fruit and cornflakes. As they watched, the researchers noted that several of the birds mimicked the actions of Pippin, though they varied in both dedication and the amount of time they dunked the bread.

After watching the birds eat over a 12-day period, the researchers noted that 7 of the 18 birds in the lab dunked their food—and it was almost always rusk. The birds left the bread in the water for an average of 23 seconds, more than enough time to soften its texture. They also found that some of the birds were willing to go to great lengths to soak their bread before eating it, such as climbing ladders and moving things out of the way.

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