Humans aren’t the only creatures that sometimes like a soggy snack: researchers have discovered that some cockatoos also submerge their food before eating.
The team says they first noticed captive Goffin’s cockatoos feeding their meat in a lunch, just like some people dip cookies in their tea, and decided to explore further.
Write in the journal Biology Lettersdescribe researchers at the University of Vienna how they placed the birds’ food – twice-baked bread known as rusks, dried pieces of fruit, seeds and bird pellets – in bowls inside their aviary in the presence of bowls of water.
Over the course of 12 days, the team recorded which birds dipped, what the dipped item was, how long it was dipped, and whether it was eaten afterward.
Overall, the team found that seven out of the 18 cockatoos dipped their food at least once, with biscuits the most popular item. Two of the most prolific dunkers have shown that crackers are best eaten wet. Dried banana chips and desiccated coconut chips were also occasionally dipped in water, but the duo tended to prefer them dry.
“The behavior was apparently directed mainly at rusks, a dry and hard type of food that easily absorbs water and takes on a soup-like texture,” the team writes.
The researchers found the seven cockatoos showed considerable variation in how long they left their pieces of rusk in the water, although some left them long enough for the core to soften – according to the team’s own rusk-immersion experiments.
The team says the lack of live prey rules out the possibility that the birds tried to drown their food, while freely available water makes it unlikely that they dived to rehydrate.
“Scenting behavior also seems unlikely as they dip food in fresh, unscented tap water,” they write, adding that the birds’ pickiness about which foods they dipped suggests they did not attempt to wash the food.
As a result, the team says the birds likely dipped the rusk to soak it, a strategy they say can improve the texture.
The researchers say the behavior requires impulse control and delayed gratification, and highlights the resourcefulness of the birds in a food preparation context.
“Because only some individuals dived for food and were not dived in the wild, we believe that foraging is a spontaneous innovation, either by one or more individuals,” they write.
Prof Simon Reader from McGill University in Montreal, who was not involved in the study, but worked on immersion by wild Carib birdssaid it was surprising that the behavior had not been scientifically documented in parrots before.
“We found that the dive was very rare in the wild in the Caribbean grasslands, but it was less innovative than we thought – almost all birds can do it if you put them in perfect conditions, with dry food, water and road of the risk of the food being stolen,” he said.
“Like these parrots, dunking seems to be something they use depending on the costs and benefits at the time.”
