Lead author Antone Martinho of Oxford's Department of Zoology said, "It seems surprising at first that these one-day-old ducklings can learn something that normally only very intelligent species can do; it also makes biological sense. When a duckling is young, it needs to be able to stay near its mother for protection, and an error in identifying her could be fatal."
"Ducks walk, swim and fly, and are constantly changing their exact shape and appearance as they extend their wings or become partially submerged, or even change angle with respect to the viewer," he continued. "If the ducklings just had a visual 'snapshot' of their mother, they would lose her. They need to be able to flexibly and reliably identify her, and a library of concepts and characteristics describing her is a much more efficient way to do so, compared with a visual memory of every possible configuration of the mother and her environment."
"Still," Martinho concluded, "this is an unexpected feat for a duckling, and a further reminder that 'bird-brain' is quite an unfair slur."
WATCH: Do Animals Dream Like Us?