Both birds take turns to incubate the eggs with a changeover every few hours. The bird not incubating goes to feed nearby if possible and keeps a look out for predators. From time to time you may hear that bird alarm calling from a distance when it senses danger. The alarm calls are shorter and more staccato than the familiar ‘bubbling’ call. You can also hear the birds communicating during a changeover.
The adult male is smaller than the female with a shorter bill.