Grand designs Galah style: excavation of a nest hollow in a hardwood tree from scratch.

Most members of the Psittaciformes (parrots and cockatoos) are obligate hollow nesters, breeding in existing hollows in trees. The Galah Eolophus roseicapilla is a species endemic to Australia, and typically breeds in existing hollows. In May 2024, a pair of Galahs in a suburb of Canberra, Australia's capital city, commenced excavating a hollow in a hardwood tree (Eucalyptus mannifera) in the front yard of a house. Over the next 15 months, they continued their excavations until they created a hollow that was 640 mm deep with a floor that was a flattened oval in shape, measuring 272 mm long and 138 mm at the narrowest. During their excavations, Common Brushtail Possums Trichosurus vulpecula tried to usurp the hollow, but the owners of the house where the tree was located evicted the possums. In August 2025, the Galahs laid four eggs, hatched three, and fledged one nestling in November. This is the first documented record of any species of Psittaciformes excavating their nest hollow from scratch in a hardwood tree. [ABSTRACT FROM AUTHOR]