3D-printed eggs fooling fairy terns

A new tool — a 3D printer — is being used in the fight to save New Zealand’s rarest bird.

The NZ fairy tern, tara iti, is a critically endangered shore bird which only breeds in five sites in Northland and north Auckland.

A team of Department of Conservation rangers and volunteers works year-round to protect the tara iti nests, including trapping predators, create safe nesting environments and preventing disturbance near nesting sites.

Now, DOC and partners have made a breakthrough in endangered species conservation by using 3D-printed replica eggs to safeguard the nests, helping the birds have a record-breaking breeding season.

The replica eggs are used as a management tool during high-risk periods — such as storms and high tides — allowing the adult birds to continue incubating while their real eggs are temporarily held in incubators or moved to safety at Auckland Zoo.

Initially, DOC used hand-painted wooden eggs, followed by real eggs with hollow interiors filled with wax. However, these methods presented challenges as the eggs became fragile over time.

In 2023, with funding from the Endangered Species Foundation Tāngaro Tuia te Ora, DOC commissioned Shaun Lee to produce 3D replica eggs, which were then handpainted by artist and marine biologist Carina Sim-smith.

The replica eggs have undergone meticulous design considerations including shape, weight, UV resistance, size, colour and texture.

The resulting eggs are so close to the real thing, tara iti parents are oblivious when they are swapped out.

The replica eggs, and broader tara iti conservation, has led to a recordbreaking breeding season this summer, with 22 eggs laid and 14 chicks successfully hatched.