Environment – Warm welcome for little penguin families

Tiritiri Matangi is home to some hundreds of nesting kororā, little penguins. They have been living on the island for decades, perhaps much longer. 

On the mainland, they are vulnerable to attacks from dogs and sometimes to competition from humans for their preferred nesting sites. But on the island, they are relatively safe. There are plenty of available nesting sites in holes under flax bushes and other vegetation, under buildings and boardwalks, in drainage pipes, and even in wooden nest boxes (where we can easily follow their progress through the season).

The nesting season begins around July and can end as late as February, if they make two attempts. On a typical evening, just as it’s getting dark, the kororā assemble in small groups a few tens of metres offshore, where we can hear their donkey-like braying calls. 

Once they consider it sufficiently dark for a safe landing, the kororā arrive at the waters’ edge and quickly cross the beach and into the cover of the vegetation. Once ashore they head for their chosen nest location which can be anywhere from a few metres to over a kilometre inland. 

Each female lays two eggs which the parents take turns to incubate, until the eggs hatch about five weeks later. One parent will then stay with the young chicks until they are about three to five weeks old. The chicks fledge once they are seven or eight weeks’ old.

During chick rearing the parents need to find enough food for themselves and their chicks. As the kororā cannot fly, and need to return to the nest about 24 hours after leaving, they can only feed within about 20 kilometres of their nest site. They feed on small fish, crustaceans and squid.

A year ago, around early October, all of the chicks on Tiritiri Matangi Island, Motuora Island, and at other sites around the Hauraki Gulf died, probably from starvation. It’s likely that the parents couldn’t find enough food to bring back to the chicks so abandoned them. Penguins are long-lived, perhaps 15-20 years, and it works out better for them if the adults abandon their chicks so that they can survive to try again in future years. Of course, if it’s really bad then the adults will die as well.

We didn’t know whether this had happened until this June when lots of adults returned safely with their mates and reclaimed their nest boxes. This year the kororā have been much more successful with most pairs raising two big healthy chicks, many of which have already fledged. A few parents seem to be about to try for a second family.

Episodes like this provide useful information about the state of the gulf at a local level. These ups and downs have occurred over many years and no clear pattern has yet emerged. We are watching carefully, hoping that kororā have a long-term future in the gulf.