Hopes high for Pirongia kōkako population

Volunteers were banding and monitoring the kōkako chicks. Photo / Carisse Enderwick, DoC

Although this year's nesting season has come to an end, ecologists are still waiting for an additional 20 or more kōkako fledglings in Pirongia Forest Park.

The Pirongia Te Aroaro O Kahu Restoration Society (PRS) has almost completed its annual kōkako nest monitoring and has observed nine pairs since the start of the season in September. Each pair is incubating and rearing at least one clutch of chicks and, in the case of one pair, three clutches.

Kōkako eggs and chicks are extremely vulnerable to pests like ship rats, possums and mustelids. In the 1990s the birds completely disappeared from the maunga Pirongia, which is why pest management is crucial for the survival of the local bird population.

The PRS is supported by more than 100 volunteers, trappers, ecologists, DoC and iwi. Chairwoman of the PRS, Clare St Pierre, says: "We set 20 rat traps and one to two possum traps around the base of the nesting tree and check them every four days. Rats and possums have already been caught."

Soon, the kōkako chicks will start fledging and spread their wings to make their first leap off the branch. Photo / Carisse Enderwick, DoC

Due to the extensive pest management, PRS was able to move 20 birds back in the Pirongia Forest Park in 2017, and a further 14 in 2018.

Kōkako ecologists Dave Bryden and Amanda Rogers are working with the PRS and headed into the predator control area to locate pairs in October last year - with the help of song recordings.

Rogers says: "Recordings of the birds are played in the forest at 200m intervals. If the birds have paired up, they'll be defending a territory and will investigate the song."

Once the ecologists identified a pair, they watch closely for nesting behaviours: birds carrying sticks, moss and fern fronds; and beak-to-beak courtship feeding. A female might also disappear into the tree for a long period of time.

Rogers says: "Within 60 minutes you should be able to see parents feed the chicks. If the female is incubating, the male will usually feed her every 20 – 30 minutes. You can gauge the age of the chicks by how frequently they need to be fed, and whether they need to be brooded for warmth or if they have their own feathers.

"The volunteers are looking forward to fledging day, when a young bird wanders off the nest and takes its first daring leap off the branch."

Kōkako Pavarotti has not found a partner yet. Photo / Amanda Rogers

But not all birds are lucky in love and producing offspring. St Pierre says: "In Pureora Forest Park a majestic male kōkako was caught for translocation to Pirongia in 2018. He weighed 283g [a small adult is 190g] so he's really big."

The big male bird, named Pavarotti, has been seen with three females and has attempted a duet with two.

"Unfortunately, Pavarotti hasn't yet found 'the one'. We're hoping he finds true love next season."

Department of Conservation (DoC) biodiversity ranger Cara Hansen works closely with the PRS, providing technical advice and support.

"The PRS is doing fantastic work including 1300 hectares of annual pest control, which DoC supplements with landscape-scale pest control across the entire 12,500 hectares of forest. It's making a difference, and the birds are evidence of that."

The PRS welcomes new members to help with any number of its projects, including kōkako nest monitoring. More information can be found here.