3 minute read
Notices
THIS IS YOUR NEW HOME: Morag Fordham welcomes Te Rae, a Taranaki bird bred at Mt Bruce, to Tiritiri. Photo / Simon Fordham
Mount Bruce in 2001 and spent the intervening years in captivity there and at Otorohanga Kiwi House and Native Bird Park. During his first few months on Tiritiri he went around the whole Island singing what, to human ears, sounded like a broad and rich repertoire of kōkako song. After that he gradually reduced his range of calls and started using the local dialect and holding a territory, but he failed to attract any female for more than a few weeks. He was eventually pushed out of his territory, and it was not until 2015 that he settled into a new one with two-year-old Tiara.
Advertisement
On 17 October 2010 three more birds from the Waipapa region, Tawa, Slingshot and Rimu (all males), were released on Tiritiri. They remained quiet and fairly elusive for their first three years, but by 2014 Slingshot and Tawa were holding a territory and singing together. Like Crown and Pureora they sang mostly in the Tiritiri dialect but retained some calls from their original Waipapa song. By late 2017 Tawa had disappeared, Slingshot had paired up with Melodie, and had lost all trace of his original song.
The third male, Rimu, was hardly ever seen or heard during his first six years on the Island. He eventually set up a territory, attracted a mate and was frequently heard singing the Tiritiri dialect.
What, if anything, can we learn from all this about whether dialect affects the ability of incoming kōkako to integrate into a resident population? We can certainly draw no general conclusions; our sample is far too small. Only 11 of our kōkako have arrived on Tiritiri to find a local dialect already established. And there are too many variables within this small sample.
The incoming birds have included single males, single females and pairs, captivebred birds and wild-caught birds, young birds, mature birds and birds of unknown age. The circumstances present on the Island at the time of their arrival, such as whether there were desirable territories and potential partners available, also varied.
The following comments draw comparisons between some of the behaviours and experiences of the arriving birds, but we are not suggesting that they are more widely applicable.
The two single Taranaki females demonstrated that partnerships could be formed between birds who had grown up learning different dialects. They also showed that the local dialect could be adopted within two or three months.
We also know of two females translocated from Tiritiri to the Hunua Ranges in May 2007 who quickly adopted the local dialect and bred during the following season. In general (but not exclusively), females tend to join males in established territories, whereas males set up territories first and then attract females.
Most of the males who arrived without partners, plus Waipapa who, though he arrived with Māwhero, did not hold a territory with her, were mostly silent for the first four to nine years of their residence. But we have no reason to assume that they wouldn’t have learned the local song as quickly as the single females did. It seems likely that the difficulty of claiming territories in an area with an established population delayed their integration more than dialect differences would have done.
It is unsurprising that birds who arrived with the same dialect and who stayed together (as Crown and Pureora did), or formed an association later (as Tawa and Slingshot did), should retain some elements of their original song for longer than those who remained alone or associated only with locals. We can speculate that Waipapa and Māwhero might have done this had they held a territory.
Poutama, who had spent seven years in captivity before arriving on the Island, was the only male who started singing shortly after his arrival and who sang his own original repertoire before gradually adopting the local song. We can only guess how a captive bird might have acquired such a repertoire.*
One thing we can say for certain. If we are ever fortunate enough to receive more kōkako onto the Island, we shall be watching and listening to them more closely than ever.
