1998

After an interval of five years breeding occurred this year on Codfish Island. The close-order management strategy and techniques devised following the previous (unsuccessful) breeding event - involving support of breeding females through provision of supplementary foods, effective protection of nests from rats, and intensive monitoring of each nest - proved not only practicable, but crucial to successful reproduction. Three chicks were raised - the greatest number to survive since 1981. This, together with the fact that no adult mortality is known to have occurred for almost four years means that the remnant population has increased slightly for the first time since management began! During the 1997 winter five birds were moved between islands and one "new" female found.

---

Little Barrier Island: Twelve birds (9 male and 3 female) are on Little Barrier Island (LBI). With the exception of two males raised on the island in 1991, all have free-ranged there since being transferred from Stewart Island in 1982. Two of the females and four of the males are supplementary-fed. Supplementary food consumption is declining with the onset of summer. As in previous years attempts to train the remaining female ("Jean") to accept supplementary foods were unsuccessful.

Some bowl (=court) activity has been seen in recent weeks and six bowl systems are currently active, but booming has not yet begun. Breeding last occurred on LBI in 1995 (two infertile clutches).

---

Maud Island: Seven birds (4 male and 3 female) are currently free-ranging on Maud Island. All are supplementary-fed. As on LBI the level of supplementary food consumption is currently declining with the onset of summer.

Some bowl activity has been apparent since September and at least one male has been booming since 19 November. To date, breeding is not known to have occurred on Maud.

---

Whenua Hou/Codfish Island: Thirty one birds (17 male - including 3 juveniles from the 1997 breeding season - and 14 female) are on Codfish Island.

The three juveniles raised this season are doing well. "Manu" and "Tiwai", now 8 months old, are approx. 2.4 and 2.2 kg respectively, which is around a kilogram heavier than their mothers. Both are still within their natal home-ranges and associating with their mothers. The partially hand-raised juvenile "Sirocco" has recently maintained a weight of 1.7 - 1.8 kg. His respiratory condition as a nestling has left a legacy of slight weaziness.

With the exception of one adult male ("Ken"), recovering from a transmitter harness injury, all kakapo on Codfish are free-ranging. Eleven of the 14 females and 9 of the 17 males are supplementary fed.

Six bowl systems have shown signs of activity during the last few weeks, but booming has not yet been heard.

---

Holding island: Four males suspected of being infertile or of low fertility are being held on an island off southern Stewart Island.

---

For these reasons too the captive female "Hoki" from Maud Island was in July 1997 released to free-range on Codfish Island. Both Maggie and Hoki were held in pens at their release sites for ~2 weeks prior to release (ie. soft release). Once released they remained nearby and continued to feed from their allotted feeding stations. However, Bella was held on site for one week only before being released. She initially ranged widely and has ceased taking supplemental foods.

A previously unknown female was found in the south of Stewart Island in June and transferred to Codfish Island by members of an expedition organised and led by Grant Harper. The possibility of further individuals persisting in the vast scrub lands of southern Stewart Island cannot be discounted - making further searches there a priority.

Two Codfish Island males ("Boss" and "Ben"), believed to have mated with females that produced infertile clutches earlier this year and thus whose fertility is in question, were removed to a holding island in September.

Two of the four surviving nestlings were left with their (supplementary-fed) mothers. The other two were removed during the nestling stage for veterinary care and hand-raising when ailments were detected. All four survived to fledging-age (~11 weeks) when one of the partially hand-raised chicks ("Gromette") died. The necropsy report by Massey University veterinarians concluded that the cause of death stemmed from prolonged use of antibiotics (in particular Batryl). Without such intervention however, death would have resulted anyway, for Gromette was severely stunted as a result of chilling in the egg/early nestling stages, as well as under-feeding during the first two weeks of life.

As occurred in the 1992 season, the rimu mast crop in 1997 failed - fruit did not ripen and aborted - and as in 1992 it was apparent that non-supplementary-fed females were stressed for food to such an extent they were unable to incubate effectively or to raise young. Non-supplementary fed females spent more than twice as much time off the nest foraging each night than supplementary-fed females. Thus, it was necessary to take Gromette from her (non-supplementary-fed) mother at 12 days since she was seriously underweight. She was however stunted and died at fledging age (~ 11 weeks).

At ~23 days "Sirocco" developed respiratory problems during a prolonged cold, wet spell and began to lose weight. He responded to treatment and was successfully hand-raised at Burwood Bush. Sirocco was returned to Codfish Island in early July and was released to free-range there in late November. All three young raised in 1997 were male - the two chicks that died were female!.

Unless the cue(s) which trigger breeding in kakapo can be identified and simulated it is unlikely that breeding will occur there again until the next rimu masting event. Masting normally occurs at up to five yearly intervals, however there are indications that rimu masting may occur again in 1998! Graeme Elliott and Ros Cole have recently assessed rimu fruit development on Codfish and have found it to be similar to that of this time last year.

The year-round ad lib feeding regime which had been in place since 1993 was discontinued in 1997. It has been replaced by a regime intended to more closely simulate natural cycles of food availability through ad lib feeding during autumn and early winter; a reduction in the range and volume of foods fed during winter and early spring (so as to encourage foraging on natural foods as well as greater mobilisation of body fat reserves) and provision of a flush of food from late spring.

Following discussion with animal nutritionists from Massey University and Profile Foods (Auckland) it is proposed during the coming year to phase-out the existing range of supplementary-foods and replace them with a pelleted diet formulated specifically for kakapo. A pelleted diet will make it possible to manipulate nutrient, vitamin, mineral and hormonal intake, while further reducing organophosphate levels.

Little Barrier and Codfish Island accommodation upgrades have now been completed.

At the request of Birds Australia (formerly Royal Australasian Ornithologist's Union) Don Merton recently compiled the kakapo passage for the latest volume of the Handbook of Australian, New Zealand and Antarctic Birds. This is the most comprehensive and up-to-date account of kakapo biology.

Nadine Parker joined the National Kakapo Team in October on a two year contract to research aspects of kakapo diet through analysis of cuticles from droppings.

Daryl Eason has been seconded for two months to the Echo parakeet recovery programme in Mauritius.

UPDATE ARCHIVE
June 1999  |  January 1999  |  1998  |  1997