Kakapo Know What's Best!

Jenny and Malcolm Lawrence have come to the rescue of the Department of Conservation National Kakapo Team. Apparently Kakapo like walnuts and they may help the Kakapo breed successfully. With the help of other growers, Jenny has sent of several shipments of green walnuts. The following is an extract from the Kakapo Update (March 2005), published by the Team.

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For many years the kakapo team has been trying to establish exactly what initiates breeding in certain years, and a great deal of research time and effort has been devoted to this elusive goal. If we could identify the trigger we might be able to simulate it - and so induce breeding at more frequent intervals: This could speed the rate of recovery dramatically! On Whenua Hou, kakapo feed on the green, developing rimu fruit, and breed in synchrony with the ripening of heavy ("mast") crops that occur every 3-5 years. Clearly, the birds are able to anticipate these mast crops many months before they happen, and we suspect that hormones contained within the green developing fruit may be the key.

Rimu fruit developing on Whenua Hou, Te Kakahu and Anchor Islands was sampled in March 2004, and that on Whenua Hou was assessed again in October 2004 and February 2005. Individual rimu trees were found to have a reasonable amount of fruit, but overall the crop was below the lowest level that is known to have triggered breeding on Whenua Hou in the past. Thus, it seemed unlikely that breeding would occur in early 2005 unless it could be triggered artificially - through supplementary feeding perhaps.

It is not practical to pick tiny green rimu fruit in sufficient quantity for storage and subsequent supplementary feeding since the fruit is produced high in the forest canopy and each weighs ~150th of a gram! We assume that plant hormones present in green rimu fruit, are also present in some other developing fruits, & it seems likely that exotic pines may serve a similar role in this regard as native conifers. For example, Pinus radiata foliage, stems, pollen cones & small green cones are readily eaten by some kakapo, & in 1998 "Flossie" & "Richard Henry" kakapo bred successfully on Maud Island on this unlikely diet! Walnuts are another favourite food of kakapo, and one of the few that might be fed as a supplement while fresh & in a partially developed green state during the weeks leading up to a potential breeding season.

Having exhausted other options in previous years (eg pulse feeding, ad lib feeding, manipulation of nutrient levels, feeding freeze-dried & frozen ripe podocarp fruit), we opted this season to feed them small green walnuts & pine conelets. Screening green podocarp fruit for unspecified hormones would be expensive since it is likely a large number of hormones is present - and once identified, we'd then need to trial each at the appropriate season on the few kakapo - and that could take years! Feeding green pine conelets to one group of birds and green walnuts to another just might short-cut all of this!

We therefore ad lib fed green walnuts to half of the adult females and some genetically under-represented males, and green pine conelets to the remaining females and other males on Whenua Hou from early November 2004 to mid February 2005 in an attempt to stimulate breeding. We are, as yet, uncertain what sparked breeding this year, but if in fact it was the green supplementary foods, then this will represent an important break-through!