Our Changing World for Thursday 23 April 2009
Kakapo Daily Management
In the final episode in our kakapo series we find out about the daily routine of some of the many people involved in kakapo management on Whenua Hou - Codfish Island. At the height of this year's breeding season there were up to 34 people on the island, including kakapo rangers and other members of the National Kakapo team, and many volunteers involved in both the supplementary feeding programme and in 'nest minding' duties.
The focus has now moved away from the island as 26 chicks are being hand-reared at a special facility in Invercargill - hand rearing became necessary when the rimu crop failed to ripen, and females were finding it hard to feed chicks,. The oldest of the 7 chicks still being reared by kakapo mums on Codfish Island is now more than 2 months old. If all of these chicks survive (which is not yet guaranteed) they will bring the kakapo population to 125 birds, up from 91 at the beginning of the breeding season.
Adelie Penguin Genetics
Subfossil bones of Adelie penguins, found underneath existing and abandoned nesting colonies in Antarctica, are so well preserved that they still contain intact DNA. A comparison of the ancient DNA with that of living birds showed that the rate of evolution in Adelies is up to seven times higher than previous estimates that were based on comparisons between fossils of closely related species. Further studies showed that the high evolutionary rate is caused by a high mutation rate, but that most of these mutations remain neutral, i.e. they don't result in any changes in the birds' physical appearance. Craig Miller, an evolutionary biologist at the University of Auckland and the Allan Wilson Centre for Molecular Ecology and Evolution says this supports the idea that genotype changes can be uncoupled from phenotype changes.
Moa specialist Richard Holdaway studied North Canterbury moa fossils, using the latest in biological technologies, to find out whether moa populations that existed before human settlement were stable or declining.
In the late 1930s, a deposit of moa bones was found at Pyramid Valley swamp in North Canterbury. Sixty five years later, an equally impressive collection was discovered nearby, beneath Bell Hill Vineyard. These two swamps trapped birds of all ages, and included at least four species of moa from a period going back 4000 years.
Holdaway's team, including Morten Allentoft, who is pictured on the left drilling a moa bone for samples, used radiocarbon dating to age the bones and ancient DNA analysis to identify the species of moa, their sex, estimates of population sizes, and family relationships. Carbon and nitrogen isotope data were used to study the diet and habitat of each moa species.
Royal Albatrosses on Campbell Island
There are two species of royal albatross; southern royals breed mainly on Campbell Island, while northern royal albatrosses are slightly smaller and breed at the Chatham Islands and at Taiaroa Head near Dunedin. Department of Conservation scientist Peter Moore has been studying and surveying southern royal albatrosses on Campbell Island for the last 20 years. From the 1940s on, about 35,000 albatrosses were fitted with leg bands, and this summer was the final year in a five-year effort to remove these bands from most birds. Peter and his team have established a 200-hectare study area, within which birds have been re-banded and fitted with transponders.
Royal albatrosses displaying on Campbell Island (image: Alison Ballance).