Academic Reading — Test 140

Reading passage

The kakapo is a large, flightless, nocturnal parrot found only in New Zealand. Once common across the country's forests, it was driven to the edge of extinction after the arrival of human settlers and the predators they brought with them, including rats, cats and stoats. By the mid-1990s, fewer than fifty birds remained, and conservationists feared that the species would vanish altogether. In response, the New Zealand government established a dedicated recovery programme, moving every surviving kakapo to a small number of predator-free offshore islands where the birds could breed without being hunted. Because so few individuals were left, managers concluded that the population could not be treated as an anonymous mass; instead, each bird would have to be known and managed as an individual. This decision gave rise to one of the most intensive monitoring efforts ever applied to a wild animal. Every living kakapo is given a name and a unique identity, and a detailed record is kept of its health, weight, location and breeding history. Central to this approach is genetic tracking. A small blood or feather sample is taken from each bird, and its DNA is analysed to build a genetic profile. These profiles are stored in a central database that, in effect, functions as a family tree for the entire species. Because the founding population was so small, almost every kakapo alive today is related to the others, and without careful records it would be easy for close relatives to breed together. The danger of such inbreeding is well understood. When closely related animals reproduce, harmful genetic variants are more likely to appear in their offspring, which can reduce fertility, lower the survival of chicks and leave the population less able to adapt to disease. By comparing the genetic profiles of individuals, scientists can estimate how closely any two birds are related before they pair. This information allows managers to encourage matings that maintain as much genetic variation as possible. In some cases, eggs or chicks are moved between islands so that the offspring of under-represented birds are given the best possible chance of surviving and, eventually, of breeding themselves. Genetic data also guide decisions during the breeding season itself, which on the islands is tied to the irregular fruiting of the native rimu tree. Kakapo tend to breed only in years when this tree produces a heavy crop of fruit, so such seasons are precious and cannot be wasted. Staff monitor nests closely, and when a female lays eggs, the team can use the genetic database to judge whether her contribution is valuable to the wider population. Some males, in particular, are descended from a single long-isolated bird that carries genetic material absent from the rest of the population, and ensuring that these distinctive lines are passed on is treated as a priority. Artificial insemination has occasionally been used to help such valued males father chicks when natural mating has not succeeded. The programme has not been without setbacks. Disease outbreaks, infertile eggs and the deaths of individual birds have all threatened progress, and the slow pace of kakapo reproduction means that recovery is measured in decades rather than years. Even so, the combination of individual identification, intensive nest management and genetic record-keeping has steadily lifted numbers. From the low point of the 1990s, the population has more than tripled, and birds have been returned to additional islands to spread the risk that a single catastrophe might wipe them out. Researchers have even sequenced the complete genome of every living kakapo, giving them an unusually precise picture of the genetic health of the whole species. The kakapo programme is now widely cited as a model for the conservation of other critically endangered species. Its central lesson is that, when a population becomes very small, treating animals as interchangeable units is no longer enough. Knowing exactly who each individual is, how it is related to the rest, and what unique genetic inheritance it carries allows conservationists to make choices that a less detailed approach could never support. For the kakapo, this painstaking, bird-by-bird attention may make the difference between slow recovery and final disappearance.