Reading — 2026 Jan–Apr Recall Set 69

One native bird in New Zealand that has managed to survive the introduction of non-native species As an island country with a fauna dominated by birds, New Zealand was once home to an owl species which is now extinct, the laughing owl, named for its distinctive cry. This bird was widespread throughout the islands when European settlers arrived in the middle of the 19th century and it remained in good numbers for some years thereafter. Where other native birds suffered from predation by the Polynesian rat, the laughing owl turned the tables and adapted its diet to include the rodent. It was also capable of catching and killing the other New Zealand owl, the morepork, and even larger birds, such as the weka. However, the laughing owl was wiped out around the beginning of the 20th century, its demise caused by specimen collectors, habitat changes, and non-native predators including cats and stoats. Surprisingly, it is the smaller owl, the morepork, that has managed to survive until this day. Speckled dark brown, with yellow eyes and long tails, they are around 29 centimetres long from head to tail and 175 grams in weight. Moreporks have fringes on the edge of their feathers, so they can fly almost silently and not alert potential prey. They have acute hearing and their large eyes are very sensitive to light. Moreporks nest in tree hollows, in clumps of plants, or in cavities among rocks and roots. In the wild, moreporks usually start nesting in October, although two specimens have been recorded nesting in mid-winter, possibly stimulated by an ample food supply. The female lays up to three white eggs, which she incubates for 20 to 30 days. During this time, she rarely hunts, and the male brings food to her. Once the chicks hatch, she stays mainly on the nest until the young owls are fully feathered. When hatched, chicks are covered in light grey down and have their eyes closed. The eyes do not open until the eighth day after hatching. They can fly at around 35 days. By day, moreporks sleep in roosts. By night, they hunt a variety of animals – mainly large invertebrates including scarab and huhu beetles, moths, caterpillars and spiders. They also take small birds and mice. They can find suitable food in pine forest as well as native forest. A morepork uses its sharp talons to catch or stun its prey, which it then carries away in its bill. Moreporks are clever hunters, and birds such as robins, grey warblers and fantails can end up as their prey. In the day, these small birds sometimes mob drowsy moreporks and chase them away from their roosts; they force the sleepy predators to search for a more peaceful spot. Moreporks have proved to be ungracious hosts. Scientists trying to establish a population of plovers on Motuora Island in New Zealand’s Hauraki Gulf were mystified as to why only two birds survived out of the 75 placed there. The culprits turned out to be five pairs of moreporks that ate or chased away the new arrivals. Although moreporks are still considered to be relatively common, it is likely that numbers are in gradual decline due to predation and loss of habitat. As the female is a hole-nester, she is vulnerable to predators such as stoats and possums during the breeding season, and eggs and chicks will also be at risk from rats. The use of pesticides is another possible threat to the owls, though not a direct one. As moreporks are at the top of the food chain, they could be affected by an accumulative poison by consuming prey that has ingested poison. The New Zealand Department of Conservation is taking steps to ensure the preservation of New Zealand’s only native owl. The department is involved in measuring the population of moreporks and has put transmitters on a number of birds to determine survival and mortality. As well as being New Zealand’s only native owl, the morepork has symbolic and spiritual importance, so in monitoring the birds it is hoped that the morepork will continue to survive and thrive. At dusk, the melancholy sound of the morepork can be heard in forests and parks as it calls to other moreporks and claims territory. Its Māori name (ruru) echoes its two-part cry. In the tradition of the Māori people of New Zealand, the morepork, or ruru, was often seen as a careful guardian. A number of sayings referred to the bird’s alertness. As a bird of the night, it was associated with the spirit world. Moreporks were believed to act as messengers to the gods in the heavens, flying along spiritual paths in the sky. They were the mediums used to communicate with the gods. The occasional high, piercing call of the morepork signified bad news, but the lower-pitched and more common “ruru” call heralded good news.

A little over a century ago, men of the ilk of Scott, Shackleton and Mawson battled against Antarctica's blizzards, cold and deprivation. In the name of Empire and in an age of heroic deeds they created an image of Antarctica that was to last well into the 20th century – an image of remoteness, hardship, bleakness and isolation that was the province of only the most courageous of men. The image was one of a place removed from everyday reality, of a place with no apparent value to anyone. As we enter the 21st century, our perception of Antarctica has changed. Although physically Antarctica is no closer and probably no warmer, and to spend time there still demands a dedication not seen in ordinary life, the continent and its surrounding ocean are increasingly seen to be an integral part of Planet Earth, and a key component in the Earth System. Is this because the world seems a little smaller these days, shrunk by TV and tourism, or is it because Antarctica really does occupy a central spot on Earth's mantle? Scientific research during the past half century has revealed – and continues to reveal – that Antarctica's great mass and low temperature exert a major influence on climate and ocean circulation, factors which influence the lives of millions of people all over the globe. Antarctica was not always cold. The slow break-up of the super-continent Gondwana with the northward movements of Africa, South America, India and Australia eventually created enough space around Antarctica for the development of an Antarctic Circumpolar Current (ACC), that flowed from west to east under the influence of the prevailing westerly winds. Antarctica cooled, its vegetation perished, glaciation began and the continent took on its present-day appearance. Today the ice that overlies the bedrock is up to 4km thick, and surface temperatures as low as -89.2°C have been recorded. The icy blast that howls over the ice cap and out to sea – the so-called katabatic wind – can reach 300 km/hr, creating fearsome wind-chill effects. Out of this extreme environment come some powerful forces that reverberate around the world. The Earth's rotation, coupled to the generation of cells of low pressure off the Antarctic coast, would allow astronauts a view of Antarctica that is as beautiful as it is awesome. Spinning away to the northeast, the cells grow and deepen, whipping up the Southern Ocean into the mountainous seas so respected by mariners. Recent work is showing that the temperature of the ocean may be a better predictor of rainfall in Australia than is the pressure difference between Darwin and Tahiti – the Southern Oscillation Index. By receiving more accurate predictions, graziers in northern Queensland are able to avoid overstocking in years when rainfall will be poor. Not only does this limit their losses but it prevents serious pasture degradation that may take decades to repair. CSIRO is developing this as a prototype forecasting system, but we can confidently predict that as we know more about the Antarctic and Southern Ocean we will be able to enhance and extend our predictive ability. The ocean's surface temperature results from the interplay between deep-water temperature, air temperature and ice. Each winter between 4 and 19 million square km of sea ice form, locking up huge quantities of heat close to the continent. Only now can we start to unravel the influence of sea ice on the weather that is experienced in southern Australia. But in another way the extent of sea ice extends its influence far beyond Antarctica. Antarctic krill – the small shrimp-like crustaceans that are the staple diet for baleen whales, penguins, some seals, flighted sea birds and many fish – breed well in years when sea ice is extensive and poorly when it is not. Many species of baleen whales and flighted sea birds migrate between the hemispheres and when the krill are less abundant they do not thrive. The circulatory system of the world's oceans is like a huge conveyor belt, moving water and dissolved minerals and nutrients from one hemisphere to the other, and from the ocean's abyssal depths to the surface. The ACC is the longest current in the world, and has the largest flow. Through it, the deep flows of the Atlantic, Indian and Pacific Oceans are joined to form part of a single global thermohaline circulation. During winter, the howling katabatics sometimes scour the ice off patches of the sea's surface leaving large ice-locked lagoons, or 'polynyas'. Recent research has shown that as fresh sea ice forms, it is continuously stripped away by the wind and may be blown up to 90km in a single day. Since only fresh water freezes into ice, the water that remains becomes increasingly salty and dense, sinking until it spills over the continental shelf. Cold water carries more oxygen than warm water, so when it rises, well into the northern hemisphere, it reoxygenates and revitalises the ocean. The state of the northern oceans, and their biological productivity, owe much to what happens in the Antarctic.

A In 1877, Giovanni Schiaparelli, an Italian astronomer, made drawings and maps of the Martian surface that suggested strange features. The images from telescopes at that time were not as sharp as today’s. Schiaparelli said he could see a network of lines, or canali. In 1894, an American astronomer, Percival Lowell, made a series of observations of Mars from his own observatory at Flagstaff, Arizona, U.S.A. Lowell was convinced a great network of canals had been dug to irrigate crops for the Martian race. He suggested that each canal had fertile vegetation on either side, making them noticeable from Earth. Drawings and globes he made show a network of canals and oases all over the planet. B The idea that there was intelligent life on Mars gained strength in the late 19th century. In 1898, H. G. Wells wrote the science-fiction classic The War of the Worlds about an invading force of Martians who try to conquer Earth. They use highly advanced technology (advanced for 1898) to crush human resistance. In 1917, Edgar Rice Burroughs wrote the first in a series of 11 novels about Mars. Strange beings and rampaging Martian monsters gripped the public’s imagination. A radio broadcast by Orson Welles on Halloween night in 1938 of The War of the Worlds caused widespread panic across America; people ran into the streets in their pyjamas—millions believed the dramatic reports of a Martian invasion. C Probes are very important to our understanding of other planets. Much of our recent knowledge comes from these robotic missions into space. The first images sent back from Mars came from Mariner 4 in July 1965. They showed a cratered and barren landscape, more like the surface of our Moon than Earth. In 1969, Mariners 6 and 7 were launched and took 200 photographs of Mars’s southern hemisphere and pole on fly-by missions, but these revealed little more information. In 1971, Mariner 9 became the first spacecraft to orbit the planet, circling every 12 hours. In 1975, the U.S.A. sent two Viking probes, each with an orbiter and a lander. The landers had sampler arms to scoop up Martian rocks and carried out experiments to try to find signs of life. Although no life was found, they sent back the first colour pictures of the planet’s surface and atmosphere from pivoting cameras. D A Martian meteorite found on Earth raised fresh doubts about the above analysis. Meteorite ALH 84001 was discovered in December 1984 in Antarctica by members of the ANSMET project. The sample was ejected from Mars about 17 million years ago and spent 11,000 years in, or on, Antarctic ice sheets. NASA’s compositional analysis revealed a kind of magnetite that on Earth is only found in association with certain micro-organisms. Some structures resemble the mineralised casts of terrestrial bacteria and their appendages, fibrils or by-products occurring in the rims of carbonate globules and pre-terrestrial aqueous-alteration regions. The size and shape of the objects are consistent with Earthly fossilised nanobacteria, but the very existence of nanobacteria is still controversial. E In 1965, the Mariner 4 probe discovered that Mars had no global magnetic field to protect the planet from potentially life-threatening cosmic and solar radiation; observations made in the late 1990s by Mars Global Surveyor confirmed this discovery. Scientists speculate that the lack of magnetic shielding helped the solar wind blow away much of Mars’s atmosphere over several billion years. After mapping cosmic-radiation levels at various depths on Mars, researchers concluded that any life within the first several metres of the planet’s surface would be killed by lethal doses of radiation. In 2007 it was calculated that DNA and RNA damage would limit life on Mars to depths greater than 7.5 metres below the surface. Therefore, the best places to look for life may be subsurface environments that have not yet been studied. The disappearance of the magnetic field may have played a significant role in Martian climate change. According to scientists’ evaluation, Mars’s climate gradually transitioned from warm and wet to cold and dry after the magnetic field vanished. F NASA’s recent missions have focused on another question: whether Mars had lakes or oceans of liquid water on its surface in the ancient past. Scientists have found hematite, a mineral that forms only in the presence of water. Thus, the 2004 Mars Exploration Rovers were designed not to look for present or past life, but for evidence of ancient liquid water. Because of Mars’s current low atmospheric pressure and temperature, liquid water cannot persist at the surface except, briefly, at the lowest shaded elevations. In March 2004, NASA announced that its rover Opportunity had discovered evidence that Mars was once a wet planet. This raised hopes that evidence of past life might still be found. Later the Mars Express orbiter detected huge reserves of water-ice at Mars’s south pole in January 2004. G Researchers from the Center for Astrobiology (Spain) and the Catholic University of the North in Chile have found an oasis of micro-organisms two metres below the surface of the Atacama Desert. SOLID, a life-detection instrument, could be used in environments similar to Martian sub-soil. “We have named it a microbial oasis because we found micro-organisms developing in a habitat rich in rock salt and other highly hygroscopic compounds that absorb water,” explained Víctor Parro of the Center for Astrobiology. “If similar microbes, or their remains, exist on Mars under comparable conditions, we could detect them with instruments like SOLID,” Parro added. H Even more intriguing is an alternative scenario proposed by the Spanish scientists. If samples on Mars were found to use DNA—as Earthly life does—it would be extremely unlikely that such a specialised, complex molecule could have evolved independently on two planets. This would indicate a common origin for Martian and Earth life. Life based on DNA might have appeared first on Mars and then spread to Earth, where it evolved into the myriad plants and creatures alive today. If that proved true, we would face a startling conclusion: we are all Martians. If not, we must continue the search for other signs of life.