S C I E N C E

LOOK TO THE ANT, THOU SLUGGARD

Sun, 21 Apr 2013 12:09:19 +0800

The organisation of ants may offer the modern workplace a few lessons

Hands up, those of you who daydreamed through a meeting this week.

Few would deny that memos, meetings and over-management plague the modern workplace, often stopping us from getting things done. Frequent interruptions have fractured our ‘workday’ into a series of ‘work moments.’

The solution may lie with the ants, or more specifically, with ant behaviour. Unlike human hierarchies, ants act collectively – building colonies, foraging, waging war – without directives or leaders. (Even the ‘queen’, despite her officious name, offers no real leadership, but simply fulfills her programmed role of churning out offspring.)

Ants, it turns out, are pretty much on their own. And yet without leaders or directives, these tiny insects are able to achieve all they do through collective decision-making - based on subtle interactions with each other and with the local environment. Clearly this goes against the grain of human hierarchies found in offices and corporations.

But could these same ideas be applied to human contexts? As it is, such ‘ant algorithms’ have already been applied successfully in areas like robotics and computer science. More tellingly, a recent study from Wayne State University showed that modeling management structure on the eusocial insects (ants, bees, termites) was able to foster innovation among staff and raised overall efficiency by 17%.

Now before anyone starts chanting ‘we are the Borg, you will be assimilated!’ it should be noted that such structures are not about stifling individuality, but rather reducing micromanagement and freeing up time.

This idea already has a precedent in the workplace. Game designer ‘Valve’, for example, has received plaudits for its ‘flat’ management style where “nobody reports to anybody else” and employees “have the power to greenlight projects.”

So the next time you’re hovering over your employees or about to call that power meeting, you might want to ask yourself whether it’s really constructive. Your time might be better spent on studying how ants work.

As the old proverb goes: ‘Look to the ant, thou sluggard. Consider her ways and be wise.”

A modified version of this article was published in THE PEAK magazine.

THE SECRETS OF SCHOOLING FISHES

Sun, 5 Dec 2010 06:30:52 +0800

Group living offers some distinct survival benefits.

WE’VE all seen them before, from a summer wharf or a holiday snorkel off Grand Caymen -- aggregates of swimming fishes, sometimes colourful and sometimes not, moving together in one startlingly unified mass. Schooling fishes have been observed and pondered over by humans for as long as there have been humans standing on shorelines to ponder. Like the old fisherman's joke about the herring being smarter than the rockfish (“it’s a matter of schooling”), this phenomenon of massing fishes has entered our popular lore. But while our familiarity with such behaviour is longstanding, our explanations of the same are relatively recent -- and still incomplete.

Speculation on the causes and significance of schooling is largely a product of the last half century, beginning with Albert Parr's landmark studies of chub mackerel (Scombrus colias) in the 1920s. Parr was the first to formally define a school of fish. He distinguished schools from chance or temporary aggregations, calling them "the type of fish-'herd' which has an apparently permanent character and is an habitual spatial relationship between individuals." (Parr, 1927). Since then, new technologies (SCUBA, television, sonar, and submersibles) have further exposed the underwater world, while the study of animal behaviour (pioneered by Tinbergen and Lorenz) has emerged as a disciplined science. The evidence, collected in myriad forms from numerous venues, has revealed some of the answers to this mystery of mass behaviour.

Schooling is one of many gregarious social systems occurring among the phyla of the animal kingdom. The great ungulate herds of Africa, flocks of birds in migration, swarms of honeybees, and shoals of squid are all different forms of group living. For fishes, schooling is a significant but not the dominant mode of sociality. Shaw (1978) estimates that 50% of fish species school as juveniles while 25% remain as lifelong schoolers. Schools of fish are found in both freshwater and marine systems and across an ecologically diverse range of species -- from planktivores to predators, from the evolutionarily "primitive" (such as herring) to the evolutionarily "advanced" (like mackerel and tuna).

So why do fish school? Ethologists (those scientists who study the behaviour of animals) view behaviour as a product of evolution, just like physiology or colour. Behaviour patterns are like genetic programs which have gained prominence in a species over time and through natural selection. In this view, schooling as a behavioural strategy must produce a tangible benefit to the fishes involved or it would not exist. Group living must, in certain circumstances, offer advantages which are unavailable to non-schooling fishes. Indeed, the current literature points to three major benefits of schooling behaviour, along with a variety of less-documented possibilities.

Evading hungry predators is one benefit of massing in a school.

EVADING PREDATORS

Defense against predators is the most frequently cited advantage of schooling. Several studies (Theodrakis 1989, Poulin & Fitzgerald 1989) have shown that fish will school more readily and more cohesively when exposed to predators. This response may be visual (for example, spotting a predator), or it may be biochemical. Heczcko and Seghers (1981) found that the presence of "Schreckstoff" (an alarm pheromone released by wounded fish) directly increased the intensity of schooling behaviour in common shiners (Notropis cornutus ).

The old platitude about there being "safety in numbers" applies to fish schools in several ways. First, there is the so called "early warning effect" -- basically the idea that many pairs of eyes can detect a predator more efficiently than one. This multiplied vigilance has long been observed among social birds and mammals (Hoogland 1979) and has been similarly documented in schools of fish. One study of glowlight tetras (Hemigrammus erythrozonus) demonstrated that they detect predators earlier and at greater ranges as their school size increases (Godin et al 1988).

Another advantage of large groups derives from the mathematics of demography, also known as the "dilution effect." As group size increases, the probability of any one fish falling victim to attack declines. Seghers (1981) outlines this ratio as being "approximately 1/N where N is the school size." Just like a Lotto 649, more participants mean a lower chance of "winning", although in this case the grand prize is patently undesirable. As long as predators remain less populous than prey and the attack rate is not excited by the existence of a school, this inverse relationship between school size and per capita risk is a tangible benefit of fish schools.

Large numbers of homogeneous prey also induce a "confusion effect" in predators. Apparently, a mass of identical, moving images is visually distracting, making it difficult for a predator to focus on any one individual. The predator hesitates and is less often successful in its attacks (Landeau & Terborgh 1986). Parrish (1989) found that Atlantic silversides (Menidia menidia) isolated from their school were 50 times as likely to be attacked by black seabass (Centropristis striata) as those remaining in the group.

Similarly, conspicuous individuals are more easily captured by predators. Landeau & Terborgh (1986) observed that minnows, when dyed blue, were singled out of a school by predatory largemouth bass (Micropterus salmoides). Similarly, Theodrakis (1989) determined that odd-sized minnows were attacked more often than those of average size within a school. It is hardly surprising, then, that such homogeneity exists among the members of fish school. Selection against oddity is thought to be the main reason for the lack of sexual dimorphism among schooling fishes (Landeau & Terborgh 1986).

A typical feeding frenzy of koi in an ornamental pond.

FEEDING BENEFITS

Group living also confers certain advantages of feeding. The multiplied vigilance of fish schools, while protecting its members from predators, also facilitates their discovery of food. Pitcher et al (1982) observed that minnows (Phoxinus phoxinus) located food more rapidly as their school size increased. This effect particularly benefits those species in habitats where food resources are patchy or unpredictable. In addition, the enhanced vigilance of fish schools toward predators means that each member of the group can spend less time in watching for danger and more time in feeding (Radokov 1973).

Schooling behaviour has proven effective at overcoming the territories of aggressive fishes (Foster 1985). Robertson et al (1976) observed on coral reefs that solitary striped parrotfish (Scarus croicensis) were excluded from feeding in the territories of damselfish (Eupomacentrus planifrons) while parrotfish in schools were not. In this case, schooling fish were able to greatly expand their resource base.

Major (1978) suggests that the schooling of predatory fish may have evolved as a countermeasure against schooling prey. He observed that jacks (Caranx ignobilis) in schools were more successful at capturing schooled anchovies (Stolephorus purpureus) than were solitary jacks, because large groups of predators are able to rapidly break up the school, isolating prey and thereby eliminating a confusion effect. Cooperative hunting is an important part of the social systems of mammalian predators, such as wolves or lions, although few examples exist among fish. Radokov (1973) cites several instances of cooperative hunting in perch.

Swimming in a school also offers some hydrodynamic benefits.

HYDRODYNAMICS AND ENERGY CONSERVATION

A third benefit of schooling behaviour stands apart from either feeding or the dangers of being fed upon. As residents of a liquid medium, fishes are subject to the laws of fluid mechanics. A swimming fish produces vortices -- eddies of current -- which surround its body and trail behind in its wake. Any subsequent fish must contend with this trail of vortices which alter the resistance of the water, either increasing or decreasing the fish's swimming efficiency. Weihs (1973) demonstrated that the vortices created by fish schooling in an optimal "diamond lattice" pattern, beating their tails in antiphase, significantly reduce the amount of local friction. Fish swimming in this formation move faster and more efficiently through the water. Some debate, however, remains over whether such an optimal spacing pattern is duplicated in nature.

Hydrodynamic advantages have been cited in several studies (Breder 1965, Weihs 1973) as sufficient cause for the origin of obligate schooling species. Breder (1965) also contends that the vortices produced by swimming fishes play a role in determining the acceptable size range of individuals within a school and the proximity of spacing between members.

Other energetic benefits have been attributed to fish schools, including one study claiming that fishes in schools consume less oxygen than do solitary swimmers, and another which found that small amounts of mucus released by fishes into their vortex trails help to reduce drag of school members through the water (cited in Shaw 1978).

Group living does not come without its costs.

THE COSTS OF SCHOOLING

Living in groups, while contributing distinct benefits to its members, comes not without its costs. The compact structure of schools may indeed reduce chance encounters with predators, but other studies demonstrate that the range at which prey is detected increases with flock or school size (Vine 1973). Large aggregates of prey attract predators, sometimes in droves.

As well, the intra-species competition for vital resources such as food, mates, and nesting sites also increases with group size (Pitcher et al 1982, Poulin & Fitzgerald 1989). Fish schools are not as wholly egalitarian as some researchers would have us believe. Major (1978) observed that the positions of predatory jacks within their school led to unequal access to food resources. While schooling jacks caught more prey, on average, than they would as solitary hunters, those at the front of the school were 10 times as successful as those in rear positions.

Group living also facilitates the transmission of disease. Many studies (particularly with birds and mammals) have shown that the spread of communicable diseases becomes a serious problem in large social groups. Additional drawbacks, such as cuckoldry and cannibalism of young, have been observed in other gregarious species (Krebs & Davies 1987) but not, to date, in fishes.

SUMMARY

Schooling behaviour occurs in many diverse groups of fishes and offers a range of benefits to its participants. Consequently, there is probably no single reason why the behaviour has evolved. Major benefits of schooling involve predator evasion, feeding gains, and improved hydrodynamics. While these advantages are tangible and well-documented, the benefits of group living are not universal. Otherwise, the number of species which exhibit life-long schooling would exceed the reported 25%. Indeed, the many predators which feed upon schools of fish -- including humans with our commercial fisheries -- demonstrate the alluring and sometimes vulnerable nature of group living.

By living in a school, then, is the herring really smarter than the rockfish? The answer comes as a resounding no. Each mode of behaviour has been tried and proven, via the grand jury of evolution, to be best suited for the optimal survival of an individual species.

REFERENCES

Breder, C. M., Jr. 1965. Vortices and fish schools. Zoologica 50: 97-114.

Breder, C. M., Jr. 1967. On the survival value of fish schools. Zoologica 52 (1): 25-40.

Cushing, D. H., and F. R. Harden Jones. 8 June 1968. Why do fish school? Nature 218: 918-920.

Foster, S. A. 1985. Group foraging by a coral reef fish: a mechanism for gaining access to defended resources. Animal Behaviour 33: 782-789.

Foster, W. A., and J. E. Treherne. 8 October 1981. Evidence for the dilution effect in the selfish herd from fish predation on a marine insect. Nature 293: 466-467.

Godin, J. -G. J., L. J. Classon, and M. V. Abrahams. February 1988. Group vigilance and shoal size in a small Characin fish. Behaviour 104 (1-2): 29-40.

Heczko, E. J. and B. H. Seghers. 1981. Effects of alarm substance on schooling in the common shiner (Notropis cornutus, Cyprinidae). Environmental Biology of Fishes 6 (1): 25-29.

Hoogland, J. L. 1979. The effect of colony size on individual alertness of prairie dogs (Sciuridae: Cynomys spp.). Animal Behaviour 27: 394-407.

Keenleyside, M. H. A. 1955. Some aspects of the schooling behavior of fish. Behaviour 8(2-3): 183-248.

Krebs, J. R., and N. B. Davies. 1987. An Introduction to Behavioural Ecology. 2d ed. Oxford: Blackwell Scientific Publications.

Landeau, L., and J. Terborgh. 1986. Oddity and the 'confusion effect' in predation. Animal Behaviour 34: 1372-1380.

Major, P. F. 1978. Predator-prey interactions in two schooling fishes, Caranx ignobilis and Stolephorus purpureus. Animal Behaviour 26: 760-777.

Moyle, P. B., and J. J. Cech, Jr. 1988. Fishes: An Introduction to Ichthyology. Englewood Cliffs: Prentice Hall.

Parr, A.E. 1927. A contribution to the theoretical analysis of the schooling behavior o fish. Occas. Papers Bingham Ocean. Coll. (1): 1 - 32.

Parrish, J. K. December 1989. Re-examining the selfish herd: are central fish safer? Animal Behaviour 38: 1048-1053.

Partridge, B. L., and T. J. Pitcher. 31 May 1979. Evidence against a hydrodynamic function for fish schools. Nature 279: 418-419.

Partridge, B. L. February 1982. Rigid definitions of schooling behaviour are inadequate. Animal Behaviour 30: 298-299.

Pitcher, T. J., A. E. Magurran, and I. J. Winfield. 1982. Fish in larger shoals find food faster. Behavioral Ecology and Sociobiology 10(2): 149-151.

Pitcher, T. J., and A. E. Magurran. May 1983. Shoal size, patch profitability and information exchange in foraging goldfish. Animal Behaviour 31: 546-555.

Poulin, R., and G. J. FitzGerald. 1989. Shoaling as an anti-ectoparasite mechanism in juvenile sticklebacks (Gasterosteus spp.) Behavioral Ecology and Sociobiology 24 (4): 251-256.

Radokov, D. V. 1973. Schooling in the Ecology of Fish. New York: John Wiley.

Robertson, D. R., H. P. D. Sweatman, E. A. Fletcher, and M. G. Cleland. 1976. Schooling as a mechanism for circumventing the territoriality of competitors. Ecology 57: 1208-1220.

Seghers, B. H. 1974. Schooling behaviour in the guppy Poecilia reticulata: an evolutionary response to predation. Evolution 28: 486-489.``````

Seghers, B. H. 1981. Facultative schooling in the spottail shiner (Notropis hudsonius): possible costs and benefits. Environmental Biology of Fishes 6 (1): 21-24.

Shaw, E. 1978. Schooling Fishes. American Scientist 66: 166-175.

Theodorakis, C. W. September 1989. Size segregation and the effects of oddity on predation risk in minnow schools. Animal Behaviour 38: 496-502.

Vine, I. 1973. Detection of prey flocks by predators. Journal of Theoretical Biology 40: 207-210.

Weihs, D. 26 January 1973. Hydromechanics of fish schooling. Nature 241: 290-291.

EASE YOUR CARBON CONSCIENCE

Sat, 23 Oct 2010 18:00:22 +0800

How best to lighten your travel footprint?

BEING an environmentally aware traveller used to be pretty simple - "take nothing but pictures, leave nothing but footprints" went the mantra. Now, even footprints are enough to make us feel guilty. Carbon footprints, of course.

For anyone not quite in the know, a small refresher: Your carbon footprint is the amount of CO2 you contribute to the atmosphere through your activities over a given time. For travellers, this largely translates to the way you get there and back. Transportation burns up a lot. This is common sense, of course. It doesn’t take a physicist to realize that driving your car requires more fuel per passenger than taking the bus or MRT, and that cycling produces almost no CO2 emissions by comparison.

Still, when one considers that each litre of petrol burned produces 2.3kg of CO2, some of the numbers stack begin to stack up alarmingly.

Let’s look for a moment at a one-way trip from Singapore to Penang (608 km) using six possible transportation methods. Here's how much CO2 you'd produce:

With global warming, high fuel prices and the prospect of climate change on everyone's lips these days - not to mention air travel usually demonised as the worst CO2 producer - maybe it’s time to think of some holiday alternatives. Even if you’re nowhere near the Lion City, think of these destinations as metaphoric. You can easily find your own parallels using the same means of transportation.

Four flight-free destinations from Singapore

IPOH (Malaysia)
Mode of travel: Train
Travel time: 10.5 hrs

Why Go?
Alongside its fame for white coffee and tin mining, Ipoh offers other attractions for the short-term visitor. It was once the second administrative centre for the British, and historic sites such as the Town Hall and Padang still reflect that past (the elegant old rail station is sometimes called "the Taj Mahal of Ipoh"). Even the museum of Perak is located within the mansion of a former tin tycoon.

Outside the city, there are jungle treks in the Menglembu Hills, rock climbing on limestone cliffs at "The Lost World of Tambun" and soaking in the Tambun Hot Springs. There's plenty of golf too - not the greenest of pastimes, admittedly. Ipoh is also a stopping off point for the Cameron Highlands, though you'll have to take a bus to get there.

Total Carbon Footprint: 26 kg CO2

KRABI (Thailand)
Modes of travel: Train to Hat Yai, bus to Krabi
Travel time: 19 hrs (with overnight stop in Butterworth)

Why Go?
A bit on the far side, but still possible without touching an airport, Krabi is often looked at as "Phuket, 20 years ago", highlighting its unspoiled (or at least less touristy) natural beauty. True, the international airport that was completed in 1999 has accelerated tourism, but it's still a secondary destination compared with Phuket or Koh Samui. Here, you have all the trappings that southern Thailand is famous for: Karst rock formations and green bays, sandy coves and coral reefs, quiet resorts with their own long-tailed boat transport, and all sorts of adventure activities, from sea kayaking to forest nature treks. It's also just a short trip to reach famous names like Phi Phi Island or Phuket.

Total Carbon Footprint: 46 kg CO2

NIKOI ISLAND (Indonesia)
Modes of travel: Ferry to Bintan, taxi to jetty, launch to Nikoi
Travel time: 2.5 hrs

Why Go?
Since its development in 2007, this small boutique resort off the east of Bintan has marketed itself with sustainable tourism in mind. Even its design, from solar water heating to the use of local natural materials (driftwood for construction and insulated roofs), insure a minimal environmental impact during your stay. That said, the resort doesn't skimp on luxuries. One visitor on TripAdvisor.com termed it the "Robinson Crusoe Ritz.”

Nikoi has all the trappings of a proper island getaway - white sands, coral reefs, sailing activities, rock climbing and mountain biking. The resort even organises games such as beach volleyball and capture the flag. Two thirds of the island retains its natural forest cover, and the owners, presumably, are committed to keeping it that way.

Total Carbon Footprint: 38 kg CO2

PULAU UBIN (Singapore)
Mode of travel: Bumboat from Changi Village
Travel time: 15 minutes

Why Go?
This island off Singapore's north-east offers a last glimpse of kampung life as it once was. Being closest to urban Singapore, it's also the greenest destination on the list. Except for the bumboat ride from Changi village, you'll probably walk or cycle throughout your stay (though local taxis are available). Highlights include the intertidal flats at Chek Jawa for marine life viewing, excellent mountain-bike trails (complete with wild monkeys), mangrove forests for fishing and wildlife, abandoned rubber tree plantations that look straight out from a Somerset Maugham story, and decent beaches for picnics and swims. There's also an orchid farm with local wildlife, and outdoor sports offered at Kampung Ubin, where you can stay in comfort.

Total Carbon Footprint: 6 kg CO2

Admittedly, for Singaporeans (like urbanites in most other world cities), favourite destinations are often still a plane flight away. So if you absolutely must fly, then consider some greener alternatives. Airlines like Cathay Pacific, British Airways, and Qantas offer volunatry extra fees (or the donation of air miles) to help ‘offset’ your carbon footprint. The money goes toward planting trees or funding environmental causes and charities.) For the frequent or obligatory flyer, this might prove another way to ease your carbon conscience.

A FEW TIPS FOR GREENER TRAVEL

1. Calculate your own carbon footprint before you go, using sites like www.carbonfootprint.com. Where you stay and what you eat and do, also affects your footprint.

2. Walking, cycling or sailing leave are carbon neutral. Shared/public transport is the next best thing. Private cars and air travel leave the biggest footprints.

3. Consider your hotel choices, and whether they are environmentally aware. Do they monitor energy use? Use chemicals? Conserve water?

4. Bring a water bottle and filtration kit. Avoid the wastefulness of buying (and discarding) water bottles.

Take rechargeable batteries.

6. When hiking, stay on marked trails and avoid damaging delicate ecosystems.

ALIENS AMONG US

Fri, 15 Oct 2010 14:12:56 +0800

Singapore’s most common birds don’t belong here at all, but are artifacts of human history

Long after the Raffles Hotel has crumbled to dust and the Padang is a jungle of high-rises, pieces of Singapore's early history will continue to flutter and strut around its streets.

Some of the island’s most common birds don't belong there at all. They are alien invaders, and over the decades they've hitched rides with humans to get to the island. Sometimes destined for dinner plates or for farmer's fields or simply to ease a new immigrant's longing for the birdsong of home... by ship and by air, by design and by accident, they made their ways to Singapore’s shores.

Mynahs, sparrows, crows, and pigeons are just some of the ten to fifteen exotic species which now call Singapore home. They have also become its most visible avian residents. Their familiar presence reflects not only their skill in adapting to new environments, but represents different periods of Singaporean history. In that way they could bee seen as living artifacts of Singapore's colonial past.

"It's hard to pinpoint the precise origin of these birds," says Navjot Sodhi of the Department of Biological Sciences at NUS. "But there are lots of interesting stories associated with their arrival here."

Take the House Crow, for instance. This grey-bodied bird (distinct from the dark black native crow and much rarer Large-billed Crow) arrived in this part of the world in the early 1900s as a crude form of biological pest control. Native to Sri Lanka and India, House Crows were brought to what was then British Malaya in an effort to control crop-eating caterpillars. They flourished and quickly moved beyond the agricultural fields they'd been brought to protect.

House Crows didn't arrive in Singapore until decades later. Several unsuccessful attempts were made to establish the species here, but it was only during the chaotic war years of the 1940s that the species finally took hold. Now you can find them everywhere across the island, roosting noisily in mangrove trees and rooting in dumpsters, a testimony to the species’ skill as a scavenger. Ironically, the once-useful immigrant is now routinely culled as a pest.

Biological Dispersal

This natural tendency for living things to expand their populations, not just in size but in range, is known as "biological dispersal". It's the reason we see magpie robins not only in Singapore, but from Pakistan to the Philippines, and why coconut palms are found on tropical shores the world over. (Plants can't move, of course, but they are seeded by agents which do: wind, animal hosts, or in the palm's case, water.)

However Nature does impose its limits. Populations can't expand their ranges uncontrollably. Climate and geography create barriers that are often impossible to overcome. A mountain range or a desert, an ocean or a river can effectively prevent a species from crossing into new territory.

That's why tigers live in Sumatra but not in Borneo (the sea crossing is too much, even for strong-swimming felines) and what keeps polar bears in the arctic and kangaroos in Australia. This isolation of populations is also the main driving force behind the evolution of new species.

Enter the Humans

But when humans enter the picture, all the rules of an ecosystem get thrown out. We bludgeon and modify the landscape into new forms, often driving out native species and creating perfect habitats for invaders.

The widespread clearing of Singapore's forests was ideal for the Javan Munia, a small songbird which arrived there in the 1920s. As a specialist in eating the seeds of lawn grasses, it thrived in the altered habitat and has become today the island’s most common munia.

Humans also disrupt ecosystems by bringing along these new species, either by accident or on purpose. A homesick Englishman in 1870s New York thought to introduce all the birds mentioned in Shakespeare’s plays into Central Park. Most died out after the first winter, but the European starlings did not. From a handful of birds released originally, they spread across the continent from Miami to Alaska, and now number in the hundreds of millions.

The White-vented Mynah, an everyday sight here from hawker stalls to city parks, is thought to have been introduced by a man involved in the caged-bird trade back in 1920. Even Sulpur-crested Cockatoos, natives of Australia, have established themselves in Singapore forests from once-captive ancestors.

The Shape of Things to Come

Unfortunately, such ecological disruptions often come at the expense of native species. Unchecked by predators or local competitors, an alien species can sometimes spread wildly out of control. Consider the rabbits in Australia or the eucalyptus trees in California, both of which became a local scourge after innocent or well-meaning introductions.

The result? Extinctions. Sometimes on a massive scale.

Hawaii was once considered among the world's richest reservoirs of unique bird life, but only 35% of the native bird species are alive today. Landscape changes, disease, predators, and competition from introduced species have wiped out the majority.

Singapore has lost 106 (about 30%) of the bird species that were recorded here a century ago.

And the process of alien invasion hasn't stopped by any means. One of the most recent arrivals -- the European House sparrow -- is still confined to the Pasir Panjang wet markets where it appeared a decade ago (presumably with a shipment of produce.) But judging by this same bird's success as an immigrant to North America and Australia, it might soon be a common resident across the island.

So the next time you're awakened by the noisy dawn chortling of the Koel, consider the fact that you’ve met yet another recent immigrant. In just a decade this crow-sized bird managed to colonise the entire Malay peninsula, partly because it takes over the nests of crows and mynahs, turning those unwary residents into hapless surrogate parents - much as cuckoos do in Europe.

Mirroring its human populace, arrivals past and present make up the increasingly cosmpolitan look of Singapore's birds. For better or worse, these alien invaders are here to stay, each one of them contributing a colourful immigration story to Singapore's history.

TERMITE TOWERS

Mon, 23 Aug 2010 14:24:27 +0800

Australia’s Northern Territory is home to nature’s ultimate highrise

Step over, Burj Khalifa. Forget Taipei 101 or Toronto’s CN Tower. There’s a highrise five times the height of the Empire State Building which takes up eight city blocks and houses a million residents. And it’s sitting at the top end of Australia. If this is beginning to sound the stuff of dreams – or a Spielberg sci fi thriller - then let me clarify. We’re talking termites, here. As for the size – it’s relative.

Cathedral Heights

One of the more striking features of the landscape south of Darwin, Australia, is its Cathedral Termite mounds. They rise, just off the highway in parts of Litchfield and Kakadu parks, like stone monoliths from the dry savannah. Some of them tower seven metres from toe to top.

From the outside the tower appears lifeless, like rock or concrete, but break off a piece and an instant repair crew will swarm out. Worker termites. Harmless enough to us, but that sticky, honey-scented sap they secrete on your finger would be a debilitating acid, if you were a hundred times smaller.

Termites, or “white ants” as they’re sometimes mistakenly called, belong to the class of social insects that includes bees, ants, and wasps. They’re found all over the world, perhaps best known for the damage they cause to wooden homes. Here in Northern Territory, it’s their architectural prowess that brings them fame. Despite a diminutive 5 mm size, tens or hundreds of thousands of termites working together can raise a structure that dwarfs comparative human accomplishments. They grow just 2–5 cm a year, which dates some of the mounds in the parks at more than a century.

As with human skyscrapers, termite mounds attempt to create a near-perfect artificial environment. They offer protection from bushfires, from wet-season floods, and from relentless tropical heat. All this from a mixture of dirt, chewed grass, and termite dung. It’s the grass which is the key component. The insulating qualities ensure that the inner thermostat remains an even 30° C, year round. Even under the baking Aussie sun.

Magnetic Marvels

As if giant termite towers weren’t enough, Australia’s Top End also plays host to another insect oddity – magnetic termites. A field of these mounds looks even eerier than the cathedral variety, especially at sunset. Tall, thin slabs, most of them facing the same direction (aligned from north to south) and looking for all the world like a field of gravestones. Think Flanders Fields. The termites apparently orient their homes along the earth’s magnetic field to maximize cooling, so the theory goes. How they tap into it, though, is still a mystery.

Australia, incidentally, is the only place in the world you’ll find them, and Litchfield Park has arguably the most spectacular examples of them in the world.

Both Cathedral and Magnetic termite mounds are on the itineraries of many day trips to Litchfield and Kakadu. Self-drivers will also find them well sign-posted from the highway (“Termites 18 km”). For any visitor to Darwin even remotely interested in nature’s wonders, standing next to such supreme animal architecture is awe-inspiring, and well worth the trip.

So the next time some human metropolis chortles about a new height record broken, the ‘tallest this’ or the ‘biggest that’, smile a little and spare a thought for the humble termite.

TRAVEL NOTES

GETTING THERE:
Darwin is a four hour flight from Singapore, four and a half hours from Melbourne or Sydney, two and a half hours from Bali’s Denpasar. Most other major cities require rerouted flights. Jetstar airways is likely your cheapest bet in getting there.

Kakadu and Litchfield parks make an easy day trip from Darwin. Hire a car, or take one of the many ‘adventure tours’ on offer.

WEEKEND GETAWAY:
A trip to Darwin and Kakadu offers a civilized combination of natural splendours and city comforts. The best time to go is the dry season, from late April to early October. (Parks become partly inaccessible during the wet season.)

STAY: Accommodation ranges from the grand (Darwin’s Crowne Plaza for S$250 a night) to the budget (Frogshollow Backpackers at S$25). For the more adventurous, a three night-, four-day tenting tour of Kakadu and Litchfield parks is S$700.

DO: Darwin itself offers plenty of amusements. City-wise, there’s the Skycity Casino, sunset markets at Mindil Beach, Crocodylus Park, museums, galleries, and fish-feeding at Aquascene. In the outback of the parks, the wildlife and rugged landscapes offer days of possibility.

This article article was first published in TODAY.