The Joy of Sewage.

Trip to a sewage works anybody? No?

How about getting up at 4.30am two days after Christmas? No?

Still not interested?

I know! Let’s get up at 4.30am two days after Christmas and visit a sewage works!

So here I am, early in the morning, possibly the only person awake for 500m in any direction, getting ready to drive to the Werribee sewage works – rebadged as WTP (Western Treatment Plant), but it’s not fooling anybody.

The trip along the Geelong Road was unsurprisingly quiet. Yet even here there were things to be seen. Mists hugged some fields and fled from others. Some fields were bare, others clothed in white. There seemed to be no pattern. Cows floated, seemingly legless in the mist. The scene looked African. On a side road, a fox dashed from the mist, seeking food, a hare froze, seeking sanctuary in stillness. The mist cleared to show the You Yangs, Melbourne’s asymmetrical western hills. If these were the Pap’s of Melbourne they would be scheduled for cosmetic surgery.

Werribee lie between Melbourne and Geelong, in a flat coastal area. The You Yangs cast a rain shadow over the sewage plant. In the past this helped with evaporation, even if it did nothing about the smell. Each day Werribee receives a nutritious, if rather fragrant, gift from western Melbourne. Almost 500 million L of the stuff each day.

In the past this was treated in the open air, and property values in the nearby town of Werribee reflected this. Now, a much larger covered treatment plant has reduced the aroma, although I am not sure if there has been a property as a result.
But the simple fact of the matter is that all this waste, processed for over 100 years, has led to an ecosystem bursting with life. Awash with it really. Natural coastal lagoons were enlarged and linked and as the nutrients flowed, life flourished. Flourished to such an extent that it is listed as a wetland of International Significance under the Ramsar Convention. Not bad for a sewage works, and the management was no doubt flushed with pride when the listing was made.
And finally we are at the point of this. Birds – often in huge numbers can be found here. As drought has dried other wetlands, the 500 million L of water guarantees that this wetland is actually, well, wet! 50,000 Pink Eared Ducks. At times up to 30% of all wildfowl in Victoria. Significant numbers of migratory waders – Red Necked Stints, Curlew Sandpipers, Sharp-Tailed Sandpipers. Rails. Ibis. Black Swans. Whiskered Terns. Growling Grass Frogs (I’m not making this up!). At times you forget you are at a functional sewage works – you half expect a man in pale trousers and a blue shirt to pop out of the bushes. “Nice shirt, Sir David” “Thank you, and get out of my camera shot!”

As the tide in Port Phillip Bay rises, the birds are pushed off the bay and onto the “tanks” ie lakes in the sewage works. They roost and feed. One tide pushes then off the bay, another tide fertilizes and provides food. The waders are at the end of a journey from their breeding grounds in the Northern Hemisphere – far north. They will have flown south through Korean, stopped in Northern Australia and now settle down to some serious feeding courtesy of Melbourne’s sewage.

The fact that the sewage pools are called tanks adds to the military feel of trapping these birds. Dawn meetings at secret locations. Pre-trip recces of roosting sites. 4WD vehicles filled with strange bags and odd boxes. People wearing pale clothes. Detailed radio communications. Cannons.

Real cannons, explosive, loud thundering type cannons. They are used to deploy (see you can’t avoid the military feeling!) large nets over flocks of roosting birds. The nets are concertinaed on to themselves and the cannon dug in (!) behind this line. Large projectiles are attached to the front/top of the folded net. Once the nets are set there follows a period of waiting for the birds to return. Once they are in front of the net, but not too close and not too far the net can be fired. There is a countdown that really does go “Armed, 3,2,1 Fire!” The cannons are fired and the net shoots out over the birds (well that’s the plan anyway). It’s all rather spectacular. It’s loud and it causes all hell breaks loose, both among the flock of birds and the attending birders.
At this point the safety of the birds comes first. Gentle souls would be advised to avoid this part of the day. Fragile egos will be trampled on, self confidence shattered. The timid would be best off seeking shelter in the long grass. People who should know better, and people who should not be doing it at all, sprint to the net. At this point one of life’s 3 golden rules comes into play. These are: 1. Never kiss your sister. 2. Don’t eat the yellow snow. 3. Never, and I mean never, stand on the net. It’s the last one which is most important here, although you should never forget the other two either!

If it is a dry catch (and it rarely is) the net can be left in place, and the birds covered with shade cloth. If the catch is wet, the net and birds are rapidly moved onto dry land, then covered. The shade cloth calms the birds down and they are extracted a bird at a time. This can take a little while if you have caught 500+ birds. The knees suffer. The back aches. Extraction is like trying to undo a 3D jigsaw puzzle where the pieces keep moving and some of the pieces try to bite you! The extracted birds are moved to large, shaded, keeping cages. For a while calm descends on both birds and birders. The birds take comfort in the darkness, people take comfort in food. People gather in small groups. They drink coffee, eat Christmas cake, recover.

If catching the birds smacks of a military operation, the next stage looks like some form of industrial production line. Processing the birds involves a number of stages. The birds are banded (ringed if you are in the UK), and flagged. The rings are unique to each bird, the orange flags are unique to Victoria. The birds are measured, weighted, have their feathers checked to age the bird and are finally released. This is paying attention of a scientific order of magnitude. Even for the more common species, each new measurement is a data point on the road to understanding. A way point to knowledge.

One of the key measurements taken is the number of juvenile birds. This is used to measure how well the bird has done on its northern breeding grounds. The more juveniles, the better the year. This is not quite true as the birds could have had a good year on the breeding grounds, but lost most of the young on the trip south. But the more juveniles that are being recruited into the population the better. This of course does not apply to housing estates and cinemas, where generally people are more than happy to see very few juveniles about! Juveniles can often be told by their plumage (again there is a human parallel), differing patterns and colour grades mark then out. They probably listen to loud music as well. When you hold a new Red Necked Stint in your hand you cant fail to be impressed. About 20 weeks ago this bird was an egg in the northern hemisphere, probably in Siberia and now it’s feeding up on the south coast of Australia.

That’s an impressive journey for a bird the weighs about grams! At 25 g per bird you would get about 18 to the pound or about ¼ of an apple! When you have them in the hand it is remarkable to think of what they can do. Migration distances for old birds would get them way out past the moon. And that assumes they fly in a more or less straight line and that they never pop down to the shops because the run out of milk or some other stint essential.

Sitting there taking the measurement of bird after bird, normally of the same species, you can’t fail to notice the variation between them. Some have longer wings, shorter beaks, fatter legs, longer bills, bigger heads. These measurements are being taken on a single species, which means you are measuring the feedstock of evolution. Variation. Here it is, in the flesh, in the feather, in the bill. It’s a remarkable thing to actually witness because we don’t normally detect such differences. I think it’s a thing all biologists should do at some time, and a thing that all creationists should do right away.

Variation, competition, time, biodiversity. The Red Necked Stint is closely related to 87 other wading birds. And they all came into being because of variation, competition and time. It’s a recipe so simple, so powerful, so well established, that it’s hard to understand why it’s in the slightest way controversial. I suppose that many people are simply not exposed to the idea, but for many there is no excuse. “Stupidity is a condition, but ignorance is a choice” (Thanks Rich!)

Before the cannons roar and the after final extraction a kind of peace can be found. And into that peace things will walk, fly and crawl. When you are in interesting places, being quiet and keeping your eyes open you see things. When I returned to the car the get my lunch, calling from the tall vegetation was a male Golden-headed Cisticola (which is pronounced “sis-tickaler” not “sis-t-cola”). It’s a cracking little bird with a cracking long name. It’s not rare, it’s common. But that is of no significance.

It’s surprising what you can see, what you can learn by getting up early and going to sewage works. Put it on your to do list now.

2 comments:

RBenz said...

This sounds like almost as much fun as running around your back ponds with large nets trying to catch wading birds so you can wash of their feet to find out how plants might have arrived at the Galapagos Islands. ---


"One of the subjects which gives me most trouble for my work, is means of distribution in the case of species found on distant islands; I have lately been trying the powers of resistance of seeds to sea-water,—their powers of floating—the number of living seeds in earth & mud &c &c.— Would you render me a little assistance in this line? My walking days are over, never to return. I want to know whether on a wet muddy day, whether birds feet are dirty. I am going to send my servant out with some keeper & he shall wash all the partridges feet & save the dirty water!!

But I want especially to know whether herons or any waders (we have no ponds hereabouts) or water-birds when suddenly sprung have ever dirty feet or beaks? I found in 2 large table-spoon full of mud from a little pond from beneath the water 53 plants germinated.—f14

From a letter to T. C. Eyton, 31 Aug [1856] from C.R.Darwin.

Anyway, as you said, data is the thing. It is the evidence. It is the way we know. Of course, as we collect more and more data, the understandings we have come to accept might change, but that is what makes science different from beliefs. You are right, we all need to experience this sort of thing. thanks. RB

Thanh Le said...

may i know what is this activity? is it opened for public registration etc. would like to get my son involved to learn about nature. thanks!