Under state government plans, this humble patch of scarce inner-city wilderness will be transformed into the mouth of one of the most expensive pieces of infrastructure Victoria has seen. The east-west link tunnel will apparently shave 10 or so minutes off some drivers' travel times, yet this will come at a high price. For now the fairywrens and their tall companions are busy sorting through the leaf litter. Learning about the birds of Royal Park is exciting - like discovering a new and intricate world. They cease to be merely part of the scenery once their unique personalities are discovered. Take the blue-faced honeyeater, who likes to visit the aviary at the zoo. He goes to see the other blue-faced honeyeaters on the inside. They can sometimes be seen talking through the wire as he shares information about the outside world, perhaps trying to understand the limitations of captivity. Alexis Beckett, a member of the Friends of Royal Park, says one of her great joys is to see a gum tree laden with teenage magpies piping out feeble attempts at song. Because of Royal Park's large size (170 hectares), magpies, currawongs and little ravens are able to live in flocks rather than as individuals. This is great for young magpies, who are able to learn the local magpie song from adults and get a chance to practise their nest-building skills. It is not only Royal Park's size and proximity to the city that makes it special, but also its ruggedness in contrast to the formal planting of other city parks. It means it can supply a variety of birds with their needs, and that no one species can dominate. Beckett tells me about the rarely seen mistletoebird, which is able to come to the park for a seasonal feast of sticky seeds.

Over the years various groups have tried to eradicate the non-indigenous plants, yet the local birds don't share these prejudices. Eastern rosellas gorge on the seeds of the plane trees in spring; dainty little red-rumped parrots nest in the hollows of elms. Beckett also remembers that before the pine trees were removed, we had regular winter visits from flocks of brash yellow-tailed cockatoos who came for a feed of young pine cones. John Cotton was an urban birder with a seminal story. In the 1840s he arrived by ship into Port Phillip Bay. During the voyage, he wrote verses that he liked to think emulated Wordsworth, but according to his brother back home in England, they fell a bit short. He could, however, draw a good bird. Cotton set out to compile a guide on the birds of what was then southern New South Wales. He, his wife and their 10 children settled on the banks of the Goulburn River to raise sheep, but on his frequent supply trips to Port Phillip, he would journey down the Moonee Ponds Creek. The birds of this new land infatuated him ''Amidst th' Australian forest wild a gleam''. He documented 156 birds in the Royal Park area; Beckett's list is only at 60. Cotton, however, never got to finish his project; he died three days short of his 48th birthday. His work was lost for more than 130 years, until his great-granddaughter, Lady Casey, decided to uncover it. His detailed sketches and notes give us an understanding about the types of great birds that used to enjoy this area. They also make me realise how resilient some of these Royal Parkers have been to stay on their land, in their country. The Friends of Royal Park are concerned that the construction of a cross-city road tunnel under Royal Park will reduce the park's biodiversity and indigenous vegetation. They are concerned that we will lose this unique and magic world within our city.

According to just-released state government impact documents, the entire wetlands lie within the construction boundaries, with the western waterhole already earmarked for permanent acquisition. The main waterhole is also in danger. ''Should the entire wetlands area be required for construction, small numbers of birds would be displaced to the nearest suitable habitats,'' the report says. There is certainly no guarantee that Trin Warren Tam-boore will remain at all. The beautiful great egret, with its delicate stature, is shy - as soon as he sees me approaching on my bicycle, he takes to the sky. What will he think of the five years of digging and drilling to come? And what of migratory birds such as the rare hardhead duck - listed as vulnerable by the Department of Sustainability and Environment - who depend on the surety of water at Trin Warren Tam-boore to complete their passage? The path, the bridge, the trees, the grasses, the water, its movement, the wind, the clouds. A sudden flap of wings on water and then a swoosh as a chestnut teal passes overhead. I look up to see a glorious scene as birds in groups of twos, threes and fours take to the sky in unison. Ten seconds later, it's all over as the larger birds fly into the distance and the ducks come in to land. The fairywrens find a branch and continue to chirp. The whole waterhole hierarchy has been restructured.