Less than four hectares in size, it is surrounded by suburbia, which continues to develop around its edges.

Its main purpose is water collection and diversion.

But it has also been planned for wildlife, successfully filling a useful and appreciated role as a wetland for waterbirds and other aquatic wildlife, as well as for native plants.

Most of the trees, shrubs, grasses and rushes growing there are indigenous to the Ballarat region.

They provide suitable cover for numerous birds.

The total number of birds on the list for Paul's Wetland is about 80 species.

A dozen or more can usually be found on any visit.

A group of bird observers found more than 20 last Sunday morning.

Ducks spotted included grey teal, hardhead and black duck.

Other waterbirds were the little pied cormorant, little black cormorant, black swan, hoary-headed grebe, coot, dusky moorhen, white-faced heron, silver gull and purple swamp hen.

As is the case with many city and town wetlands, the occasional domesticated duck is released there to join the native species and to be fed by local residents.

Other birds are found as well, such as the New Holland honeyeater, red wattlebird, rainbow lorikeet, crested pigeon and galah. Greenfinch and goldfinch are sometimes seen.

Many other species stop for a day or two.

Rare visitors on the list include darter, common sandpiper, flame robin, pelican, freckled duck, black-shouldered kite, spoonbills and crakes.

A bird of special note at Paul's Wetland is Latham's snipe, a migrant from Japan.

Small numbers visit from about September through until about early autumn, depending on water levels.

Suitable habitat for the snipe exists particularly in the upper, well-vegetated marshy parts.

The current wetland reserve is not quite on the site of the original swampy drainage line that became "Paul's Drain" as nearby development increased.

The 25mm black bulldog ant can be found at the North Gardens Wetlands, near Lake Wendouree.

This is surprising, as this large ant is more a creature of lightly forested places, rather than planted man-made environments.

The current wetlands area obviously provides the big ant with suitable habitat.

The large size and large pincers make this ant a creature to beware of.

Its sting - which is in its tail - is extremely painful. There is no need to disturb them - just move on if you see them on the path.

I found this 15cm long caterpillar decimating a small eucalyptus tree in Woowookarung. Any idea what it is? It's huge!

R.L., Mt Clear.

This is a mature emperor gum moth caterpillar, sometimes known as the gum emperor moth.

At that size it will soon pupate, shrinking itself into a tough, furry, egg-shaped cocoon about 30mm long.

These cocoons are seen more often than either the caterpillars or the moths.

The small spiky protuberances are presumably part of the caterpillar's protection.

Pupation could take a year or more, with the large, handsome brown moths emerging in summer.

The moth lays its eggs on gumleaves, and this is the caterpillar's food.

Tender young eucalypt leaves are preferred, so the caterpillars spend most time in the upper parts of trees.