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LIME KILN BAY : INCREASING BIO-DIVERSITY
By David Waterhouse
for Oatley Flora and Fauna Conservation Society
June 2003

When the weeds were cleared from upper Lime Kiln Bay a few years ago and a new wetland created by Hurstville City Council in an attempt to improve the quality of water flowing into Georges River, it was interesting to observe if the new habitat would attract aquatic fauna. What would visit the area first? Would any water birds or other noticeable fauna become permanent residents? Would any unusual species unrecorded in the Oatley/Mortdale district appear or perhaps re-establish themselves after decades of absence? All these were intriguing questions to the interested local naturalist.

When I first started to make fairly regular visits to the "new improved" Lime Kiln Creek/Bay wetland in January 2001, I soon learnt that the place had become a haven for several dozen Chestnut Teal and a few Pacific Black Duck. There was also a pair of Grey Teal amongst them. People fed these ducks and conditions suited them, so they stayed. Their numbers tend to fluctuate between a couple of dozen to forty or fifty, occasionally more. This includes all the species, with Chestnut Teal in the majority.

Each year, from August to April, ducklings may be seen of both Chestnut Teal and Black Duck, so some families must nest somewhere close by. They are difficult to find nesting as they are very well concealed. The nearest I have been to finding a nest so far is in September 2002. A female Chestnut Teal was seen crossing the track from Lime Kiln to the adjoining Oatley Park with eight tiny ducklings, obviously just hatched, following closely behind. The mother led her brood to the shallow water of the mangroves and reeds close to the open pool section of the wetland. She must have nested amongst rocks on the bush-covered slope above the track or possibly in one of the big hollows of the Smooth-barked Apples. Obviously they managed to elude the prowling foxes at least sometimes. Not all the ducklings of the teal and Black Duck survive. Often you will see four, three or two ducklings following their parents where once there would have been nine or ten. Both male and female Chestnut Teal attend their young, whereas only the female Black Duck accompanies hers as a rule.

Back in January 2001, there was a Little Pied Cormorant on a grid between the main macrophyte pool and the thick reed bed downstream. This was nothing startling. There are still a few around Oatley on the Georges River and its inlets, and even on the pond in the Oatley High School campus. Much more surprising was the sight of an Azure Kingfisher close to the small stream which forms an overflow beside the sandstone escarpment between the two open pools. This is definitely not a typical Oatley species. I haven't spotted another one since.

Upstream from the pond with the small island dominated by Swamp Oaks (Casuarina glauca), there are still some Water Skinks and Water Dragons basking on the rocks around the trash rack in the warmer months. They have probably always been there. In most months on warm days, but especially in Summer, there are at least eight species of Dragonflies and Damselflies present around the main pools and along the banks of near-by creeks. These probably colonised the area quite early on, soon after the wetland was established.

In mid March of 2001, I made my first sighting of a Clamorous Reed Warbler in the sedge beds of the main pool. Now there are two or three pairs present in the Summer and they will most likely breed each year. By May the first sightings of Dusky Moorhens were made; they too breed each year. There are usually a few birds about at any time, but as yet no more than six birds have been recorded. I spotted the first immature birds soon afterwards, so they probably bred that summer. The next new species to be noticed that year turned up in late September when a pair of Wood Duck with four young were seen on the main pool. They have returned occasionally since then, but no Wood Duck seem to have established themselves on a regular basis to date. Also seen at this time was a Sacred Kingfisher perched on the limb of a dead Casuarina overlooking the main pool, and a White-faced Heron which drifted into the pool area at evening time to feed in the shallows.

By the first half of 2002, Purple Swamphens had put in an appearance and they came to stay. A couple of pairs are probably resident and, like the moorhens, they produce young regularly now. There was a big drought that year, both on the coast and inland. In July, five Pacific Herons visited the wetland and one remained for several days. These birds usually only visit coastal areas in times of inland drought. Also in that month, a Great Egret was very conspicuous around the open pools, but it too only remained for a few days. Great Egrets can often be seen in ones or twos further downstream on the mudflats of Lime Kiln Bay, but so far this is the only visit I know of made by this bird to the recreated wetlands. That August, a pair of Hardhead (White-eyed Duck) could be seen on the main pool and they have re-appeared several times since.

I have heard from other people before the wetland was re-created that Red-bellied Black Snakes still occurred in the vicinity of Lime Kiln Creek, but had never seen one until late September 2002 when one crossed to wetland from the rocky slopes close by and swam into the main pool. It was probably looking for frogs. After rain, two or three species of frogs can be heard and, judging by the noise, they must be quite plentiful.

One of the biggest surprises came in October 2002 when, quite by chance, I spotted a tiny Baillon's Crake (Marsh Crake) on a part of the main pool which was starting to dry out. This bird is so shy as a rule that it is seldom seen at any time. I've seen one (same bird?) several times since, observing one bird on one occasion for about 20 minutes. This is again a rare bird for Oatley and quite unexpected in most places in Sydney. Already, the variety of waterbirds and other aquatic fauna to be seen was starting to creep up. Perhaps the little crake will become a permanent resident too.

Towards the end of October, a single Great (Black) Cormorant was perched with two Little Black Cormorants on the limb of a Casuarina tree. The fourth Sydney cormorant, the Large Pied Cormorant, can sometimes be seen further downstream amongst the mangroves, but it has not yet been seen near the ponds as far as I know. It tends to prefer marine or mangrove environments. On the same day, a Latham's Snipe was "put up" from the small wet patches along the cliff line rivulet which flows between the two ponds. It was close to where the Azure Kingfisher had been seen the previous year. In the following month, four more snipe were seen on the same evening's walk and an odd one or two was about for several weeks while the water levels were low and muddy patches were exposed, ideal habitat for the probing bills of snipe. I know of nowhere else where snipe have been seen around Oatley, except a single specimen at the Moore Reserve wetland at the same time as the first Lime Kiln Bay sighting.

In December 2002, a single Little Grassbird was heard calling from a clump of sedge. It has been heard several times since, but apart from a possible glimpse, not yet fully sighted. Later that month, an Australasian Grebe was present on the main pool after the water level had topped up a little due to a recent downpour. There are now sometimes two or three birds present.

In January 2003, a Long-necked Tortoise was spotted on a snag near the pond above the bridge. This could have been introduced by human agency, but it was quite shy and alert to an approaching intruder. It has been seen since in all three pools. Perhaps several of these aquatic reptiles are present and maybe they are wild not introduced specimens.

The next new bird species to be seen was a pair of Royal Spoonbills on the main pool. I first saw them in early February 2003, but other people had been seeing them since early January. They were most likely the same pair which often haunts the muddy foreshores further downstream beside the mangrove-fringed section of Lime Kiln Bay. The first Coot was observed in mid April 2003 and it was still in evidence at least until June.

In conclusion, it is obvious already that the number of observable wetland species has increased quite steadily in just a few seasons over a two and half year period. The relatively small artificial wetland is playing a significant role in attracting species which have long been absent from the Oatley environment and we can expect a few other surprises and "firsts" for Oatley in the coming years.

 


PLANTS OF LIME KILN BAY WETLANDS
(Alan Fairley March 2003)
*Alectryon tomentosa
Alternanthera denticulata
Baumea articulata
Bolboschoenus caldwellii
Bolboschoenus fluvatilis
Carex appressa
Casuarina glauca
Christella dentata
Commelina cyanea
Cymbopogon refractus
Cyperus congestus
*Cyperus eragrostis
Cyperus exalatus
Cyperus polystachyos
Cyperus sanguinolentus
Dianella revolute
Geranium homeanum
*Glochidion sumatranum
Hardenbergia violacea
Isolepis nodosa
Juncus continuus
Juncus kraussii
Juncus usitatus
Lomandra longifolia
Melaleuca linariifolia
Melaleuca styphelioides
Persicaria decipiens
Persicaria hydropiper
Persicaria lapathifolia
Persicaria orientalis
Phragmites australis
Schonoplectus validus
Syzygium paniculatum
Themida australis
Triglochin procerum
Typha orientalis
Viminaria juncea
Viola hederacea

 

 

 

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