The main feature of the Moggill Creek Catchment is the creek system that formed the area. It is dominated by Moggill Creek, which combines the flows from Gold Creek and its Reservoir and a few smaller mainly ephemeral tributaries.

Where Moggill Creek joins the Brisbane River, as it flows through Casuarina Park, it is tidal and the water has varying levels of brackishness depending on the creek flows and the salinity of the water being pushed back from the river with the twice daily tides. Here there is practically no aquatic vegetation and the banks of the creek are heavily eroded and the water is constantly turbid.  The local Catchment Group is assisting in stabilising the banks with appropriate trees and plantings of Lomandra.

There are many fish that can be easily seen in this part of the creek dominated by Mullet and Fork-tailed Catfish. The Mullet feed on the surface scum which contains pollen and a few micro-organisms on which they feed. The catfish are scavengers and eat both plant and animal scraps washed down the creek. Because of the lack of suitable habitat there are few small species, but shoals of the young of several salt-water and brackish species are often present.

As you go further up the creek as it winds through the urban area and around the Kenmore High School the tidal affect is lost and the habitat improves with several native and exotic aquatic plants present. The bottom of the creek is stony, and snags and a lot of decayed vegetative matter (mulm) is present which provides an excellent habitat containing food and a suitable spawning medium for a few species. Here Platypus can be seen and the range of fish species is much larger.

Sunrise on Gold Creek at Adavale St. Brookfield Photo: Ed Frazer

The main feature of the Moggill Creek Catchment is the creek system that formed the area. It is dominated by Moggill Creek, which combines the flows from Gold Creek and its Reservoir and a few smaller mainly ephemeral tributaries.

Where Moggill Creek joins the Brisbane River, as it flows through Casuarina Park, it is tidal and the water has varying levels of brackishness depending on the creek flows and the salinity of the water being pushed back from the river with the twice daily tides. Here there is practically no aquatic vegetation and the banks of the creek are heavily eroded and the water is constantly turbid.  The local Catchment Group is assisting in stabilising the banks with appropriate trees and plantings of Lomandra.

There are many fish that can be easily seen in this part of the creek dominated by Mullet and Fork-tailed Catfish. The Mullet feed on the surface scum which contains pollen and a few micro-organisms on which they feed. The catfish are scavengers and eat both plant and animal scraps washed down the creek. Because of the lack of suitable habitat there are few small species, but shoals of the young of several salt-water and brackish species are often present.

As you go further up the creek as it winds through the urban area and around the Kenmore High School the tidal affect is lost and the habitat improves with several native and exotic aquatic plants present. The bottom of the creek is stony, and snags and a lot of decayed vegetative matter (mulm) is present which provides an excellent habitat containing food and a suitable spawning medium for a few species. Here Platypus can be seen and the range of fish species is much larger.

Long-finned Eel (approx. 1.2m) Photo: Ed Frazer

The largest species is the Fresh-water Eel, which grows to 1.5 metres. These eels are somewhat territorial and will go overland in damp weather to find a new territory in farm dams where they live quite well. We have had them arrive in our nursery ponds and in past years our production manager caught them and produced jellied eel, which was a delicacy in his youth in England.

We used to see schools of around 12 Mullet in the big ponds alongside our property on Adavale St. 30 years ago but haven’t seen them recently. They were quite big fish and I am not sure if they were Fresh-water Mullet or Sea-mullet which venture into freshwater.

Another common fish in this reach of Moggill creek is the Eel-tailed Catfish, which grows to 80cm and weigh 8kg although I have never seen one that size in Gold Creek. While not a schooling fish, a large number can be attracted with bread or a suitable fish food and they will come to the surface in a feeding frenzy. They mainly feed at dusk and through the night aided by their sensitive long whiskers. They have a spectacular breeding method involving building a circular nest up to 2 metres in diameter where they expose and clean the stones on the bottom of the creek. Here they lay about 1000eggs which the male fans for 7 days until they hatch. Eel-tailed catfish are white fleshed and reported to be excellent eating, but my only experience of eating them was when my then 8-year-old son came home with a Huckleberry Finn style string of catfish he had caught and insisted I cook them. They were inedible as the flesh had a strong muddy overtone.

Eel-tailed Catfish (Approx. 45 cm) Photo: Ed Frazer

One day he also came home with a huge Silver Perch. I forget the actual weight, but it was certainly snapper sized. We later found out from Brian Leahy that several Silver Perch fingerlings were released in the Gold Creek Dam and this one was obviously washed over the spillway. We kept it alive in one of our troughs and later released it. Silver Perch, while a native fish, breed only after a substantial flood and need conditions that would not be replicated in our catchment. I recently saw another smaller Silver Perch when feeding the catfish. It was probably washed out from a farm dam as the species is a popular one for stocking farm dams.

As you go further up Moggill Creek to the junction with Gold Creek, the aquatic vegetation increases and provides a habitat suitable for many smaller fish species. While much of this vegetation is exotic it never-the-less supports a substantial population. Unfortunately, most native aquatic plants cannot tolerate elevated phosphorus levels, which are a feature of settled areas and while our creeks are some of the most pristine in Brisbane, the creek picks up enough phosphorus from septic systems and horse manure to reduce its suitability for the few native aquatic plant species, such as Myriophyllum species and Limnophilla indica, that provide excellent habitat for the breeding of many native fish species.

Some of the best suited species in this part of the creek come from the Gudgeon family. These are mainly about 4-5cm fish that breed by laying eggs on stones or submerged wood. They are attended constantly for the short time they take to hatch. In good conditions they can breed several times a year. They stay around the edges of the creeks often hiding in the vegetation darting out to catch any small prey as it passes by.

Another group in this reach of the creeks are the Ornate Rainbowfish (5cm) and their allied Australian Blue-eyes. The Rainbowfish is a prized aquarium fish that has all the colours of the rainbow in tiny reflective scales. It is a mainly mid-water to surface dwelling fish that feeds on micro-organisms and algae which are scraped off the plants and stones. They are unusual in their breeding as they lay just a few eggs a time over several days so there are always fry of different ages present. They deposit sticky eggs among fine leaves of aquatic plants or on the fine roots of trees such as weeping willows, which grow prolifically on the edges of creeks. The Blue-eyes (3cm) are noted for their brilliant eyes and yellow flag-like dorsal fins. They used to be common in the creek and 40 years ago my son and I used to take our punt on the creek at night and could net them out with a small hand net as they “slept” near the surface.

A common smaller fish along this part of the creeks that has prospered from the increased fertility is the Australian Smelt (7.5cm). It is an elongated schooling fish that is fast growing and it matures in 12 months. It scatters eggs on the stony floor of the creek and they take 10 days to hatch.

While Moggill Creek peters out to a small headwater in Upper Brookfield Valley, Gold Creek starts from the Gold Creek Reservoir. Here the water conditions are different; static water, which is pretty much pristine without the elevated phosphorus levels of the creeks below.  These conditions are excellent for Gudgeons and several other small natives, but the overall fertility is much lower than the lower reaches of the creek. The dam does provide a reservoir of fish that is important for repopulating the creeks after prolonged drought where the creeks have practically dried out.  Under flood condition some fish, fry or eggs are washed out of the dam and because all the creeks are interconnected in flood times, the fish can work around the edges of the flood water and repopulate depleted areas.

It is during times of flooding that the fish also swim up the edges of the water to populate farm dams. For those who haven’t been fortunate to have their dams populated naturally by this method, direct stocking with Firetail and Empire Gudgeons and Rainbows will keep the dams free of mosquitos and midges. It is best to avoid stocking with Spangled Perch (20cm) as they are very aggressive and eat all the smaller species. They also breed exceptionally rapidly, which leads to overstocking with a lot of stunted fish.

The best way to help maintain our beautiful watercourses is to ensure the margins of the creeks are well planted with trees that will shade the water. This will reduce the weed growth and ensure that mats of algae do not form because of the phosphorus levels plus the extra light. If horses and other livestock are kept, leave a substantial margin to the creek planted with shrubs and herbage that will take up the fertility from the horse manure before it gets washed into the creek.

We have a wonderful asset with our waterways which support an amazing amount of interesting wildlife from insects, frogs, birds and mammals. The efforts of the property owners and the work of the MCCG restoration groups are vital in keeping it this way.

 

With thanks to Ed Frazer for another excellent Bush Bites.

Across Gold Creek from my hide, where I have been monitoring a breeding Platypus in recent years, is a Sandpaper Fig. Its notable feature is that it is old, but apart from that it is just another tree arching over one of the two large ponds of the creek.

I have taken an interest in this tree because there are long periods of waiting between sightings of the platypus, but there are many similar trees overhanging the creek.

How it got to be growing just in this position could probably be because one of the figs from further upstream was washed down the creek and was deposited in a recess in this section of the creek many years ago.

I have no idea how old the tree is, but it has clearly seen better days as it has lost many branches and shows several signs of old age including severe termite attack.  It would certainly have been around in the first half of the 20^th century when this section of Gold Creek was the local swimming hole. It was probably around before the land was cleared and used as a dairy farm by the Dart brothers. I can imagine it existed when members of the Turrbal or Jagera aboriginal groups populated the area. Perhaps the aboriginal children snacked on its fruits before lollies were available from the Brookfield store.

Since the cattle went, Chinese Elms have invaded the cleared areas and the swimming hole is no longer used, but the creek banks have a good cover of Sandpaper Figs and Creek Lily Pillies and other natives, so this section of Gold Creek is in good condition and supports a wide range of wildlife.

The Sandpaper Fig has many decayed limbs, and one hole is the resting place of an elderly Northern Mountain Possum. He camps here during the day when he is visiting this part of his territory. The Sandpaper Fig is interconnected with other trees along the creek by several vines. When the possum wakes up in the evening, he climbs upwards and takes off on an aerial highway that covers much of the creek.

He is joined by many other inhabitants who also use this network. Young water dragons sleep along the thinner branches during the night where they are safe from cats and other predators.

If the Water Dragons sense danger, they just plop into the water and swim to safety.

 Many birds frequent the fig’s canopy. Lewin’s Honeyeaters are always present – not for nectar, but insects which form much of their diet. Whipbirds are also common, and the fig produces fruit for a range of fruit eaters including Pale-headed Rosellas, Figbirds, Satin Bowerbirds and Rose-crowned Fruit-doves. Brush Turkeys and Noisy Pittas feed on the figs that fall on the banks of the creek. Striated Pardalotes use the fig as a staging post as they excavate their many holes in the bank of the creek where they raise their young. One parent will wait impatiently in the tree with an insect in its beak while calling incessantly until the other parent leaves the hole and it is their turn to feed the hungry young.

Most of the figs fall into the water and there is always a team of Eel-tailed Catfish waiting below.

As well as fruit the Sandpaper Fig drops a considerable number of leaves throughout the year. These rot down in the water and start a food chain involving bacteria and fungi, which are eaten by worms and aquatic insects such as dragonfly, mayfly and midge larvae, which are then eaten by fish and platypus.

The creek is usually ankle deep in mulm derived from the leaves and fruit and the platypus’s bill with its electrified sensors is ideally adapted to sifting out the insects and worms contained in the debris.

When the creek floods the mulm is washed away and a new cycle develops where the whole process speeds up with the input of minerals and light. Floods undercut the banks developing suitable dens for the platypus and water rats. Here too, roots of the Sandpaper fig stabilise the bank. The underground extent of the fig is just as large as the aboveground branches and trunk and the fig produces two distinct types of roots. The structural roots support the trunk and branches and take up water. The fine roots collect the nutrients to feed the growth.

The trees along the creek are essential for the health of the creek and support an amazing amount of wildlife. Clearing to the edge of the creek destroys this habitat and leads to a breakdown of the ecology of our waterways. The work of the MCCG environmental restoration groups in revegetating our waterways is vital to maintaining Moggill and Gold Creeks in a condition that is as close to pristine as any waterway in Brisbane.

FOOTNOTE

The Sandpaper Fig was snapped off by the recent flood and washed downstream to the bridge at the junction of Adavale St. and Savages Rd. The Mountain Possum hole survived but it is very exposed, and it is doubtful it will be used again. A few young branches remain but the main trunk was severed about 2 metres above the ground. The entire root system survived and held the bank well so the old tree will rise again, but it will be many years before it plays its part in supporting the animals with food and the aerial highway above the creek. In the meantime, other young trees will take advantage of the extra light and take the old fig’s place in the canopy above Gold Creek.

Words and photos by Ed Frazer

Surviving the floods has been a test of our resilience in recent times, but how do the local wildlife manage the storms and the flooded creeks?

The answer is surprisingly well. Many species have very attuned senses and they are in many cases better forecasters than Bureau of Meteorology when it comes to detecting imminent storms. Most of our birds can easily detect drops in barometric pressure, wind changes, temperature drops, lightning and thunder miles away and either fly off to safer locations or take shelter in dense foliage or in nooks and crannies of tree trunks. Small birds are experts at positioning themselves close to the trunks on the leeward faces of the trees.

The biggest danger for birds is during nesting when eggs or young can get flooded. It pays to check out your area after a big storm. Several years ago I was out inspecting the damage from a particularly heavy rain period and I heard some tiny chirps at the base of an Iron bark tree and found a pair of small chicks with only pin feathers. I knew they were parrots but after feeding them for several days I was amazed to find they were Major Mitchell Cockatoos. I was aware of the parents who regularly visited us after they were expelled from a flock of 6 that lived up near the Gold Creek dam. After the chicks were fully grown they flew up into a Grey Ironbark  and one re-joined the parents and the other cried for three days until I climbed about 12 metres up the tree to retrieve it.  After another storm I found a Black Bittern, a seldom seen bird in Brisbane, resting after sheltering from a particularly bad storm.

Many of the larger birds just sit out in the rain and take advantage of the feast of worms flooded out to the surface. Generally, the birds manage the storms quite well.

A bedraggled but very satisfied Australian Magpie after feasting on worms brought to the surface by the flooding rain.

With the huge volumes of water flowing down Gold and Moggill Creeks during the recent flooding you might wonder if all the fish were washed down the Brisbane River into Moreton Bay. Fish are also adept at handling the conditions. The main defence of the Eel-tailed Catfish is to find deep spots in the creeks where the water flow is less strong. Other species move to the edges of the water where they find slower water behind obstructions such as clumps of refuse, large tree bases and side channels. It is well-known that the small mosquito fish, Gambusia, swims up the edges of the flow in floods and this is how they successfully populate farm dams where they were never intentionally introduced. Some natives such as Firetailed Gudgeons also use this method. Flooding can be a bountiful time for fish as fast water can dislodge aquatic insect larvae such as Dragonflies and Mayflies making them easy food for the waiting fish.

Fish are also highly streamlined and coated with mucus which reduces the friction and makes them highly capable of swimming against strong currents.

Frogs are very well adapted to flood periods, which actually stimulate their breeding as their  calling  during the recent rains will testify. The constant wet weather makes it easy for them to travel and some species make use of flooding conditions. The Great Barred and the Great Brown Brood-frogs lay eggs well away from creeks under stones or in clumps of grass and rely on flood water to wash their eggs into the waterways. Other species such as the Ornate Treefrogs and Ornate Burrowing Frogs lay their eggs in temporary ponds where there are fewer predators. These species develop very rapidly with the Ornate Treefrog taking only three weeks in the tadpole stage as they feed on the algae and micro-organisms that develop rapidly in the ephemeral ponds.

The Ornate Treefrog lays eggs in temporary water after heavy rain. They go through metamorphosis in 6 to 8 weeks.

For our two aquatic mammals, platypus and water rats, big floods can cause some problems. Both are highly intelligent animals and they also have some heightened senses and quickly adapt to changing conditions.

The Platypus have two types of dens. Breeding Den entrances usually are at normal water level and rise upwards and go back a metre or two. Fortunately the young were out by about the end on November so there would have been no losses of pugs during the recent flooding.

The Platypus have several other dens where they hole up during the daytime during the rest of the year. Along our part of Gold Creek there are lots of places where the banks are undercut from earlier floods and many go back a considerable distance and are well above normal water level. The Platypus use multiple dens along their range depending where they are feeding. During the recent flood most dens would have been underwater and the Platypus would have to move out. They are extremely strong swimmers and would have skirted around the edges of the flood and probably made temporary dens in the flotsam pushed up from the flood.

An undercut bank in Gold Creek which a Platypus has been using for several years. It goes back at least 1.5metres. The Platypus’ senses are so acute that it can detect movement at the lookout above.

The Water Rats are not as committed to needing an aquatic environment as the Platypus. They regularly raid our nursery buildings well away from the creek and steal goldfish and ornamental snails. They are very clever animals and would have had no difficulty in finding cover for their daytime sleeping quarters while the flood was raging. They would not have any problem keeping warm as they have one of the most dense waterproof furs of any animal.

A Grass Skipper butterfly sheltering from the rain

Butterflies are rather delicate creatures and small enough that a raindrop in comparison to their size would be like a 10-litre bucket of water hitting us. They have a number of defences, but foremost is simply perching on the undersides of a good strong leaf. Some shelter in nooks and crannies of trees and the common Evening Browns shelter under clumps of grass. Ladybirds also shelter on the undersides of leaves and some species congregate in large numbers under loose bark of Eucalyptus trees.

After the Flood.

Mostly our wildlife survive these periods quite well if they don’t coincide with their breeding season. But after the flooding there can be a period of where feed can be in short supply. Nectar and insect eating species can have problems, but unless it is just before winter it usually doesn’t take long before things get back to normal.

For seed eaters there can be a feast on the ground.

Fish in the creeks may have a shortage as the insect larvae live in the debris and mulm that will have been washed out. However, in a few weeks the build-up of mosquito and midge larvae will result in plenty. Without these periodical flooding events the creeks get overgrown and the water quality goes down so the cleanout and inflow of water from the land loaded with nutrients results in a bloom that starts a flush that benefits the environment and the animals living in our creeks. This recent event fortunately was during the warmer months so the recovery will be rapid.

Photos and  words by Ed Frazer.

 

 

Lacewings are a diverse and interesting group that are an important part of the insect fauna in the Moggill Creek catchment area.

They are equipped with highly effective “fangs” and are vicious predators of a wide range of insects including many pests.

The eggs are unusual in that the are usually laid in rows under leaves hanging from slender stalks.

Lacewing Eggs  Photo:Ed Frazer

The hatched larvae vary enormously. One group, the Ant Lions live in dry areas, such as under the eaves of a house, where they build an inverted cone in the soil with steep sides. Ants that fall into the cone struggle to get out and are captured and eaten by the Ant Lion, which lies concealed at the bottom of the cone.

Another group of species attach objects to their backs and move around on the ground or on the stems of plants, well camouflaged as they track down aphids and larvae of other insects.

Lacewing lava with camouflage  Photo: Ed Frazer

A primitive group of Lacewings that is now only found in Australasia is the Split-footed Lacewings. These relatively large sized lacewings are known outside this area only by fossil records. While some of their larvae adorn their backs with camouflage litter others live openly on the undersides of leaves, usually in the vicinity of creeks feeding on anything they can trap with their fearsome jaws. The larva look so different from their beautiful green winged adults it is hard to believe they can make such a transformation when they pupate and metamorphize into their winged stage.

Larva of a Green Spotted Lacewing – one of the Split-footed Lacewings  Photo:Ed Frazer

Adult Lacewings range in size from about 1cm to 5cm. All have in common translucent heavily veined wings. Most are highly predacious in both the larval and adult stages and have very efficient jaws. Little is published on the life history of this interesting group, which is well represented in this area.

Small lacewing about 1cm feeding on minute insects on a leaf of grass  Photo: Ed Frazer

Split-footed lacewing the size and appearance of a dragonfly  Photo: Ed Frazer

In the latest Bush Bites, Tim Spencer shares his recent experience with a Yellow-tailed Black Cockatoo.

Loving birds is one thing, but photographing them is a completely different matter. It can be endlessly frustrating but once in a while something unexpected occurs.

Several weeks ago I wandered up the back of my place near the end of Savages Road, camera and 300mm lens on my shoulder. I heard a close-by noise and looked to my left and there, not more than 3m away and at head height was a Yellow-tailed Black Cockatoo. This bird had an agenda and was in no way concerned about my close proximity. A tall but narrow Wattle tree was the focus of attention. Half the tree had been stripped of bark and wood exposing a cavity within.

Went back to get my wife Carolyn, “hey, you got to come and see this”  We spent about 20 minutes watching as the bird diligently removed large fragments of wood and bark, there was no way I would put a finger anywhere near that beak! I stayed on another 10 minutes, had trouble lining up under trees as I was a bit too close for the camera lens focus.

Anyway, as I said, Persistence pays off and the bird was finally rewarded for this with a fat, juicy, Witchetty Grub. After devouring the grub the bird flew off in answer to a mate. Looking at the tree and damage, it was clear the bird had extensive knowledge about getting such treats. The amount of damage and a similar place on the other side but lower down where the bird had initially tried led me to believe that at least an hour had been spent in securing the grub! Yum!

 

Words and Photographs by Tim Spencer