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18 Oct 2022

Lachlan Swamp, the animals that live alongside us

Nestled in the middle of Centennial Parklands is one of the hidden gems of Sydney – Lachlan Swamp. A place where clear, clean water bubbles up from the ground and supports a community of plants and animals living in amazing abundance right under our noses. Let’s explore together and meet some of the animals that call it home.

What makes Lachlan Swamp a special place?

This natural spring has been a resource for people and animals in the Sydney area for thousands of years and was an essential source of fresh drinking water for the establishing city. It exists because of the unique geology of this part of Sydney. Deep, sandy soil allows rain to penetrate easily, filling up the porous sandstone layers beneath and throughout the Botany Sands with water. Like a giant sponge these rocks then release that water gradually. It bubbles to the surface where conditions allow and feeds the wetlands that still stretch from Centennial Parklands through suburbs like Eastlakes down to Botany Bay.
Lachlan Swamp sits on the headwaters of this system and stays wet throughout the most protracted droughts, supporting the swamp forest and marsh surrounding the spring.
The green open spaces of Centennial Parklands are an essential part of the system, allowing rain to refresh and replenish the groundwater, like a green island in an urban area..

Swamp paperbarks

The swamp paperbarks are the dominant species in the swamp forest. They were deliberately planted in the late 1800s and replaced a lower and more open swampy heath environment. This species can easily handle waterlogged soils and has thrived, with generation after generation of new seedlings filling in gaps in the canopy as old trees die. Various other species have also colonised the area, including bats, wing ferns and soft bracken, palms and sedges and paperbark figs, which have created a mid storey that feels almost like a rainforest.

The animals of Lachlan Swamp

The dense vegetation and moist microclimate make Lachlan Swamp an important haven for many species of animals, including insects, frogs and lizards, many species of birds both large and small and even large mammals. For many of these species the swamp is a breeding refuge in the middle of a bustling city, where they can rest safe from disturbance. Keep reading to learn more about our most important and interesting species, some of which are an active part of the ecosystem.

If you pause and watch at any of the pools in and around Lachlan Swamp you can’t help but see a wide range of different dragonfly species. These efficient aerial predators are amongst the most successful hunters in the world. They have existed for over 325 million years and ancestral species had wingspans of 75cm.
Dragonflies spend the early years of their lifespan underwater, where they stalk ponds and streams, hunting other invertebrates and even tadpoles and small fish. They live underwater for up to 5 years, but once they are flying above the water as adults, they only live for a couple of weeks. Once they are flying, dragonflies are extremely active, hunting small insects like mosquitos, aggressively defending a waterside territory and engaging in beautiful mating flights, before laying eggs and dying.
Around the world dragonflies are in decline, largely because of habitat destruction as wetlands are drained and developed. Lachlan Swamp and the ponds of Centennial Parklands are critical remnant habitats for this beautiful and important insect.

Did you know? Dragonflies are successful in over 95% of hunts and can eat up to 100 mosquitos every day. Imagine how many mosquitos there would be without dragonflies. 
A characteristic feature of swamps are the huge, dense webs of Golden Orb Weaver Spiders (Nephila plumipes). These large, harmless spiders make permanent webs, unlike other orb weaving spiders who make and remake their web every evening.
Golden Orb Weavers like to live in colonies, with their webs forming dense tangles of very strong silk. This tangled mass helps protect them from predators like birds. The webs are so strong that in addition to their usual prey of moths, cicadas and other insects, small birds and bats can even get trapped and the spiders will also feed on them!
In some years Golden Orb Weaver numbers peak, and the colonies can cover whole trees and fill up all the spaces between the trunks and branches on the edge of the swamp forest.
The large spiders you can see are actually females. Themales are tiny and hide around the edges of the webs hoping to find a meal and a mate while avoiding being eaten.
Did you know? If you look very carefully you might see tiny shining silver balls on the webs of Golden Orb Weaver Spiders. These are Quicksilver Spiders which share the web, steal some of the spider’s prey and help keep the whole area clean.
The long finned eel (Anguilla reinhardtii) is an iconic feature of Centennial Parklands’ waterways. You might have seen one cruising along just under the surface searching for food. They are a type of freshwater fish and grow to over a metre in length. They hunt for fish, invertebrates and even young birds, ambushing them and engulfing them with their large mouths.
The eels spend much of their lives in the ponds, streams and lakes, even nosing their way right into the centre of the swamp. Their lifecycle is fascinating, and the eels will leave the swamp, travel down the linked wetlands to Botany Bay, before entering saltwater and swimming thousands of kilometres to New Caledonia. They breed in the deep ocean and then the adults will die. The baby eels hatch and over months travel back to Australia before returning to fresh water and making their way upstream and back into the swamps and ponds of the park.
Did you know? Long finned eels are a critical component of the park ecosystem, keeping the invasive carp numbers down by eating young fish.
A secretive and quiet resident of the swamp is the bluetongue lizard (Tiliqua scincoides). They are a species of large skink which lives in the undergrowth, sheltering under logs and in dense vegetation. They will come out to bask in sunny clearings among the ferns, warming themselves up in the morning. In winter they will curl up to sleep for the coldest months of the year.
Bluetongues eat insects and in particular, love snails. There are more of them around than you think and they will often occupy backyards and snack on catfood.
Bluetongues aren’t a fast lizard, and because they live on the ground they’re particularly vulnerable to dogs. Their only defence is to open their mouth and hiss, showing their blue tongue. This is why it’s so important for there to be areas where dogs aren’t allowed within the parklands and why dogs should be leashed where possible. Keep your eyes open for these beautiful lizards on your morning walk.
Did you know? Bluetongues give birth to up to 19 live young, rather than laying eggs.
A characteristic bird of Centennial Parklands is the fearless Magpie Lark (Grallina cyanoleuca). Often mistaken for their larger namesakes, the Magpie Lark pecks around for insects and other invertebrates in the lawns and around the banks and beaches of the ponds and other wetlands. They won’t hesitate to take on larger birds and can often be seen flying at birds of prey like goshawks and ravens.
The Magpie Lark is also called the Mudlark. They construct beautiful round nests by carrying wet mud into the trees and moulding it together. If you disturb their nest however, they might just swoop you.
Did you know? Magpie Larks are so territorial and brave, they can sometimes be seen having a fight with their own reflection in a car side mirror.
One of the real success stories of the swamp is the family of tawny frogmouths (Podargus strigoides). These nocturnal birds nest in the paperbarks, raising two and sometimes three chicks year after year. The chicks snuggle together on the branches, staying very still and perfectly camouflaged against the bark of the paperbark trees.
Frogmouths come out at dawn and dusk to hunt for moths and small animals, swallowing them whole with their huge mouths.If you are in the park at night, you might hear their deep, booming call echoing around. Look out for them along the edges of the swamp, where they can be frequently seen, but you need to keep your eyes peeled, because they look just like a branch or piece of loose bark.
Did you know? Tawny frogmouths aren’t owls, they belong to the nightjar family. Unlike owls, tawny frogmouths lack the huge feet, strong claws and massive eyes of true owls.
The kookaburras (Dacelo novaeguineae) of Centennial Parklands greet every morning and evening with their characteristic laughing calls. These calls signal to other families of kookaburras that this territory is taken, so rack off!
Kookaburras are opportunistic carnivores, taking anything that will fit in their beaks, even a sausage or two from a picnic or BBQ. In the park they’ve even been seen grabbing rats from the long grass before whacking them against a tree and swallowing them whole.
The kookaburras take advantage of the mature paperbarks in the swamp to breed. These large trees have hollows and even termite nests high in the branches, where kookaburras can make safe, cosy nests for their young. Mature trees like this are critical habitat for many hollow dwelling species and are so important in the urban environment.
Did you know? Kookaburras live in family groups, with uncles, cousins and older brothers and sisters helping to raise the young.
A raucous and cheeky resident of Centennial Parklands is the Sulphur Crested Cockatoo (Cacatua galerita). These large birds are incredibly intelligent and inquisitive and can tackle almost any problem, including opening bins and raiding the contents.
They need mature trees with hollows to breed and so can be seen entering and exiting the large paperbarks alongside the swamp. If you listen carefully you can sometimes hear the screeching of hungry babies.
Sulphur Crested Cockatoos can sometimes get too familiar with people, and can become a problem stealing food. You can help to keep these beautiful birds wild by avoiding feeding them around the park.
Did you know? Sulphur Crested Cockatoos can live for over 50 years and teach their babies all the tricks they have learnt in their long lives.
One of several mammals to use the swamp, brushtailed possums (Trichosurus vulpecula) are one of nature’s real success stories. They have colonised parks, backyards and roofs all over the urban environment.
These robust, opportunistic marsupials will take advantage of any resources that they come across while foraging at night. They will eat leaves, fruit and flowers, but also won’t hesitate to grab unattended eggs or even baby birds from nests.
In the swamp, they occupy hollow branches, but brushtails have also been quick to take advantage of the nest boxes the park’s management have placed around the park. If you are lucky and look up at one of the many nest boxes, you might see a furry bottom poking out, or even the cute face of an inquisitive baby.
Did you know? Part of the brushtails success is how quickly they can breed. A brushtail can have a baby every year and can start breeding at only 12 months.
The most obvious animal using the swamp is the camp of grey headed flying foxes (Pteropus poliocephalus). These large bats have a wingspan of over a metre and are Australia’s largest species of flying fox.
In the peak of their breeding season there can be over 80,000 flying foxes using the swamp. They fly out from Centennial Parklands every evening in search of fruit and nectar and return at dawn.
The bats from Lachlan Swamp may travel thousands of kilometres away, up and down the east coast of Australia. Flying foxes are a critical part of the ecosystem, pollinating gum trees across large areas and helping to distribute fruit seeds. It’s the bats who have been changing the nature of the swamp, by dropping fig seeds underneath their daytime roots in their poo.
You can see the bats using the trees in and around Lachlan Swamp. Take the time to watch them scratching, cleaning themselves, bickering and flying from branch to branch. If you do, you might notice one paying just as much attention to you. The bats are easily disturbed, which is why it’s so important that a quiet place like this exists for them to shelter, right in the heart of Sydney.
Did you know? Bats drink by flying low over the ponds and dipping their chest fur into the water. They then return to a roost and lick the water from their tummies.
Sitting at the very top of the Lachlan Swamp food web is the powerful owl (Ninox strenua). Australia’s largest owl, the powerful owl has a wingspan of over one metre and is easily capable of taking a possum, flying fox or large bird.
A true owl, the powerful owls that live in the parklands fly out over a large territory each night, hunting for careless creatures. They also breed in the parklands and can frequently be seen roosting in large trees and among the paperbarks. They try to keep a low profile in the daytime, because smaller birds will chase and attack them at roost, particularly noisy miners.
Powerful owls have become very rare, largely because of habitat destruction and fragmentation. However, there is a reasonable population maintaining an existence in Sydney, taking advantage of the thriving populations of possums and even the occasional cat.
Did you know? The powerful owl is the only Australian owl that hoots. The rest whistle, bark, screech and scream, anything but hoot!
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