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Thursday, 14 February 2013

Goanna in the Roof!

Sometimes there are animals sharing the spaces we occupy most frequently and they are so cryptic, we may never see them.

This great photo was taken by mum fabulous mum who is becoming quite the wildlife photographer! I'd tried a few stints sitting patiently and waiting for this elusive lizard to emerge while visiting my parents' place, but with no luck. Yesterday mum went outside, saw the lizard, rushed in and managed to not only return with her (small point-and-shoot) camera but sneak incredibly close for this shot. So... what IS IT!!??

Well, this is a Black-headed Monitor, (Varanus tristis), a common but rarely seen arboreal (tree-dwelling) monitor. It is one of the most widespread of our goannas, occurring over most of Australia and varying quite a bit in colour across its range. The animals here in the Perth Hills appear almost entirely black, but if you look closely you can see the fine pattern of paler circles (called 'ocelli') over the back.

'Tristis' is a brilliant climber and spends much of its time ascending trees (what a life!), hiding in hollows and crevices in bark. It can also sqeeeeeeze into small spaces: I have watched one climbing upwards inside a hollow branch turn completely back on itself and start heading down, in a narrow space only 4cm wide! Since European settlement, tristis has also taken to living in rooves, hence this photo. The lizards are probably attracted here because of the complex structural environment of beams, cracks, nooks and crannies in which they can hide, which offer a safe refuge from predators. Gutters also provide a nice sunny place in which to bask!

Furthermore, many rooves contain rats and mice, a valuable food source, and the monitors probably find it quite easy to smell their way into a rat's nest and devour the babies. They also feed on frogs, birds' eggs and a variety of insects, including many which are garden pests. For this reason and the fact they help keep our rat and mice numbers down, they are a huge asset to your garden!

A problem arises when we want to get rid of rats and mice in our roof, and use poison to do so. Poisons are always something we should treat with caution but so often people don't waste any time in using them without thinking of the consequences. Animals like the Black-headed Monitor, and other vertebrates including owls, hawks, bandicoots and your very own dog or cat, will be killed via secondary poisoning if they find a dead or dying rat and take a bite. Strychnine, the most common chemical in rat poisons, kills the animal by causing muscular convulsions and eventually asphyxia, so its not the nicest way to die! But there is one poison, called Racumin by Bayer, which kills rats and mice without causing secondary poisoning. If you must use a poison, make sure you seek out some of this stuff (it's available in local hardware shops, just ask around), and do your bit to keep our local wildlife safe.

Tuesday, 5 February 2013

Blossum for the Possum

 What trees do you have in your backyard, or in your street? Are they fabulous Red-gums!?

The Marri tree or Red-gum (Corymbia calophylla) is a local native plant found only in the south-west of Western Australia. Growing over 30 metres tall, Marri is one of my most favourite climbing trees. Sometimes old individuals have limbs drooping right to the floor, like magic arms gracefully bending down to offer you a lift up. The one pictured above is about 20 metres high, has an ENORMOUSLY thick trunk at the base and is at least 200 years old!

The word ‘Marri’ is a Noongar word which means ‘blood,’ so called because of the thick red sap which leaks from the tree, forming glistening globs that light up in the afternoon sun like magic jewels. Local Aboriginal people used the sap for its medicinal properties and it was mixed with water and swallowed to help a sore tummy. I’ve also gargled a Marri mixture when I’ve had a sore throat, and although it tastes disgusting, it really helps ease the pain. Try painting Marri sap on your arm – it easily washes off with water so makes really good fake blood!

You might not think these big trees are related to the tiny flowers in your garden, but that’s exactly what they are: giant flowering plants. The flowering period for Marri is from about December to May, so right now we’re in the thick of things. You don’t need to look too hard to see the hundreds of fine yellow-white flowers covering the tree like a blanket of snow. Have you noticed the sweet, honey-like smell? In order to smell it we humans need to be quite close, but there are other noses which are able to detect it from far away.

Brushtail Possums (Trichosurus vulpecula) are nocturnal marsupials which emerge at night to forage on a variety of plant material, including Marri blossom. We are lucky to share our space with these native mammals, especially in the Perth Hills where our surrounding forest provides plenty of habitat. Listen out your window at night – can you hear the stems, leaves and fine parts of the eucalypt flowers dropping on your roof? Possums discard these as they carefully pull apart the flowers to reach the sweet nectar in the centre, often hanging from their thick, prehensile tails to reach drooping foliage.

Possums usually survive well in areas where tree canopies are connected, so they can climb through the branches without having to come to the ground. Otherwise they can get eaten by foxes, and, while you might not consider it, pet dogs too. Dogs smell out possums, chase them, and even if they do not physically attack, they cause severe shock which can lead to death. On the Swan Coastal Plain, many trees have been cut down so possums are not as common as in the hills. They can in some areas adapt to foraging on a variety of exotic trees, especially fruits like apricots, apples and nectarines, and they will also eat roses. But it's not just the food plants they need. Shelter is just as important, and possums need adequate den sites in which to sleep during the day. In natural situations these take the form of hollows in trees (which to be the right size for a possum take at least 150 years to form), and occasionally dead hollow logs on the ground. A common adaptation in modified environments is to live in the rooves of houses, which most often leads to a fate of eviction.

Do you lack possums in your area, and wonder why this is the case? It's probably because your neighbourhood has at least one of the following three features, which contrast directly with a possum's basic requirements:

  1. Fenced in backyards containing dogs.
  2. Few trees, or none with continuous canopies.
  3. Little or no tree hollows or suitable den sites.

  However, possums can still find homes in urban backyards if you manage your yard to meet these needs. Planting local native trees, keeping your dogs fenced in a separate part of your backyard (like my neighbour does), and learning to adapt your lifestyle so you can live WITH possums will all contribute. Now, you might well be reading this and thinking 'I live in a flat, how can I help?' Well, you can join a local Friends Group or take ownership of some bushland in your area. And if you have a few trees in your backyard, you can install nest boxes which possums will eventually learn to live in. Look who was seen emerging from the nest box in my backyard recently:

I'll finish this with a good reason to have possums around. Tonight I was getting dinner when a head poked out of the nest box shown above, just on dusk. I went outside and watched this amazing mammal emerge silently, then clinging to the tree trunk in expert fashion, literally run upwards into the canopy. After dinner I shone the torch outside and watched not one, but FOUR possums feeding on the blossoming Marri in our backyard. They effortlessly moved through the canopy, balancing their way along each limb before leaping with sheer skill to shift to the next tree. I was totally captivated and a feeling of awe and inspiration came over me. What an absolute privilege to share space with such amazingly skilled animals! Witnessing such things stimulates the human imagination and calms us from the busy lives we lead, helping our minds keep active and healthy. And possums are just one animal among the huge variety of other creatures that live in and depend on Marri trees for food and shelter. How lucky are we!?


Sunday, 3 February 2013

Birth of the Musk Duckling!

Isn't this one of the most ADORABLE creatures you can lay eyes on!? Today I was blessed with good luck when I went to check on our Musk Duck nest and found the eggs hatching. I recorded some footage of the first chick pipping out of it's egg, then left a miniature video camera recording to monitor what happened. When I returned 2 hours later, I was thrilled to find I'd captured the whole event on film!

You can see in the above picture that this ducking, only hours out if its egg, still has a clearly visible egg tooth at the end of its bill. This is a unique feature of all birds and is needed to crack through the shell, then is shed a few days after the young emerge.

The short film 'A Hatching Success' can be viewed below:
A Hatching Success from Simon Cherriman on Vimeo.