White Cedar tree and the caterpillar attack

Tree trunk covered with hairy caterpillarsOur urban ecology provides a rich tapestry of interdependencies and sometimes these relationships aren’t immediatly apparent.

The tree Melia azedarach (White Cedar, Cape Lilac) is a lovely tree. In Australia, it has the distinction of being one of the few that are deciduous. This is important for our home. It provides very welcome summer shade but lets in light throughout winter. It looks wonderful in flower and growing right next to the house it is visually important.

However, it has a flaw. It is attacked by one caterpillar species Leptocneria reducta. The caterpillar assembles a population often in the hundreds and they eat the leaves of the tree until there are no more.

caterpillar species Leptocneria reducta

Counts of moths collected under ultra-violet light from a local study suggest that they have two generations a year. I wouldn’t be surprised if it’s more. Often I find the trunk carpeted by the caterpillars, the ground beneath the tree is full of their droppings. Of course, this raises the question, what do you do?

Leaves of the tree showing caterpillar damageThere are no real predators. Apparently Tawny Frogmouths (I heard one a couple of nights ago) will eat them. We have watched the caterpillars completely denude our tree. At which point they crawl off in search another. It has to be a Melia azedarach, this caterpillar is a specialist species. When they devour our tree, they crawl into the house, behind curtains, everywhere.

Our solution is to fight them. Unfortunately, we have had a bottle of pyrethrum spray permanently parked next to the tree. I don’t like spraying, I don’t like pyrethrum and I worry about the food chain and the effect on other species. Our tree has Birds Nest ferns, Elk horns and orchid species growing in and on the tree, lots of habitat. We have lovely skinks and millipedes that also inhabit the tree and there is a chance that they will get sprayed. All in all, it’s a dilemma for us and a minus for a tree which is particularly nice.

However, there is a silver lining. In our urban setting, the birds that reside here are aggressive and dominate, new birds are a rarity. So when something new comes around, it sticks out. Last winter I had noticed a smallish shy bird come in to the garden. It would be gone before I could figure out what it was or what it was doing. After a while, I noticed it would take some food from around the ‘Cedar’ and noticed it was taking caterpillars. I finally managed to get one reasonable photograph of it. It is a Fan-tailed Cuckoo which ‘enjoys hairy-caterpillars in its diet’. Our urban ecology throws up fascinating examples of winners and losers and the caterpillar, a pest species, becomes an important bird attracting species.

Fan-tailed Cuckoo

So, now that it is late summer, I am going to leave the caterpillars that I photographed yesterday alone. Hopefully they’ll provide an abundance of food for the Fan-tailed Cuckoo and some more opportunities to observe this bird.

There is a great site for information on this and other Australian caterpillars http://lepidoptera.butterflyhouse.com.au/lyma/reducta.html

I am a big fan of Birds in Backyards website http://www.birdsinbackyards.net/species/Cacomantis-flabelliformis

Information about the tree can be found at http://www.anbg.gov.au/gnp/interns-2008/melia-azedarach.html which notes that Melia azedarach can be a weedy species. I would agree! I am constantly pulling young seedlings up.

Fowlers Gap

Emu-7095I have had the good fortune to be part of a research project at the University of New South Wales’ 40,000 hectare research facility, Fowlers Gap.

It is vast. It is in arid country, 100 kilometres north of Broken Hill. An incredible place, it encompasses a hilly range, the same one that Broken Hill is a part of, ephemeral Eucalypt dominated creeks and grass or copper bush dominated plains. David Keith, in his excellent book ‘Ocean Shores to Desert Dunes’ (More information on the book) describes two ecological communities that are present here. Gibber Chenopod Shrublands in the hills and Aeolian Chenopod Shrublands on the plains.

Grassland plain at sunrise

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The plains are highly variable, sometimes Mitchell Grass dominated (pictured above), sometimes Maireana (Bluebush) and other times a mix. But, they are surprisingly diverse and it appears a healthy ecosytem supporting an array of wildlife. The Marieana, a Chenopod, has a fruit with wings ideally adapted for wind dispersal. I think the species shown is Maireana sedifolia.

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Maireana bush

The hills are harsher. Feral goats compete with the Euro kangaroo and other wildlife so that it appears in places over grazed and hostile.

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Shoal Bay – God’s country

Zenith Beach and Shoal Bay.
Zenith Beach and Shoal Bay.

I don’t know from where the expression ‘God’s country’ is derived but it seems an appropriate one for such an extraordinary place. It isn’t the built up part of Shoal Bay, that isn’t particularly nice nor particularly bad, but it is the surrounds.

The built area sits fringed by Tomaree National Park. Tomaree has these fantastic, windswept, heath covered hills atop igneous foundations or huge sand dunes covered with littoral rainforest. Between these hills are pristine beaches, Zenith, Wreck and Box, remote enough that even in the Christmas holidays they are perfectly peaceful and often deserted. On the opposite side to the coastal beaches in the photo above is the estuary of Nelson’s Bay.

The photographs are from our recent week away and a few days in spring. Most days we walked to Wreck Beach.

I love Australian plant families. They’re iconic. I love the genus Banksia, its family Proteaceae.

In the sheltered woodland behind coast, I thought the flowering species above was Banksia aemula which are a lot like Banksia serrata, B. aemula has a narrower leaf and they are often squat, technically they are separated into their respective species by the length of the stigma. The Banksia flower is actually a collection of hundreds of flowers, each with the potential to form an incredibly well armoured seed. These seeds are ready for the long wait and the possibility of one day being burnt, opening and falling to the ground in a nutrient enriched patch, courtesy of the fire, just right for germination.

The B. aemula doesn’t persist on the coastal side. There resides B. integrifolia, B. oblongifolia and B. spinulosa growing in the harsh environment.

Allocasuarina distyla dominated the slope closest the beach or at least that part that the track traversed. Big hills either side, so who knows what else dominated. The weather could change quickly producing the briefest moments of fantastic light.

Beachside Acacia longolia var sophorae and a little herb in flower – Cakile edentula (Sea Rocket) a native of north America.

The birds produced interest, noise and movement. Curious insects also.

But it was the sea and the time with family amongst this special environment that produced this feeling, fleeting as it was of bounty.

Mother-in-law and daughter
My mother-in-law and her daughter; my wife.

A fortune of sun, perhaps not heaven sent, but with beguiling beauty that really requires a catch phrase like God’s country to convey my joy in being there.

Sunrise from Tomaree Headland
Sunrise from Tomaree Headland