Saturday, November 15, 2014

Our POZIBLE Crowdfunding Project: Nestboxes for Owls

With less than $1000 to raise at this moment, and 17 hours remaining to do it in, I'm hopeful. Check out and have a look.  http://www.pozible.com/project/186331

Though it is of course always possible to fall just before the finishing line. Keep your fingers crossed. Or pledge, if you haven't already and want to help us help owls.

Wild Barking Owl, D Pearce

It's definitely worth getting yourself onto the list of supporters. Once it becomes Brunswick Valley Landcare's Nestboxes for Owls project, there will still be updates. There'll be pics of the scenery ... we have that in spades. Pics of the nestboxes up in their trees. Internal shots showing the inhabitants.

We may have to wait a year before owls use a particular box. I heard of a box in someone's farm yard that first housed a possum brood, then a galah brood, finally a pair of barn owls. They had a great layer of duff brought in by the previous tenants.

Barn Owl at Currumbin Wildlife Sanctuary, R Hollands

Depending on the number of nestboxes we end up with and the number of owl habitats, we may install two boxes on one tree, one above the other. Dr Brendan Taylor, nestbox monitor, said in the owl talk we had a few weeks ago,that possums will opportunistically take the lower one, leaving the upper one for birds. It's something to experiment with.




Wednesday, November 12, 2014

Owls and Nestboxes

Troy O’Keefe, local raptor carer, and Dr Brendan Taylor, working in nest box monitoring, spoke at the Brunswick Valley Landcare sponsored Owl Event at the Mullumbimby Community Gardens on Saturday November 1.

Barking owl roosting in the daytime & keeping half an eye open for trouble,
photo sourced from free internet stock
Ten attendees made for a very informative afternoon, with everyone able to ask questions and have them answered in detail. And we learned wonderful detail about the lives of our native owls, and their care should they be found in an injured state.

The breeding up of mouse plagues cause barn owls to raise two nests per year of owlets. The young owls when first making their way in the world are the most vulnerable to being killed by cars. Perhaps their hunting skills haven’t developed yet to where they don’t need to scrounge by the side of the road. Perhaps the end of the mouse plague spells their doom, and they become part of nature’s natural attrition rates.

Our region is home to three species of masked owls: the barn owl which is also called the white owl, or sometimes the ghost owl; the masked owl; and the sooty owl which can be almost black. Sound is gathered in the disk, like in a satellite dish, and the owl’s ears underneath it are unusually large. Masked owls hunt in the pitch dark and can hear a mouse’s heartbeat from 500 metres.

An injured owl has two defences. First it’ll flip onto its back, facing the unlucky carer with its talons. Here’s where it is good to have two old towels in your car, says Troy, instead of the usual one for injured koalas. Throw the first towel over the talons and the owl will instinctively grip the towel. Drape the second towel over the owl, covering the face, and you can then pick it up without getting bitten. Put it in a cardboard box for transport to a caring situation.

Troy loves to get dead owls. He has a feather bank in his freezer. Using titanium shanks, and feathers saved from dead owls, he can repair a broken wing or tail well enough to last until the bird’s next moult.

The barking owl, the powerful owl and the boobook are our hawk owls, that use the early light of dusk and dawn to catch their prey by. There may be only eight breeding pairs of powerful owls remaining on the NSW north coast. Only the boobook isn’t a threatened species.

Monitoring programs may show only 30% of nest-boxes in use. Yet evidence around the boxes leads to the conclusion that up to 90% of nest-boxes may be being used through a year. Animals such as gliders may use up to nine dens per year as they move around their territory.

It’s all right and even a good idea to mount boxes one above the other. Possums will opportunistically take a lower box, leaving the higher one for owls and wood ducks, also a high nesting species. Owls may use a nest-hole for twelve weeks, but will come back to it yearly.

It takes a few years sometimes for a particular species to use a nest box. In the meantime others, possums, gliders, ducks and galahs have built up a good layer of duff. Many species import eucalyptus leaves as nesting material, thought to be disinfectant against bird parasites.

There are hundreds more things to learn. Hopefully while we are installing our nest-boxes, at present being made here and there, with the funds we are raising. $5145 with 3 days to go. Afterwards by monitoring, and enjoying the fledglings and possum young. Our fundraising page: http://www.pozible.com/project/186331


Tuesday, November 4, 2014

Book Review: Where Song Began

Where Song Began: Australia’s birds and how they changed the world by Tim Low, 2014, Viking.
Where Song Began is such a fascinating, enjoyable and richly detailed story that I haven’t been able to review the book in the conventional manner. I still have much reading to do and so instead will tell you some of the things that interested me.

Being swooped by birds has not been a common experience for me, barring the odd plover fly-by when crossing a football field on my daily walk. This year, in Brisbane, while I sat near the cafĂ© in the Botanical Gardens, a kookaburra egged on by a pair of noisy miners, took the last of my lunch from my fingers. The next day, while I again ate and drank, this time under cover at a student cafeteria, a pair of noisy miners flew in, grabbed the sugar that I don’t use from the table … you know, one of those little sachets … and proceeded to feed from the tube as if it was a flower.

In Where Song Began, I became engrossed in the reasons for our birds’ unusual behaviours. Tim Low explains that here many trees and plants are pollinated by birds. Nectar birds on other continents tend to be humming birds. Here we have a huge range of honey-eaters of all sizes and many parrots that live on nectar, not to forget mammals such as sugar-gliders and fruit bats. Trees in flower are defended by birds for the use of family groups. Noisy miners grow into tribes of up to 200 members. Fascinating stuff.

Australian birds accordingly are aggressive for the very good reason that many Australian trees have evolved an attractive high energy food that can last for days. Sixteen flowering banksia cones producing nectar for twenty days can constitute a honey eater’s territory that will need to be protected against others.

Not only are Australian birds aggressive against people whom they see as dangerous to their young, or their food source – the currawongs in my backyard almost took a piece out of me when I came dangerously close to the fruiting bangalow palm – they are also aggressive against other birds. We’ve all seen noisy miners chase off the competition as well as magpies taking on channel billed cuckoos dangerous to their eggs and nestlings.

Australian soils are by and large impoverished. How often have we been told not to add garden-strength fertilisers? Not to dump rich garden waste. The theory by Orians & Milewski (2007) goes that our trees cannot convert the carbohydrates they make into tissue or seed due to the lack of soil minerals. “The surplus sugar is fed to birds as nectar in return for pollination. Birds can thrive on this sugar as they eat insects as well to provide the missing nutrients.” (Low, p12)

I read about Ice Age survival. With no wind-blown seed, Australian trees did not move in the last period of extreme climate change and therefore are not expected to move in the present period of swift climate change. In the past, trees survived in small pockets, refugia, because their pollinators wandered the landscape searching for trees in flower. There’s a case there, says Tim Low, for concentrating our conservation efforts on birds and bats.

Due to my new interest in owls, I looked for them in this story. It turns out they are late arrivals on this continent, with a presence of only a few million years. Why then, I want to ask Tim Low. He makes the case that since Australia does not have a suite of large mammalian predators, birds have taken up those niches. So why owls so late in the piece? What were the predators before them?

Among the trees that can only spread by the dispersal of their fruit, another interesting resonance is the number of large-fruit fruiting trees that no longer have a dispersal agent. Eleven local trees including the Davidson Plum are now dispersed mainly by human actions. Together they apparently prove the once upon-a-time existence in this region of a dwarf cassowary. I’m looking forward to the time that they find that birds DNA in amber and we can have it revived Jurassic Park style.

The pied currawongs now taking over suburbia and surviving in towns over winter, gladly feed on privets, cotoneaster, camphor laurel, firethorn, hawthorn and holly. Come spring they are the main predators of small nestlings and eggs. Robins are vulnerable to extinction if not already threatened. Another reason for continuing to educate gardeners. Birds can be brought back from the brink if we replace exotic berry bushes.

These facts make up only some of the fount of knowledges in this amazing story, and not even the primary premise. I have to read the book again to take in that, but couldn’t wait to share it with you, and encourage you to beg borrow or buy Where Song Began. You won’t be disappointed.