Wednesday, May 26, 2010

Priorities.....Yellow-tailed Black Cockatoo

I'm sure we all have a set of unwritten priorities when it comes to everyday life. So I'm also sure
that you would do the same thing as I did yesterday morning, in similar circumstances.
I was alerted by my visiting granddaughter Caitlyn, in her usual dramatic way, that a terrible catastrophe was taking place in the toilet. "Water's going everywhere grandpa, come quickly". Something was not well with the cistern, and water was spraying everywhere, including over me, and I soon found myself standing in a few millimetres of an ever widening pool of water, clean I hasten to add! I stopped the flow, but as I walked back through the kitchen to put on some old (and dry) clothes before fixing the problem, I glanced out of the window and down the garden. High in the angophora near the bottom of the garden, I could see a solitary large bird, unmistakably a Yellow-tailed Black Cockatoo.
They visit on occasions to feed on the Banksia integrifolia flowers and seeds, but this was the first visit of the year. Any thought of fixing the cistern or cleaning up, quickly disappeared, as I grabbed a camera and headed off down the garden. Unfortunately, the bird had flown. So thinking that was that, I headed back up the garden, but on nearing the house, I heard the unmistakable "kee-ow" scream of their contact call coming from the other side of a banksia spinulosa close to the house. Frustratingly, I couldn't even see the bird, let alone photograph it--foiled again. Eventually it flew back down the garden onto to one of the "integrifolias", finally giving me my photo opp., images shown. As I closed on the cockatoo at top right, I realised it was not alone in the banksia. as a head popped up on the far side, this time a male, pictured at left, and a third bird called from nearby, so they were most likely a family group. After 15 or so minutes, I heard an approaching flock of their fellows, about 18 in all, and "my group" soon joined them. all flying off to the east.
But it wasn't quite over yet. As I climbed the steps to the backdoor, the local flock of 40 or more Galahs, flew over screeching and obviously agitated, usually a sign of a predator about. But the object of their concern was a passing Pelican, fairly uncommon over my garden, flying high to who knows where.
So finally back to the cleanup, but feeling a whole lot more contented than I had a short while ago.

Friday, May 21, 2010

European Wasps and Birds

A recent story in the local paper, The Mercury, caught my attention, and told of losses being sustained by Tamar area grape growers. This time they weren't aiming their ire at birds, such as the Silvereye, but at the European Wasp. (Most vineyards are now netted). Wasps were apparently accidentally introduced to Tasmania around 1959, possibly from New Zealand, and they are now frequently encountered around much of the state. Unlike bees, they are able to sting multiple times and, speaking from personal experience, it's much more painful! The growers complaint was that they are losing up to 30% of their crop to wasps (eating fruit) and they wanted a public campaign to combat them.
My thoughts about the story related to several species of our birds that actually regularly include this pest in their diet, including Noisy Miners, Yellow Wattlebirds, Grey Shrike-thrush and the ubiquitous Silver Gull, but I suspect there are several others. The miners and wattlebirds almost certainly don't target them, but encounter them when both are attracted to flowering
eucalypts. Shrike-thrushes and gulls certainly do, as I recount below.
While birding in the Meehan Range, I came across a pool of water that had collected in a wheel rut and flushed a shrike-thrush from the water's edge. Cursing that I had missed a photo opp. by my lack of vigilance, I was surprised when it quickly returned to the poolside. Over the next several minutes I photographed it on the ground and in the nearby scrub, and despite repeatedly flushing it, it was always drawn back to the pool, but didn't appear to drink. Later, looking more closely at the pool I noted that there was a procession of wasps visiting the edge of the water, presumably to drink. It was then that the penny dropped, the shrike-thrush wasn't drinking but had found a great source of 'easy' food--the wasps.
I had noted and blogged a previous occasion that I had witnessed Silver Gulls targeting wasps, and a few days ago I took the accompanying images of a similar event, this time on Bellerive waterfront. I suspect that it's a regular occurrence. Several gulls lined up, some few metres apart, on the river's edge, facing towards the sun, probably to silhouette the prey. Individual wasps were flying from the shore across the water. The gulls would spot them and give chase as the wasps climbed ever higher. To catch them, the gulls had to use all their flying ability, but I never saw them miss. They would usually descend back to the rocks to eat them, but I couldn't determine whether they removed the sting before swallowing. I'd estimate that they were catching maybe 20 or 30 an hour, so it's probably not going to make too much of a dent in wasp numbers, but every little helps.
From all this a few questions arise. Where are the wasps going to (they're heading off across the Derwent River), or for that matter where are they all coming from, as there was a fairly constant procession of them? Why do the gulls bother with them as they would appear to have very little nutritional value?