Friday, April 27, 2007

Feeding Egrets

No sooner do I extol the virtues of a Tasmanian Autumn than Murphy's Law kicks in and we get a week of heavy overcast and very still, weather. On the face of it, still conditions should be good for birding, but I know from my days as a bird bander, such conditions seem to reduce the movement of birds considerably.
The upshot of the conditions was that they
effectively grounded me too, as they were not very conducive for photography either. So this morning, with conditions slightly improving, I set of in search of Cattle Egrets.
These egrets are fairly common in Tasmania during the cooler
months, but in the South of the state the flocks are generally smaller than those in the North and North West, often only numbering in single figures. I get the impression that the numbers in the South have declined somewhat, possibly as a result of the drought conditions on the Mainland. I drove up the eastern shore of the River Derwent, noting a few Cattle Egrets in paddocks between Bridgewater and New Norfolk. On the northern outskirts of New Norfolk, in an irrigated paddock next to the main road, I came across a group of three feeding. This spot usually has one of the larger flocks, often numbering up to 20 birds, but today I could only find three. I spent half an hour or so observing and photographing them. Although this is a dairy property, the egrets usually prefer to feed in paddocks that have been set aside for future use and sporting relatively long grass, rather than among the cattle. I was interested to know what they were feeding on, and for the most part, it appeared probably that they were catching insects, but I did photograph one with an earthworm (middle shot), which surprised me. On returning, I looked up this egret's diet, which, in Australia as I guessed, was recorded as primarily grasshoppers, crickets, spiders, fish and frogs. I did find a South African source that mentioned earthworms as a major part of their diet during the Winter months, so it's probable that in suitable conditions, earthworms are important here too.
On the drive back, I called in briefly to Gould's Lagoon, and noted the 'usual' Great Egret there. Perhaps more noteworthy was that there were several Clamorous Reed Warblers still present, some calling. It's generally thought that they leave Tasmania in March.

3 comments:

John & Shirley Tongue said...

Hi Alan,
I've always thought it odd that Cattle Egrets migrate TO Tassie for the cooler months. It seems to be a kind of 'reverse migration'. We haven't seen the large flocks in the Northwest yet, though we did see 3 or 4 on a farm dam at North Motton on ANZAC day - the first half-way decent birding we've done since we got here - though seen quite a lot from the houseyard, including regular flocks of up to 6 or 8 Rainbow Lorikeets!

BirdingTas said...

Hi John,
Glad to see you've moved in safely, with a whole new area to explore. The flocks in the NW and North seem to favour very specific areas. The largest flocks I've seen have been around Smithton and Sheffield, with others in the West Tamar area. It seems that , like them or loathe them, Rainbow Lorikeets are here to stay. Saw one at Gould's Lagoon.

John Tongue said...

mmmmm,
I fear for many of our hollow-nesting species!