28 April, 2012

The shepherd's companion

In the latter part of 2011 I made a few forays up the Barwon to the somewhat grandiosely named Mt. Brandon Peninsula. The results of my travels appeared in some of my previous blog posts. In particular, I spent some time photographing a nest belonging to a pair of Willie Wagtails.
Willie Wagtail and its nest, November, 2011
Yesterday, I headed back to Baum's Weir and the peninsula to see what was new. Everything was much as it had been before with the exception of a few dropped branches and a couple of non-native trees which were well into the swing of autumn. I did see several European Goldfinches past Baum's Weir and up on top of the peninsula as well as a flock of Flame Robins. This was the first time I'd seen either on the river.
I also went back to investigate the nest belonging to the Willie Wagtails. What a difference a few months can make. When I last visited the nest in November, the Willie Wagtail breeding season was well under way. It generally lasts from August to February and can involve the rearing of several broods of chicks.
Willie Wagtail in its nest, November, 2011
At that time, the female was always in the nest when I arrived and as I mentioned previously, she and her mate were typically aggressive in defending their territory both against myself and on one occasion, against an unfortunate Crested Shrike-tit which happened to venture onto their branch. I have also seen a Willie Wagtail take on a kingfisher and I believe they are quite happy to argue the point with even larger birds, including kookaburras and Wedge-tailed Eagles.
Perhaps because of their gregarious behaviour and chattering calls, the folklore of indigenous cultures across Australia tends to describe Willie Wagtails as the bearers of bad news. They are recognised as intelligent but are thought to tell-tales and steal the secrets of humans, according to some tribes, informing the recently departed if their living relatives speak ill of them. I have not been able to discover whether the local Wathaurong tribes have cultural links to the Willie Wagtail, however they cannot have been unaware of these vociferous little creatures in their landscape. They may even have raided their nests for eggs as they are often located well within human reach.
As is clear from the above photos, the nest is a cup shape composed of grass, bark and other fibrous bits and pieces, all bound together with cobwebs. The inside of the nest is lined with hair, fur and soft grasses. No-one seems keen to tell me what the spiders think of having their webs commandeered by the Willie Wagtails, but then, it is also quite possible that the spiders themselves have become dinner and are in no position to complain.
This time when I arrived, there was no sign of the birds and the nest was clearly in a state of disuse, except - somewhat ironically perhaps - by a spider or two who seemed to be taking their revenge.
Willie Wagtail nest April, 2012
Looking at the nest in November and now, it seems there were some additions made prior to the departure of the birds and the arrival of the spiders. The large twig still with seed pods attached is a more recent addition, as is what appears to be a piece of fishing line. Hair is also evident. It would be interesting to know where the birds sourced their building materials as there are not a lot of houses and their domestic animals in the immediate vicinity nor are there herd animals to provide these fibres.
It is from their habit of closely shadowing sheep and cattle or even riding on their backs - presumably to catch the insects they stir up in their wake - that Willie Wagtails are known as the Shepherd's Companion. Presumably they also take the opportunity to pinch a hair or two at the same time.
 I also noticed another interesting detail during yesterday's walk.  In November, I saw a Brush Cuckoo in the same tree as the nest and also saw Fan-tailed Cuckoos nearby. Now that the Willie Wagtails are no longer breeding, I neither saw nor heard any sign of cuckoos.
Brush Cuckoo in the vicinity of the Willie Wagtail's nest November, 2011
This is probably no coincidence as I discover that various species of cuckoo, including these two, will attempt to place their eggs in the Willie Wagtail's nest. The wagtails however, often recognise the impostor and remove it from the nest.
When summer and the nesting season end, the cuckoos - presumably realising the gig is up - depart for more northerly climes. The Willie Wagtails by contrast, hang around until it is time to start the whole process again.
As Willie Wagtails generally pair for life and are known to reuse nests, or to recycle old materials in building a new one, I will be keeping an eye out to see which - if either - happens with this nest and the birds who built it.

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