Last week I wrote about the Variegated Fairy-wren as being Sydney’s “other wren”, the wren that it was “other” to being the more common Superb Fairy-wren.
When I heard that there might be more Variegated Fairy-wrens at north Coogee beach, I went there to have a look. Instead, I saw several Superb Fairy-wrens (Malurus cyaneus), starting with this male in his breeding plumage:
The others with him included another male, but this one was in non-breeding (eclipse) plumage.
Here’s a second view of the eclipse male, showing the blue tail feathers of this otherwise brown bird:
Another in the group was this female. She looks similar to the eclipse male, but has much less blue in her tail. Also, the area behind her beak and around her eye is an orange-brown colour, in contrast to the darker ‘lore’ of the eclipse male.
I left the wrens to look for other birds on the hill away from the beach. When I returned, the wrens had followed part of the way, close to the cliff-top fence. They were either perched on the low shrubs just outside the fence or hopping about on the ground nearby as they foraged for insects.
At one point, a female was sitting on one of the cliff-top shrubs:
At the same time, this Red Wattlebird, ten times her size, was feeding in a tree thirty metres from the cliff edge.
The wattlebird was in an aggressive mood, because it suddenly flew across the path at the wren. Fortunately, the wren saw it coming and ducked into the shelter of her shrub. (No photo, alas, as I wasn’t expecting this development!)
After that, peace descended once more. I took this last photo of the breeding male before heading home.
Back home later, I was able to look more carefully at my close-up images, and particularly at the unusual texture of the electric-blue plumage on a breeding male. It looks quite different from most feathers. Typically, a conventional feather has a central shaft or rachis, with a series of branches, or barbs. These barbs carry smaller branches called barbules, which in turn have minute hooks or barbicels for cross-attachment to the next barb.
These barbicels can be seen in the next photo, which is a composite of part of a lorikeet wing feather. The upper half shows the central black rachis, with the green barbs branching off. The lower half shows part of three barbs with the dark barbules branching off them. You can see how the barbules have a kink or bend in their middle, so that each row of barbules overlaps (or underlaps) the adjacent row to give more complete cover. Although you can’t really see the individual hooks or barbicels on the barbules, you can see by their furry appearance how they hold the barbs together.
Now compare this conventional lorikeet feather with the very different-looking blue feathers above and below the eye of our little male Superb Fairy-wren. The Fairy-wren’s feathers look very different - the whole feather structure has been flattened and fused into a series of long slender ‘scales’.
These flattened and twisted surfaces contribute to the iridescence of the blue plumage, and the colouring of the feathers also strongly reflects ultraviolet light. As fairy-wrens can see into the ultraviolet, the blue areas may appear even more striking to other fairy-wrens than they do to us.
I was also intrigued by the effect of the blue dusting on the male’s feathers below its blue-black bib. These feathers are structured more like conventional down or contour-feathers, and the dusting on them makes it seem like the bird has brushed against a freshly painted blue surface.
Superb Fairy-wrens live in small family groups with up to three to five birds of either sex. They are both socially monogamous and sexually promiscuous; they pair for life, but neither sex subscribes to sexual fidelity. Indeed Tim Low notes in Where Song Began that the highest levels of female infidelity recorded in birds are amongst Australian magpies (82%) and Superb Fairy-wrens. Perhaps because of this, all members of a family group will care for the group’s nestlings.
There are six subspecies of Superb Fairy-wren spread in a wide arc across south-east Australia from southern Queensland to South Australia and Tasmania.
I have lots of photos of these little birds – more than enough for another post!