Sunday, 1 May 2016

Satin Bowerbirds

We have been fortunate to have a resident male Satin Bowerbird (Ptilonorhynchus(1) violaceus violaceus), including a bower, the male’s courtship display arena, continuously in our garden for about 10 years now.

Mature male Satin Bowerbird at bower.
Over the 10 years there have been at least six bowers that we know of, each constructed and decorated in a separate location with only one bower in the garden at a time. So it seems only one dominant male at a time is in charge of our garden.

As the males only reach the fully blue mature stage at age 7 and probably only live on average to about age 10 or 11 years, we have no doubt had a number of dominant blue males over the 10 years.

Each bower is dismantled as the new bower is constructed and the precious blue objects are moved to the new location.

Male bower birds are great thieves so the blue objects are continually changing at a bower as some items are stolen and new ones turn up - some of these stolen and some newly found. The objects include blue plastics of various origins, however blue bottle tops and straws are common and Crimson Rosella blue tail feathers are also common. A few yellow objects are included, often flowers, but sometimes we have found Sulphur-crested Cockatoo crest feathers at bowers in our garden.

This is the last bower before the one featured in this post. It has now been completely removed including blue objects.

The number of blue objects at the new bower is less than are seen in the photo above of the old bower so I am assuming some have been taken/stolen by other males.

The blue objects match the colour of the mature male’s plumage, though, depending on the amount and angle of the light, the plumage can vary from blue to black. The blue objects also match the vivid blue eyes of the females and immature males. The mature fully blue males have lilac coloured eyes (see photos).

While the activity at the bower is at a peak during the breeding season the bower is maintained throughout the year. The bower in this post was moved to this location over the past couple of weeks and is still being refined with new sticks added and sticks in place adjusted and painted. Even though it is autumn and the breeding season is over there is still plenty of display activity at the bower as the photos in this post show.

I was surprised to observe an immature male at the bower busily adding and adjusting sticks and painting the inside of the bower. The immature male also displayed and danced around the bower with blue objects held in its bill while another immature male looked on. The mature blue male was not present.

Immature male Satin Bowerbird. Note the green throat and breast with fine white spots and streaks. Also note the dark grey bill is just starting to turn a light colour at the tip indicating this male is about 3 to 4 years old.
The immature male spent 15 minutes or so adding and adjusting sticks at the bower.
This stick looks to be too short and crooked for the bower walls?
The bird was busy moving in and out of the bower.
A brief pause from bower work for a scratch.
The green birds are very attractive. This photo has not been cropped - I was very close, concealed in a chair hide using only a 300mm focal length lens.
The immature male took a break from bower work to put on a performance with a piece of blue plastic.

The display involves jumps and wing and tail movements while making various calls and buzzing sounds. Another immature male watched on.
The under tail feathers are very attractive – I am not sure what purpose such attractive feathers in this location serve given the females selecting mates are looking at all blue males?
A little later the blue plastic was discarded and a dry brown faecal pellet, or perhaps it is an insect larva case, was taken up and the display continued.
The display included a variety of moves including hops, side jumps and sudden wing movements.
The display continued.

In an observation session a couple of hours later when the adult blue male was present, two immature males were also at the bower. One of the immature males stood motionless inside the bower, as a female would, while the mature male commanded the display area and put on a performance with dance, a variety of calls and blue objects held in its bill.

The magnificent mature blue male arrived at the bower and the immature males adopted a subservient stance.
Note the lilac coloured eyes of the mature male, the creamy white bill and bill feathers.
This immature male appeared to adopt the role of a female at the bower in the mature male’s presence?
The immature male stood in the bower while the mature male moved about the display arena.
The mature male appeared larger than the immature males?

It would seem that young males practise bower construction at a mature male’s bower and also learn to display in preparation for the day when they reach maturity and build their own bower. The mature male in command of the bower, the owner, seemed to tolerate the presence of the immature males. I suspect this may not be the case during the breeding season when receptive females are visiting bowers.

(1)  From Fraser and Gray, Australian Bird Names - A Complete Guide.
Ptilonorhynchus from Greek means feather-bill.

The Satin Bowerbird and other species of this genus have a small patch of feathers extending from the forehead down over the root of the bill which gives the head and bill when viewed from some angles a rather unique shape – see photos.

Australia is fortunate to have 8 species of bowerbirds with 5 species in the Ptilonorhynchus genus. This list of Bowerbird species is copied from the BirdLife Australia working list:

Tooth-billed Bowerbird
Scenopoeetes dentirostris
Golden Bowerbird
Amblyornis newtonianus
Regent Bowerbird
Sericulus chrysocephalus
Satin Bowerbird
Ptilonorhynchus violaceus
Wet Tropics Satin Bowerbird
Ptilonorhynchus violaceus minor
Southern Satin Bowerbird
Ptilonorhynchus violaceus violaceus
Spotted Bowerbird
Ptilonorhynchus maculatus
Western Bowerbird
Ptilonorhynchus guttatus
North-west Cape Western Bowerbird
Ptilonorhynchus guttatus carteri
Inland Western Bowerbird
Ptilonorhynchus guttatus guttata
Great Bowerbird
Ptilonorhynchus nuchalis
Western Great Bowerbird
Ptilonorhynchus nuchalis nuchalis
Eastern Great Bowerbird
Ptilonorhynchus nuchalis orientalis
Fawn-breasted Bowerbird
Ptilonorhynchus cerviniventris

A post featuring the Western Bowerbird can be found here:

For more information about Satin Bowerbirds the following sites are well worth a look:

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