yet another unexpected visitor

[meryl joyce <>]

Hello Everyone

I am new to the chatline and have been learning a great deal as a result of joining COG so thanks everyone.

I thought I would add something about bower birds who have been active in my garden in Campbell for the last few years.  Around this time last year an immature bird built a bower in my garden by the back gate.  It was a reasonable size when, at the same time this year, he was joined by a satin bird and they both worked on the bower, sometimes separately and sometimes at the same time.  Last Tuesday morning the satin bird demolished the bower and has since been seen disappearing over the gate with the blue decorations; most are already gone.  The green bird is still visiting the spot occasionally to move the bower sticks around but is not showing signs of rebuilding - yet.   

Meryl

On Mon, Aug 1, 2011 at 2:49 PM, Margaret Leggoe <> wrote:

Here is a closer look at the bill.

 

 

From: Geoffrey Dabb [mailto:m("iinet.net.au","gdabb");" target="_blank">]
Sent: Monday, 1 August 2011 2:01 PM

To:

Subject: RE: [canberrabirds] yet another unexpected visitor

 

More important than what it is, for information purposes, is my suggested approach (put forward for discussion).

 

First, adopt a common terminology.  Are we going to use ‘juvenile’ for any pre-mature bird, or, as I suggest, reserve the term for true juvenile (first plumage) birds and use eg ‘ímmature’ for birds from second plumage and before maturity.

 

Secondly, get the most informative image.  Is the below the best available?

 

Thirdly, look for signs that the bird is a true juvenile (first plumage) bird.  The below is evidently not in that category.

 

Fourthly, examine the bill for signs of yellowing.  (Not entirely clear in the below.)

 

If the bill is entirely black, the bird could be a 2/3 year bird of either sex or a female between 2 years up to and including maturity.

 

If the bill has signs of yellowing it is a male from 4 years to short of maturity.

 

Information about relevant behaviour or help from someone with expertise on plumage differences might be able to advance the matter further.

 

By the way, I sent my earlier message to Danny Rogers who added the comment: 

 

“ I would incidentally be surprised if males were completely consistent in the age at which plumage and bare part changes occur - in other species of bird in which long delayed maturity occurs there usually turns out to be some variation - in part probably driven by social and territory status, but perhaps with lots of other interacting causes too.”

 

 

 

Margaret Leggoe