Satin BowerBirds - sexing? /& other notes

Subject: Satin BowerBirds - sexing? /& other notes
From: Judith L-A <>
Date: Wed, 3 Nov 2004 07:36:00 +1000
Yesterday (up at Mt Mee /Ocean View), while watching 'our' Satin Bowerbirds in the garden, I began to wonder how possible it is to sex the green birds by behaviour? Here is an example of what we see:
        On this occasion, four green birds were active in front of us. All had dark beaks. Usually this would only define them as 'either females or very young males'. (And one would then begin to wallow in, say, whether or not the throat is scalloped or spotted, whether or not the mantle is streaked, etc.) However, I observed the following--
        Two of the birds (1 & 2) were more 'flighty', nervous, than we're accustomed to seeing. The eyes of both were brown-blue. Of these two, one had a pale 'eye-ring' and both seemed a little pinkish around eyes and head. Occasionally, one or other of these two would take a break from feeding and perch quietly on a branch, with a fluffed-up 'nestling' look to it.
        These two were often in the company of a third dark-beaked green bird (3). This bird was steadier in its manner; did not flinch when closely overflown by M1 (our bower-holding mature male); and at least once that I observed, appeared to quickly feed one of the two birds (1 or 2), when it approached in a swift low movement across the grass.
        The fourth  dark-beaked green bird (4) was not foraging with the other three for fallen figs in the grass, at this time. A little further off than the first three, it was near the edge of the low shrub-canopy where the young males traditionally have their winter workshops. However, though clearly a very young bird, 4's posture was continuously tail-raised. And his performance of the 'dance' was excited in the extreme. Never have I seen any of these bowerbirds perform so wildly as to flip around with the beak as a ground-fulcrum as this bird did! It was 'overwrought', 'uncontrolled', frantic, but still clearly THE dance.
        So:  >From all these observations, can I deduce their sex behaviourally? -- To say, maybe, that bird number 3 is a female? (& possibly the mother of 1 &/or 2?) -- and that bird 4, though still dark-beaked & indecipherably green, is a male (& unusually precocious?)? -- and simply that birds 1 & 2 are 'infants', last year's brood perhaps? (& essentially 'sexless', yet?)
        ...Is it possible that long, close observations could eventually be extrapolated to produce some behavioural criteria for sexing green birds...?

(Please note also that on our place, while the male M1 uses violet-blue objects for bower decoration, the objects that are presented to the females by all males [or are used to practise presentation in workshopping] are light yellow, whenever these activities have been within my line-of-sight.)
        (Note too that a snakeskin has appeared as decoration in M1's bower -- first time for him, I believe.)


Judith L-A
S-E Qld
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