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Many thanks for comments to my earlier
note concerning the Crimson Rosella count. Very interesting. Clearly we
have a long way to go before we understand what is going on.
Chris Davey: Many thanks for sharing the info. from
Dick Schodde on the different moulting times for the two sexes. I also did not
know this.
Harvey Perkins: It would seem we could well have
regional differences if your impression from Kambah reflects a more normal
breeding season for this species. In suburban Ainslie and in the Mt Ainslie/Mt
Majura Canberra Nature Park, I have only seen a few young. We also had none
at our bird feeder this season.
The birds I counted at the base of Mt Majura seem
to be largely coming out of the suburbs (Hackett, Watson).
Benjamin Whitworth: Yes, I have also
sometimes noted flocks of immature birds only, although I thought (but
I may be wrong) flocking may happen a bit later in the season. Where do the
birds go? Sometimes you don't see any 'green' birds for a long time, and
suddenly there appear 3 or 4 in the garden.
Bill Handke: The Mynah can rightly
be blamed for many things. But in this case I doubt that it explains poor
breeding success in Crimson Rosellas (assuming I was right in my original
assumption). In the central northern suburbs, the Starling
population crashed a few years ago and although Mynahs moved in,
numbers are still relatively low. This would mean currently less competition for
nesting sites compared to times when Starlings were common. (At the same time,
cutting of trees or heavy pruning, and the many house renovations may
increasingly be depriving birds of natural hollows and access to roof
space.)
I would agree that there is plenty of food for
Rosellas, but the drought may impact in subtle ways. For example, there may no
longer be the best mix of food items available, or the quality may have
declined.
Well, whatever the final story may be, it is
probably worth keeping on eye on this species for some time to come (Alistair
Smith will do this already! Thanks). The different plumages of old and young
birds give us a better chance of gaining a few more insights.
Michael Lenz
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