That is a good, straightforward and useful honours project. Indeed my comment was influenced by my memory of the article “Birds, Berries and Bad Bushes”
CBN 11(3): 94-99 that Michael Mulvaney (1986) published in Canberra Bird Notes, that describes that study. This was during the time I was
CBN editor. Although I had forgotten who it was that wrote it….. Looking back now I also realise how awkward it was to publish stuff back then. As I recall our typist had to either switch type balls every time between changing fonts italic or normal
or type italic bits separately, and you can see it in the wonky lines………
Philip
From: Lia Battisson [
Sent: Wednesday, 29 May, 2019 10:17 PM
To: 'michael mulvaney'; 'Philip Veerman'
Cc: 'Rosemary Blemings'; 'COG Chat'
Subject: RE: [canberrabirds] Superb Parrots in the Hughes area
Very interesting discussion, thank you all for your contributions.
From: michael mulvaney <>
Sent: 29 May 2019 9:01 PM
To: Philip Veerman <>
Cc: Rosemary Blemings <>; COG Chat <>
Subject: Re: [canberrabirds] Superb Parrots in the Hughes area
For my Honors thesis many years ago I fed car injured rosellas and a king parrot many thousands of Cotoneaster and Pyracantha seeds - none passed through in a viable state - they are indeed seed destroyers rather than spreaders. Gangs Gangs
and Superbs are our friends when it comes to weeds - which is not the case for silvereyes or Currawongs. Preference by fruit eating birds for firethorn berries (which have smaller seeds) and preference by parrots for Cotoneaster (which has large seeds) was
why I proposed that Firethorns were at that time (1980) much more widespread in the bush than Cotoneasters despite Cotoneasters being much more commonly planted.
Cheers Michael Mulvaney
On 29 May 2019, at 8:15 pm, Philip Veerman <> wrote:
I have long been of the impression and think it correct, that parrots are primarily seed eaters. This was not my invention but I believe supported by good evidence.
On that basis, the seed is the food they are seeking, rather than the fruit, although they will consume fruit also. On that basis, parrots almost certainly digest all or most of the seed they eat, which thus is not passed through them. So parrots are likely
to be minimally if at all involved in seed dispersal. This is different from the situation of Silvereyes, Currawongs and others that spread
invasive species into the natural areas those being largely fruit (not seed) eaters, it appears do not destroy the viability of
seed and are dispersers. Therefore I do not easily or at all accept Rosemary’s last point. Of course the situation could be more involved and there may be variations between plants and between parrot species. If there is evidence that I am wrong in my main
point, I would like to be shown that I should abandon that idea.
From: Rosemary
Blemings
Sent: Wednesday, 29 May, 2019 7:12 PM
To: COG Chat
Cc: Ryu Callaway; Chris Davey; Sandra Henderson;
; m("gmail.com","helen.walker");">
;
Subject: Re: [canberrabirds] Superb Parrots in the Hughes area
Thank you all for sharing these Superb Parrot sightings.
As there was a photo and a mention of the Superbs eating Privet berries:
- do the birds’ digestive systems enhance or destroy the berries’ viability?
- Privets and Cotoneasters are the commonest berried invasive species in the ACT as numerous volunteer and professional landcarers
will attest.
- The ACT’s avian emblem photographically-specialises in eating Hawthorn berries. (Hawthorns are now rarer in suburban gardens than
the other two invasives.)
- Ironic that spectacular birds such as Superb Parrots and Gang - Gangs are helping Silvereyes, Currawongs and others spread invasive
species into the natural areas all species so desperately need!
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