Re: FW: [canberrabirds] Cockatoos dropping rocks

[Martin Butterfield <>]

Back in the day, when I was living in Adelaide and fit enough to orienteer, one of the more risky course was a pine forest near Cape Jervis.  The trees were very tall (perhaps 30m)  and well endowed with very large cones: my guess was the cones were approaching 1Kg when green.  When Black-Cockatoos were feeding on the cones they would occasionally lose their grip and gravity would assist the cones to descend, landing with a pronunced 'thud'.   

I'm not sure of the physics of it, but am reasonably sure a cunning runner who was hit by a descending cone would not be well!  As far as I know this never happened but I was always happy to be out of earshot of the cockies and the thuds of falling cones.

Martin

Martin Butterfield

http://franmart.blogspot.com.au/

On 11 May 2018 at 09:32, Geoffrey Dabb <> wrote:

The story may have originated from the tendency of the SCC to drop quite heavy cedar cones.  Beneath a large nearby tree I have occasionally heard a heavy thump caused by a near miss from a cone dropped by a cocky taking flight.  Just now I gathered a selection of discarded cones which I weighed at around 70g.   However, those were dried cones.  When green they could be at least 200g.  Cockies taking off with cones carry them in the bill, typically with an insecure grip on the outer layer of a whole cone.  I do not believe they would be capable of holding a ‘rock’ larger than a golf ball, putting to one side any reason they might have for doing so.  Seasonal attacks on green cedar cones can be seen around the older suburbs of Canberra, I’m sure.  They can be carried for some distance by disturbed feeding birds.

 

 

.  

 

From: Charles Buer [
Sent: Thursday, 10 May 2018 10:56 PM
To: Graeme Clifton
Cc: Matthew Willis; CanberraBirds
Subject: Re: [canberrabirds] Cockatoos dropping rocks

 

When we lived in Kambah, several cockies were used to coming to our bird feeder. We were  late putting seed out one morning and Margaret was hanging clothes on the hills hoist. Two cockies were in the tree above her and plucking branches off and hoiking them toward her to get her attention. This went on for 10 minutes or so until she gave in and got the seed for the feeder.

Charles Buer

 

No fixed address, use if necessary:

 

38 Birchmans Grove

Wamboin, NSW 2620

 

Mobile: 04 3738 1464

 

Sent from my iPad

On 10 May 2018, at 21:41, Graeme Clifton <> wrote:

Hi Matthew,
Sounds like a “wind up” to me.

Graeme

Sent from my iPad

On 10 May 2018, at 9:14 pm, Matthew Willis <> wrote:

 

A strange question...

 

A friend of mine is moving into a new apartment in Gungahlin with a big balcony. The building design means it extends much further than those above.

 

She came home the other day to find a smashed tile and a shattered rock nearby. She assumed it was dropped (accidentally or not) from one of the balconies above and asked the strata manager to investigate. Their reply read in part:

 

"I have spoken to our facilities manager and he has said that it is surprisingly common for cockatoos to fly and drop rocks and that this has been the case with a few other complexes across Canberra".

 

Has anyone come across such behaviour among Canberran cockatoos?

 

Thank you!

 

Matthew

*******************************************************************************************************
This is the email announcement and discussion list of the Canberra Ornithologists Group.
Emails posted to the list that exceed 200 kB in size, including attachments, will be rejected.
All emails distributed via the list are archived at http://bioacoustics.cse.unsw.edu.au/archives/html/canberrabirds. It is a condition of list membership that you agree to your contributions being archived.
When subscribing or unsubscribing, please insert the word 'Subscribe' or 'Unsubscribe', as applicable, in the email's subject line.
List-Post: <m("canberrabirds.org.au","canberrabirds");" target="_blank">mailto:canberrabirds@canberrabirds.org.au>
List-Help: <m("canberrabirds.org.au","canberrabirds-help");" target="_blank">mailto:canberrabirds-help@canberrabirds.org.au>
List-Unsubscribe: <m("canberrabirds.org.au","canberrabirds-unsubscribe");" target="_blank">mailto:canberrabirds-au>
List-Subscribe: <m("canberrabirds.org.au","canberrabirds-subscribe");" target="_blank">mailto:canberrabirds->
List manager: David McDonald, email <m("canberrabirds.org.au","coglists-owner");" target="_blank">mailto:coglists-owner@canberrabirds.org.au>