spectacular gathering of corellas (not local!) - and channel-billed cuckoo in Wanniassa yesterday

[martin butterfield <>]

Having now re-read that tome - OK just the bit referring to the Slender-billed Corella, but I will get to the rest of it soon - I'd suggest both positions could be said to be supported by the material quoted there.  

In earlier times there was a natural population along the Murrumbidgee and Lachlan Rivers which disappeared due to changes in grazing patterns.  So one could regard that as being part of the 'natural range' of the species.  My comment about spread along the rivers may be a regaining of this traditional country.  

I hadn't realised how extreme the trapping of this species had been, and clearly escapes from and releases by the pet traders could certainly account for the concentration of observations around Sydney and Canberra (the parrot fanciers in the latter township generally seem rather light on their security measures).  

Martin

On Sat, Dec 19, 2009 at 4:45 PM, Geoffrey Dabb <> wrote:

Aha, Martin, a question of one’s perspectives perhaps.  I would have thought it was tempting to attribute extensions due to escapes and introductions to natural causes.

 

Joe Forshaw, a silent reader of this chatline, says he agrees broadly with my position on the Long-billed, the true correlation being with human settlement,  and we should look at Australian Parrots Third Edition

 

From: martin butterfield [
Sent: Saturday, 19 December 2009 10:42 AM
To: Geoffrey Dabb
Cc: Cog line
Subject: Re: [canberrabirds] spectacular gathering of corellas (not local!) - and channel-billed cuckoo in Wanniassa yesterday

 

Geoffrey
It is always tempting to attribute range extensions to escapes and introductions. 

Looking at the attached  LB Corella map from birdata (at I think10 minute level rather than the one degree cells of the Atlasses) there appears to be a rather high correlation between reports of outlier LB Corella reports (other than Sinny metro area) and the watercourses of the Murray Darling system.  Possibly that is a coincidence reflecting the likelihood of towns being on the rivers (or birders being on the rivers) but it does suggest to me that the birds might have spread themselves up the system from Balranald(ish).

Martin

On Sat, Dec 19, 2009 at 10:03 AM, Geoffrey Dabb <> wrote:

Interesting about the corellas, Sandra.  Numbers might be unusual, but I’d suggest they are still in their ‘normal’ range.  In the below adaptations of the atlas maps I’ve marked Deniliquin with a green star.  Even in 77-81 that was on the edge but within the natural extension.   The great spread further afield in 98-02 has been attributed to releases and escapes, and I think that accounts for the birds in Canberra.  By contrast the map for the Little Corella would show a continuous extension.  I think that is reinforced by the large numbers that turn up here periodically.  Therefore if we were suddenly to get a hundred Long-bills I would say the resident introductions had been augmented by an advance party from the riverina.  Another indication would be to watch carefully and see if they show a preference for Australian Rules, western Victoria and the riverina having strong traditional associations with that particular form of boot-ball.     

 

 

 

 

 

 

 

 

 

From: sandra henderson [
Sent: Friday, 18 December 2009 9:19 PM
To: Cog line
Subject: [canberrabirds] spectacular gathering of corellas (not local!) - and channel-billed cuckoo in Wanniassa yesterday

 

I'm spending the night in Deniliquin, at my favourite motel by the river.  For the past hour there has been a huge flock of long-billed corellas settling down for the night in the adjacent tall eucs.  The person in the unit 2 doors up estimates there are 5,000 in the flock.  Every now and again they all take flight together, calling loudly, circle a few times then back into the trees - I'm guessing some trees have literally hundreds of birds in them - all within 50 metres of my room - the noise is deafening and the sight is amazing. now that its almost completely dark I suppose they'll soon decide its time to sleep.

 

sandra henderson