White-headed Pigeon’s status in Melbourne VIC

For the past 2 months or so a pair of White-headed Pigeons have been
recorded (with good pics) in Brighton, Melbourne, about 9km from the
CBD.

These are extraordinary sightings of the species in terms of location
and time of year, and I’d be very interested to have thoughts about
whether or not the birds could have come from aviaries. 

There has been no advertisement about lost birds on the web, including
Gumtree, that I could find.  But then our Barbary Doves were almost
certainly dumped from aviaries.

As to their being wild birds, I have in mind another species that
thrives on fruit trees introduced into Melbourne.  A female Koel was
recorded in warmer months about 16km from the CBD between 1986 and
1992 (at least).  That was well before the species became regular
(and breeding??) in Melbourne.  And then there are the Channel-billed
Cuckoos….

As I said, I’m most interested in thoughts – and data.

Michael Norris