Sorry that I can't give a reference, but I recall an article (Emu?
Wingspan?) some years ago that reported a threshold size for viable
breeding colonies: I think that once the colony falls below 6 birds
they cannot maintain their population. I'm not sure whether this
study was about GCB or White-browed, or all babblers, but it doesn't
suggest a promising future for them if there numbers are getting this
low.
Russell Woodford
Birding-Aus List Owner
Geelong Victoria Australia
http://www.birding-aus.org
On 03/08/2007, at 6:32 AM, Greg wrote:
Speaking of Grey-crowned Babblers there is a general consensus
amongst birdos in the Clarence Valley, north-coast NSW, that the
average flock size of this species has declined over the past 20
years or so. It is based on anecdotal information only so I was
wondering if it appears to be the case in other areas. Flocks of 2
to 5 are more common now than larger flocks. It may be related to
the carrying capacity of disturbed habitats.
Greg Clancy
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