I last saw the Bulbul at the Wilson Reserve on 7 January 2003, for what it's
worth.
Bill
-----Original Message-----
From: on behalf of Paul Dodd
Sent: Wed 5/7/2008 4:44 PM
To: ;
Subject: Local extinction?
You've made an interesting observation here, Jen. I suspect that with rarities
such as the OBP or the Mallee Emu-wren, there are enough people looking for
them at any given time that we would notice pretty well immediately if they
"disappeared". That's probably true for a number of other slightly less rare
species. But for a species such as the Bulbul where people may occasionally
look for it, it could be many years before we realised that a particular
population was extinct.
Which brings up another issue - when is a population deemed to be extinct? If
there are no sightings for ten years? (The opposite of the ten-year
self-sustaining population "rule") Longer, maybe? Presumably if the mean
life-expectancy of members of a species is greater than ten years, then we'd
want to use a figure of much more than this.
Apologies for reducing such a potentially emotive issue to mere statistics.
Paul Dodd
Docklands, Melbourne
-----Original Message-----
From:
On Behalf Of
Sent: Wednesday, 7 May 2008 1:50 PM
To:
Subject: Local extinction?
Hi all,
The discussion on ferals has got me thinking. One of the first birds on my life
list was the Red-whiskered Bulbul. When growing up near the Yarra they were
never common but could always be found in our street.
In recent years the only location I had for them was the boulevard in Ivanhoe,
and even then there were only one or two. From about 2000 we would go over at
least once a year to get them on the year list. In 2007 we could not find any,
nor again in 2008. It seems that the last of these "ferals" in Melbourne has
fallen off its perch - or had that perch chopped from beneath it?
The loss is certainly not a threat to the world population, and some may
applaud this loss, BUT; it has made me realize how easily a bird can become
locally extinct without anyone particularly realizing it. It also shows, to me
anyway, how important the B-A and DSE atlas's are and how important records
are. For example I have reported two mammal sightings to DSE this year, mainly
to find out what I had seen, and in both cases the sighting was from a location
not recorded before for the species. If we do not know were our birds and
mammals are we may not notice when their range changes.
Back to the Bulbuls, perhaps future field guides will now need to delete them
from the Melbourne area?
As an aside we are off this weekend to see the reported flocks of Flock
Bronzewing. The sight of 1000s of these birds in a flock seems somewhat iconic
to the outback and is something I have wanted to see since I first started bird
watching. I also relate it to the historic reports of the American Passenger
Pigeon. I do hope our Bronzewings never suffer the same fate.
Happy birding everyone
Jen
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