I responded to John. I think John’s observation has relevance to a single flock of Pied Currawongs. As in, I see it as a question about behaviour, rather than
abundance. Yes I agree that large flocks of Pied Currawongs aren’t that unusual. However the question about behaviour is legitimate and may
relate to a disturbance of some kind, or them reacting to a predator (Jenny Bounds suggested recently a flying fox). John’s observation describes a specific behaviour that is not the usual thing you see of birds simply flying to a roost area.
I looked at the ABR and have no idea what the numbers given there mean. Or maybe I do but I question are they useful. They seem to record (at least for GBS)
the tally of adding all the numbers for all the weeks. Or the tally of all counts submitted by other means. Of course both are ludicrous bits of information, as especially for GBS, it multiple (repeat) counts all the observations of the same birds over successive
weeks, and it is totally dependent on the number of observer weeks. To demonstrate this, the figures would be about 7 times as much if the GBS was on a daily grid. For general results for a common bird it relates more to the number of surveys done than anything
else.
Also counting birds flying to or from a roost site is also highly influenced by the timing and observation situation and will obviously generate higher numbers
than what I think John was asking about.
Philip
From: Jack & Andrea Holland [
Sent: Friday, 26 April, 2019 8:50 AM
To: John Harris; chatline
Subject: Re: [canberrabirds] Currawongs
John, not sure if anyone has responded to you, but large flocks of Pied Currawongs aren’t that unusual. There was a group of 50-60 on Cooleman Ridge for a few weeks last winter, and I note that the 2017-2018 Annual
Bird Report notes a maximum flock size of 104 for that year. This was well below the 10 and 30 year averages of over 500. I expect some of these would be similar to the roost flights over my place in the 1980s, where over 200 were regularly counted in the
mornings as they flew over from their roost site at Narrabundah Hill/Mt Stromlo.
Sent: Thursday, April 25, 2019 3:50
PM
Subject: [canberrabirds] Currawongs
At least 60 maybe 100 Pied Currawong’s on the east side of Percival Hill. I have never seen such numbers and wonder if others have.
There is normally a winter roost of 10 or 12 on Percival Hill but these numbers were remarkable, flying high and returning to the trees, calling loudly and continually, perching mainly in the
highest branches of the eucalypts but some lower, chasing each other etc etc. Has anyone seen similar?
