To: 'COG List' <>
Subject: Triller
From: Philip Veerman <>
Date: Wed, 16 Oct 2019 04:34:35 +0000

That may well be. I will add a little historical perspective here. Oh good that I see Mark’s good question after I typed this message and just add this sentence before sending.


The GBS started in July 1981. The early GBS records showed that the numbers observed were exceptionally high in year one (1981-82) (and somewhat high for a few of the other early years). Until (years later when) the data were compiled and available in The GBS Report, there was no way of seeing the trend. Now that it happened to be very high in year one produced a graph that suggested that the species was in strong decline from a high start. Thus a thought of a baseline. I think this contributed to its listing as “vulnerable”. This may not have been valid (at least on that basis), the comparison may only have been high that year. We don’t know what it was in prior years. I even think I heard whispers blaming The GBS report, but that did nothing more than show the data…… The GBS report text states these issues as below. I am not suggesting I know the answers but I suggest that, as with many migrants, prevalence locally can vary a lot from year to year and that the factors that cause this are very likely things occurring outside our area. So high numbers again this year? Believable and probably true. The blitz weekend should provide a very good pointer as the species inhabits areas that should get a lot of survey effort. And they are easy to find.




Note of course that “16 records” means that, it does not mean “16 observations”.


White-winged Triller Lalage sueurii

A summer migrant that inhabits woodland. It is not a suburban bird but passes through the city or stays on

the edges in suitable habitat. Almost absent in autumn and winter, most arrive in September then it rises to a

November peak and declines again quickly. The birds are quite vocal when they arrive. There is no sign of a

second peak as the birds go north again. Maybe they leave quietly or through another route. In Year 1 the

numbers were extraordinarily high and with 16 records, it was recorded at a high 28% of sites (compared with

the mean F% over all years of 8.33%). Birds stayed from start of September to end of December at some

sites. This included many pairs and larger groups. By contrast, there have only been nine records in the last

six years. Unfortunately we do not know whether Year 1 was a peak year or part of a downward trend that

has continued for this species since then.

Breeding records are in decline, all 10 records are from the first nine years. Apparently a compact breeding

period, activities at nest from early November to late December and dependent young from late November to

mid February.

Graphs on page: 102, Rank: 85, Breeding Rank: 44, A = 0.01394, F = 8.33%, W = 11.2, R = 0.829%,

G = 1.68.


From: Martin Butterfield [
Sent: Wednesday, 16 October, 2019 2:55 PM
To: Hawkins, Brian
Cc: COG List
Subject: Re: [canberrabirds] Triller


Certainly.  There seems to be one calling permanently in Glebe Park and another was in full voice by NLA on Monday.  Several at Isabella Pond the past two days and a pretty male at Gambles TSR this morning.



On Wed, 16 Oct 2019 at 13:54, Hawkins, Brian <> wrote:

Does it seem to anyone else that there are a lot more WW Trillers in Canberra at the moment that in previous springs?  In the last day I have heard them at Mawson, Curtin and Yarralumla.


-----Original Message-----
From: Martin <>
Sent: Sunday, October 13, 2019 5:33 PM
To: COG List <>
Subject: [canberrabirds] Triller

⚠ CAUTION: This email originated from an external sender. Verify the source before opening links or attachments. ⚠

I was very surprised to hear a White-winged Triller in full voice in Glebe Park this arvo.

Sent from my iPhone

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