An exceptional
year?
?certainly a
very interesting year! Just a few comments to the questions raised by Geoffrey.
For up to 10
years the local bird scene has been shaped by local and distant drought. We had
influxes of species normally found more to the West of us (such as White-browed
Woodswallow, Masked Woodswallow, higher numbers of White-winged Triller, Rufous
and Brown Songlark), and we have seen declines in some of our local breeding
birds, at least breeding success has often been poor. With the rains since late
2009 things have changed markedly. Importantly, conditions inland are now very
good. This has meant that there was no need for inland species to move East to
find suitable conditions for breeding. Hence, no White-browed and Masked
Woodswallow have been recorded in 2010 in our area, and to judge by sites I
visit, many Dusky Woodswallows have also left their former breeding areas here,
and no doubt have moved westward, further I have not recorded this species this
autumn over my GBS site while at the same time last year they passed through
often.
White-winged Triller and both species of Songlark were present in
quite small numbers during the last breeding season: most birds had no need to
come eastwards, however, sites that have those species present probably present
optimal habitat for them.
We had notable influxes of Stubble Quail in summer, and it seems both
species of Pardalote and Grey Fantail had very good breeding success to judge by
high numbers recorded everywhere this late summer/autumn. Most pleasing were
more sightings of Speckled Warblers this year during woodland surveys than in
previous years. And numbers of Diamond Firetails have also increased. No doubt
there are many other similar examples.
The rains in early 2010 triggered late breeding not just in
waterbirds, but also in a number of woodland species, most notably in
Thornbills. It seems that we may not see the same success this autumn. However,
some species, especially the Red Wattlebird, had an extended breeding season
(although I still think that a very wet 2010 spring often resulted in failed
first broods for this species; when I raised this once on the chat line, I had
both confirmation and statements to the contrary, so the impact may have been
patchy), and the Koel made good use of these late broods and a notable number of
late Koel fledglings were reported. This is quite intriguing. Are late host
broods more vulnerable to parasitism? (Perhaps adult hosts have to spend already
more time foraging than in spring/summer, hence nest attendance may be lower,
giving the Koel female more opportunities to deposit an egg?)
In the 2010/11 breeding season Noisy Miners have bred from early
spring well into autumn at all sites I have visited. In 2009/10 late broods were
only recorded from one population.
The widespread good rains had another amazing impact ? this time on
waterbirds. At urban and farmland water bodies, Australian Grebes and Wood Ducks
had a good and extended breeding season, with the latest breeding record for the
latter at the ANU from Robin Hide only the other day. Although both Lake George and Lake Bathurst partially filled (I am always
astonished how much more it has to rain before the lakes would properly fill;
both lakes have still a very long way to go: right now they are shrinking
again), this was not matched by numbers nor species composition of waterbirds.
Shortly after the initial partial flooding, good numbers of birds were recorded,
but soon most waterbirds moved inland with only relatively small numbers of
ducks and swans staying behind.
Apart from one
record of a Golden Plover by Dan Mantle, we had no records of any northern
hemisphere waders at those lakes for the last wader season (matching stories of
much lower wader numbers than usual being reported from key wader sites in
southern Australia). However, Australian waders have done well locally. Banded
Lapwings were recorded in good numbers, Black-winged Stilts have bred, and
Masked Lapwings formed larger flocks at both lakes.
Certainly a
fascinating time to watch birds and to follow what ever may unfold in our local
(and further afield) bird fauna. More than ever we need many, many records from
COG members documenting the changes and events, so that we can answer questions
such as whether or not a given year is exceptional or not.
Michael Lenz
Thank
you Martin, another informative graphic. When this year is analysed we
shall see the height of the W14 bar, but shall we ever be certain that a taller
bar represents an exceptional year. I would be interested to know whether
such a careful observer as Michael has any feeling that this year is
exceptional.
From: martin
butterfield [
Sent: Sunday, 10 April 2011
12:11 PM
To: Michael and Janette Lenz
Cc: chat
line
Subject: Re: [canberrabirds] Late breeding
Last friday was in GBS week
14. See attached in support of these being late records.
Martin
On Sun, Apr 10, 2011 at 11:02 AM, Michael and Janette Lenz
<>
wrote:
On Friday,
8. April, at the ANU a pair of Red Wattlebirds with a fully grown but still
begging young. Parents fed it repeatedly.
On the same
day in Civic a pair of Galahs feeding a young that looked as if it had left
the nest hollow only very recently.
