One the previous two days I spotted a Great Crested Grebe in breeding
plumage on Wallaga Lake in Beauty Point. What a fantastic bird! This
location is on the northern border of the Bega Valley Shire just south
of the Eurobodalla shire. (The border is in the lake, I believe.) By
road, Beauty Point is about 8km north of Bermagui.
For historical reasons, sightings from this spot are of interest to
the record keepers in both shires so I sent the info along. It sounds
like this species hasn't been spotted in the Bega Valley Shire since
2007 or in the Eurobodalla Shire since 2008. Based on a suggestion,
I'm posting a note here on Birding-Aus.
I didn't manage to find the bird again today but it's overcast, windy
and cold at the moment. The lake is large and complicated and there's
plenty of other good habitat nearby. Hopefully, I'll reacquire it and
can post again, if people are interested.
When my wife and I first spotted the bird we were pretty surprised -
we couldn't even remember seeing one in Australia before (I checked my
notes and we've seen them here - but not in NSW or the ACT.) Is there
anywhere in Australia that these birds can be seen reliably?
I was impressed by how long these birds can stay under water - I
didn't remember that detail. The bird disappears with virtually no
trace and seems to be able to stay down for a minute or more, although
I didn't time it.
I'm curious about this species preferred habitats in Australia. I've
seen grebe species around the world in fresh, brackish, and sea water
- but I though of Great Crested Grebes as preferring fresher water. It
seems that I'm wrong about this - but I want to include an observation
about Wallaga Lake. For those that don't know the area, this is a
tidally flushed lake so its exact composition and salinity changes a
lot over time. It was blocked more often than not (extensive silting
from decades of logging in the hills feeding the streams flowing into
the lake) but the entrance to the sea has been open for about two
years without interruption. The lake normally hosts good numbers of
Black Swans (hundreds), three kinds of cormorants, spoonbills, Silver
Gulls, Pied Oystercatchers, pelicans, and a range of other likely
candidates in lesser numbers (Red-capped and Hooded Plovers, Little
Terns, Caspian Terns, any other wader that passed through, etc.) Until
this year I had never seen any kind of grebe species on the lake. Not
once in the better part of 10 years - although I can easily find
Australasian Grebes in fresh water nearby. Starting about a month ago,
around two dozen Hoary-headed Grebes showed up. Neighbors have been
stopping to ask me about "those little ducks". I suspect that the
water composition has changed in some way (salinity? oxygen? algae?)
to make it attractive to these species.
Here's a slimmed down excerpt from the Bird Life fact sheet on the
Great Crested Grebe (link further below):
The species breeds on fresh or brackish waters with abundant emergent
and submerged vegetation, showing a preference for non-acidic
eutrophic [I think that this means "nutrient rich and oxygen poor"]
waterbodies with flat or sloping banks and muddy or sandy substrates,
usually 0.5-5 m deep and with large areas of open water. Suitable
habitats include small pools or lakes, backwaters of slow-flowing
rivers and artificial waterbodies (e.g. reservoirs, fish-ponds, gravel
pits and ornamental lakes). In Australia the species also utilizes
swamps, reservoirs, lagoons, salt-fields, estuaries and bays, and in
tropical Africa and New Zealand it may breed on montane, subalpine and
alpine lakes up to 3,000 m.
While on the subject, below are some references for this bird - better
details gratefully received.
I noticed some posts about Great Crested Grebes recently on the
Canberra birding list, including a link to the Canberra Ornithological
Group's atlas data:
A visual summary of the data on the COG database for Great Crested Grebe.
https://docs.google.com/open?id=0B7cBqe3MzqSXZjJEaVI4YjlBV0k
Two were spotted on Lake Tuggeranong on the 10th.
Can anyone offer some background on the Great Crested Grebe population
in Australia? I've had a look at the new atlas but it doesn't really
clarify things for me. From a bit of Googling, am I correct in
gathering that there are three (largely) non-overlapping supspecies
globally? One in Europe and North Asia cristatus), one in Africa
(infuscatus), and one here and in New Zealand (australis). That would
explain the huge bands of territory between here and Asia that the
bird doesn't reside in.
Bird Life Fact Sheet
http://www.birdlife.org/datazone/speciesfactsheet.php?id=3639
Geographic differentiation in the Australasian great crested grebe
Spoiler: They don't think that the NZ population is genetically
distinct from the Australian population.
http://www.doc.govt.nz/upload/documents/science-and-technical/DSIS34.pdf
A nice summary page with a few photos:
http://travelling-australia.info/InfsheetsP/Podiceps_cristatus.html
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