Hi all,
Last year on B-A I posted some observations about Welcome Swallows feeding
on insect larvae captured from *below* the surface of a pool outside the
Western Lagoons gate at the Western Treatment Plant (Werribee). Since then
I was asked to write the observation up for publication in a journal. For
various reasons this did not happen and I decided to publish a version of
it on my blog instead.
I then found a photo in the book *Where to See Birds in Victoria*, edited
by Tim Dolby (2009). On page 109 there is a photo taken by Glenn Ehmke that
shows the same behaviour. Glenn took this photo and others at Anderson’s
Inlet in July 2007 so the sub-surface feeding appears to have been
occurring in Victoria for many years.
I cannot find written reference to sub-surface prey feeding in anything I
have read on the *hirundinidae *family. There is, however, frequent
reference to *hirundinidae* feeding “over” water and maybe the authors were
just not being precise in their wording and or observations. It is possible
that all swallows are already known to feed on sub-surface prey but I
cannot find the behaviour explicitly stated.
Interestingly, according to HANZAB Vol 7, Welcome Swallows are migratory
with most Victorian birds moving north in April and May. Some Tasmanian
birds also move north, leaving Tasmania in April on their way to wintering
grounds in Victoria, which they then leave to return to Tasmania, beginning
in September. As both feeding events reported above occurred in July in
coastal Victoria the birds involved were either migrants from Tasmania or
some local birds that did not migrate, or a combination of both. As I have
not seen sub-surface feeding at WTP other than in July, and Glenn’s
sighting was also in July, could it be that sub-surface feeding is a habit
learned exclusively by Tasmanian birds and brought to their Victorian
wintering grounds? Or is July the only month in which suitable larvae hatch
in coastal Victoria? These are questions I cannot answer, and are ones that
will require more research by someone else.
It would be interested to hear if anyone has similar sightings this year,
or in the past, especially from Tasmania or NSW.
And if anyone is interested in the full article, with photos from Glenn and
myself, it is on my blog at the link below.
cheers
--
Jenny
http://jenniferspryausbirding.blogspot.com.au/
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