Interesting to see these topics getting some discussion on birding-aus.
I am as yet to be convinced about the OBP debate with windfarms. The
difference between wind turbines and lighthouses being that light is
continual but the turbine blades obviously rotate so there is a greatly
reduced chance of collision. to our knowledge, they also do not 'attract'
birds. The example of lighthouses raised by Martin O'Brien is by no means
restricted to Australia; there are examples all over the world. I find that
the levels of ambient lighting in Melbourne are pretty astounding
altogether. Cut-off lighting does not seem to be widely used. An obvious
example from the UK would be Felixstowe docks which for many years did not
have cut-off lighting. For years, the adjacent Languard Bird Observatory
used to have enormous catches of migrants but the levels plummeted when
cut-off lighting was introduced to Felixstowe. Although it is largely banned
now, lighting used to be used to draw in migrant birds for ringing purposes
elsewhere.
Another example of a potentially clandestine impact would be electromagnetic
radiation. Take Basslink for example. The impacts of this on marine mammals
and fish, including sharks and rays, is considered quite potentially
damaging. But what of the effects on migrant birds crossing the Bass Strait.
And this effect is not only confined to the cable. There are radar stations
and other microwave producing structures along our coastlines.
There is a fascinating paper by Wiltschko et al. on these effects on migrant
Tasmanian Silvereyes. Much in the style of the original bird migration
studies using caged birds in planetariums etc., the authors took spring
migrating Silvereyes and subjected them to a strong magnetic pulse. This
resulted in a significant deflection towards the east for 4 days and it took
10 days for birds to resume normal behaviour.
In terms of OBP conservation, I would regard ambient lighting as one of the
most likely problems that these birds face. It's not uncommon to have migran
ts around vessels in the Strait at night. Unfortunately I wasn't on board
during the OBP migration or I would have been keeping my eyes peeled. But
during the summer there are a lot of brightly lit squid boats out there as
well.
I am not saying that electromagnetics would also be a great problem but
siting a microwave emitting structure on the edge of an estuary or headland
could have similar effects to a lighthouse and far more difficult to prove.
If anyone wants to see a copy of the above paper by the way, I have it as a
PDF and can forward.
All the best,
Simon.
_____________________________________________
Simon Mustoe - Director
AES Applied Ecology Solutions Pty Ltd.
59 Joan Avenue
Ferntree Gully
Melbourne
Victoria 3156
AUSTRALIA
Telephone 03 9762 2616
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Website www.onthe.net.au/ecologysolutions
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