Advice needed for cleaning up this recording

["Peter Shute" pshute2]

Those of you who also subscribe to birding-aus will already heave seen Tom =
Tarrant's request for help with identifying the bird chattering in the back=
ground of this recording:
http://www.aviceda.org/audio/?p=3D208

The problem is that the call is distant and masked by frog and insect calls=
. Can anyone suggest techniques for cleaning it up to make the call clearer=
?

I tried high pass (>4000Hz) in Audacity, but it didn't clean it up enough. =
I repeated it a couple of times, and it was much cleaner, but sounded odd. =
I tried noise removal, which I'v never used before, using a quieter part of=
 the track as a sample, and that sounded really odd.

The call can be heard several times during the 1m20s recording, and a sonog=
ram easily shows their location. Tom has provided a sample sonogram on that=
 page.

Peter Shute