Ultrasonic natural sound recordings

[Nicol Harper <nicol.harper@xxxxxxxxx>]

Hello. I am new to this list.

I am making at set of natural sound recordings. I would like to be able to record frequencies up to at least 40kHz, with a microphone that is as insensitive to sound-source direction as possible and also preferably with with a fairly flat frequency response. I will probably also want to avoid sounds from vibrations and knocks to the microphone during movement of the microphone.

I am currently using a zoom H2 recorder on mono mix with a 96kHz sampling rate, and carrying it carefully or using a tripod.

http://en.wikipedia.org/wiki/Zoom_H2_Handy_Recorder

I was thinking of maybe using a zoom H4 with a Knowle FGO microphone.
http://www.avisoft.com/usg/KnowlesFGO.htm
http://en.wikipedia.org/wiki/Zoom_H4_Handy_Recorder

Does anybody have any other suggestions, or know of anything I should watch out for?

I can spend up to a few thousand dollars.

All the best,

Nicol Harper