As you can see from the comments, it's not insoluble, but you DO have to start the search with some version of a search that describes the sound! There are really two approaches here...
Stephen started with the Wikipedia article on wind chimes even though I said it WASN'T a wind chime. I wasn't trying to misdirect anyone, but it was a great move. One thing to remember about Wikipedia articles is that they often include a large amount of disambiguation information, that is, ways to discriminate different variations on a them. So Stephen did a smart thing by going to Wikipedia-wind-chimes and reading it to find information about related-but-not-the-same-thing information. Nice move! He's right--at the end of the Wikipedia article about wind chimes is a reference to "Mark trees"... which is what this sound is.
By contrast, David and Fred both did what *I* did -- I started with a simple description of what I was hearing and then looking around for samples that sounded very much like what I was searching for.
The heuristic we all used was to find the closest thing by following a description, then hunting around in the space near by.
Bravo, folks! These are both excellent methods to solve difficult-to-describe search problems.
Let me summarize them as follows:
Use diambiguation information: And, as we've seen on more than one occasion, Wikipedia often offers a "disambiguation page" for similar terms or concepts (see, for example: discrete disambiguation)
In this example, going to Wikipedia for the closest term you can think of that's related to the object in question ("wind chime"). Even if you don't get exactly a perfect match (as Stephen did), you'll often learn a good deal in the process.
Browse around in a collection of clearly-related items. A good strategy to find something that you find difficult to describe is to look in a collection of items that are clearly related, picking up terms and concepts that might prove useful to you. In essence, you're looking for an album of samples that make a collection of near-hits. The more skill you have in describing your target, the better (and smaller) collection you'll have to search.
Nice job everyone. Keep searching!