"Boing" material

[JDlugosz]

The "Boing" and Comfy Perch I've bought seem to be wire wrapped in some kind of cordage. Any idea what kind of string that is, and how to go about making items like that?

 

[JerseyWendy]

Here you go: Bird Toys - Make a BOING - Birds

And here's another one: http://www.parrotforums.com/do-yourself/33466-i-ve-made-sisal-boing.html