Sounds like a bird nest under the hood of my car-

This is my 2001 Toyota Tundra, this sounds come from under the hood when I drive it and also when parked with engine running. Here is a link:

Any idea what this might be from and/or how to fix it?
Thank you very much,

First guess is that it is one of the accessories or one of the idler pulleys or tensioner pulley.

Grab the tube from an empty paper towel roll and put one end around your ear, point the other end at each accessory and pulley until you isolate the sound.