Cave swiftlets use saliva to build their nests high on cave walls. ➡ Subscribe: bit.ly/NatGeoWILDSubscribe ➡ Watch all clips from Destination Wild here: bit.ly/DestinationWild ➡ WILD BORNEO AIRS FRIDAY JANUARY 6 at 9/8c. About Nat Geo Wild: Welcome to a place so wild, anything can happen. Nat Geo Wild is the network all about animals from National Geographic, where every story is an adventure and your imagination is allowed to run wild. Get More Nat Geo Wild: Official Site: bit.ly/NatGeoWILD Facebook: bit.ly/NGWFacebook Twitter: bit.ly/NGWTwitter Instagram: bit.ly/NGWInstagram Salivating for a New Nest | Wild Borneo youtu.be/ngPs3kINUXE Nat Geo Wild www.youtube.com/user/NatGeoWild