An entry from Wikipedia, provides this background:
(Guam) is also known as a prominent example for the disastrous effects of bioinvasion: A stowaway on U.S. military transport at the end of World War II, the slightly venomous, but rather harmless, brown tree snake (Boiga irregularis) came north to Guam and killed almost the entire native bird population on the previously snake-free island. This snake has no natural predators on the island; nowadays, Guam is one of the areas with the highest snake density in the world (an estimated 2,000 snakes/km²). Even so, residents rarely see these snakes. They curl up and hide during the day, and move about on trees and fences at night. As prodigious tree climbers, the snakes allegedly caused frequent blackouts in neighborhoods across the island. They climb up the poles, into the black boxes, and electrocute themselves. Now many power poles have a slick metal sheath that prevents the snakes from climbing.
This fact sheet is also informative.
The snakes have already invaded Saipan, and the people from Hawaii have also noted the threat, and have prepared for it.
The queation is what about the Philippines? Are we even aware of this threat?