Where can i find information on the brown tree snakes population?

I am looking for a good source of graphable information on the brown tree snakes population in Guam since its introduction. I have tried the first two pages of the google search query "population of brown tree snakes in Guam since introduction" with and without quotes and in almost every possible phrasing. A web site is preferable. Where can i find information on the brown tree snakes population?Perhaps these are helpful:

http://oregonstate.edu/~masonr/pages/sub鈥?/a>

distribution native and in Guam:

http://oregonstate.edu/~masonr/pdfs/056m鈥?/a>

and more in

http://oregonstate.edu/~masonr/pdfs/093p鈥?/a>

http://planet.uwc.ac.za/nisl/Invasives/A鈥?/a>Where can i find information on the brown tree snakes population?sEARCH iT iN gOggle and like search in what ever categorey its in and it should come out.