2531
As a result of abundant prey resources on Guam and the absence of natural predators apart from feral pigs and mangrove monitors , brown tree snake populations reached unprecedented numbers .
 location: Guam
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: Guam 
Answer:
 location: Guam