A split-sample design is used to test for a difference between mean willingness to pay (WTP) for protecting the Mexican spotted owl versus protecting 62 threatened/endangered species which includes the Mexican spotted owl. The multiple bounded contingent valuation method is used in a mail survey of U.S. residents. The mean WTP amounts are statistically different at the 0.1 confidence level indicating the multiple-bounded mail survey passes the scope test. The range of estimated benefits of preserving the 4.6 million acres of critical habitat for the Mexican spotted owl substantially outweighs the costs of the recovery effort.