Human: What are some of the causes of the decline in population of marine birds in the Puget Sound? Assistant: 
A survey completed by the Western Washington University (WWU) reports that the total number of marine birds in the Puget Sound is decreasing. The cause of this decrease in population is not clear, although researchers suspect likely causes such as pollution, non-native species, and collisions with man made structures, abandoned or lost fishing gear, some fishing practices, unavailable food sources, and loss of habitat. There has been a decline of surf scoters, white scoters, and black