4692
In it he plays Robert Stroud , a federal prisoner incarcerated for life for two murders , who begins to collect birds and over time becomes an expert in bird diseases , even publishing a book .
 Robert Stroud
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Robert Stroud