Subject	young bird
Predicate	must hear
Object	an adult male sing the species song
Modality	Modality Occurrences
Polarity	POSITIVE
Plausibility	0.6207
Neighborhood Sigma	0.6479
Local Sigma	1.0000
Example Sentences	Sentence Occurrences Source young birds must hear an adult male sing the species song 1 Answers.com Questions