Simplify the following text for a Grade 10 native English-speaking person.
Original: The 19 cm long , 47 g weight Black-headed Grosbeak is a migratory bird , with nesting grounds from southwestern British Columbia , through the western half of the United States , into central Mexico .
Simplified: The Black-headed Grosbeak is a migratory bird . It has nesting grounds from southwestern British Columbia , through the western half of the United States , into central Mexico .