The poet starts the poem with a sentence that is very direct and describes his feelings from the beginning which is "I know what the caged bird feels, alas", the word alas is an expression of the grief and sadness the poet is going through.
"When the sun is bright on the upland slopes, when the wind stirs soft through the springing grass" here the poet uses alliteration twice using the letters w and s.
"And the river flows like a stream of glass" the poet uses a figure of speech which is a simile to compare the river with glass, the purpose of this simile is to enhance the beauty of river stream by comparing it with glass that is to say that both are calm and clear.
"When the first bird sings and the first bud opes, and the faint perfume from its chalice steals" here Dunbar is describing the nature around the caged bird in more details by specifying the season as spring, which we realized from the birth of a new bird and the birth of flowers which are all signs of the beautiful season. A metaphor is also used here which is comparing the smell of the bud or flower with a chalice, a chalice is metal drinking cup that is used by Christians to serve wine in church, so that is to compare the soft and pale smell of the new flower with the metal cup.
Then he ends the verse by the repeat ion of "I Know what the caged bird feels" to emphasize on how they are both the same.
Then he starts to describe the physical battle the bird is going through after seeing the beautiful nature around him. "I know why...