<em>floats downstream, the trade winds soft, and dawn-bright lawn</em>
Explanation:
Hi, after reading the poem I find the following three ideas as metaphors representing freedom.
A bird that '<em>floats downstream</em>' is not tied to a cage, it is being carried by nature. This poem is comparing a free bird to one in a cage at all times.
'<em>the trade winds soft</em>' is also used in a paragraph describing a free bird and the way it flies freely when it thinks of another breeze. In a cage, it would go nowhere.
'<em>dawn bright lawn</em>' is the surface where the bird can find his food (fat worms) instead of seeds given to birds in a cage.
Mary Cassatt, one of America's first great female painters, has one of her paintings of a mother and daughter hanging in the White House.
Mary Cassatt's painting "Young Mother and Two Children" hangs in the White House as testimony for her importance as one of America's first great female painters.