What is the structure and rhyme scheme of "The Sparrow" by Paul Laurence Dunbar?

The poem is structured so that the first stanza describes a simple occurrence, and the second stanza then offers an interpretation as to the moral meaning of that occurrence. The first stanza describes the fluttering and chirping of a small bird outside the speaker's window, which the speaker ignores because he is too busy working. In the second stanza, the speaker suggests that our hearts have become "deadened" to simple things like the visitation of a bird to our window. The moral is that we should work less and enjoy the simple pleasures of life more.
Each stanza comprises four rhyming couplets, whereby the last words in each pair of lines rhyme with one another. For example, the first rhyming couplet is "brown . . . down" and the final rhyming couplet is "on . . . gone." This strict, repetitive rhyme scheme lends a simplicity to the poem, which perhaps echoes the simplicity of the poem's message.