Shelley is one of the most well know Romantic poets, meaning he focused on nature, symbolism and myth, the sublime, the individual, the everyday and the exotic.
One can see the presence of many of these within his famous ode. An ode is a poem that traditionally captures a complex thought or emotion through the focus on one subject. It typically has elevated diction and tone.
Shelley shows a true appreciation of the Skylark as a bird, but he also uses it to reflect its importance of singing the songs of nature and reflecting its beauty. We see his immediate connection of the bird to something more exotic than a background presence of the everyday but something more sublime when the poem begins, "Hail to thee, blithe Spirit!/ Bird thou never wert-." Immediately, he wants his reader to go beyond the initial images and associations of the bird they picture in the title.
In stanza two, he bring forth images of the supernatural or myth by writing, "From the earth thou springest,/ Like a cloud of fire." Shellety knows that most associate his "cloud of fire" with the mythical creature of the phoenix, who is an immortal bird of flame reborn from his own ashes every several hundred years.
In this moment of Shelley's appreciation, the bird even makes the sun seem less intense. He writes in stanza four, "The pale purple even/ Melts around thy flight" suggesting it is the bird who leads the light of the sky.
Finally, in the second half of stanzas by Shelley, we get beyond praise of the bird and see his connections as he writes , "Like a Poet hidden/ In the light of thought,/ Singing hymns unbidden." The bird, like the Poet (capitalized here for significance) is as vital to the world of beauty as the beauty itself because he is able to reflect it. Much like the bird's ability to reflect the beauty of the sky it flies in and then sing its praises in an equal way, the Poet is a part of the world he writes while at the same time intensifying its beauty.
In this way, Shelley admires and the Skylark and hopes to follow its similar blazing path.