How can I analyze the poems "Humming-Bird" by D.H. Lawrence and "Celia Upon Her Sparrow" by William Cartwright?

Both poems have birds as their subjects and the poets use the birds as metaphors for things that are no more. The hummingbird stands for the earliest phases of life, while the sparrow stands for love.
In D.H. Lawrence’s “Hummingbird,” the speaker imagines this tiny bird as very different in the most ancient time, back at the origin of life, “humming-birds flashed ahead of creation . . . ” Then and there,

. . . in some otherworld /
Primeval-dumb, far back /
In that most awful stillness . . .



Before anything had a soul,
While life was a heave of matter, half inanimate . . .

Nevertheless, the hummingbird was as fast then as now:

Humming-birds raced down the avenues.
This little bit . . . went whizzing . . .

Like other familiar life forms, it was once much larger:

Probably he was big
As mosses, and little lizards, they say, were once big.
Probably he was a jabbing, terrifying monster.

The repeated use of “I believe” shows the poem is about faith. Overall the poem encourages radically different approaches in contemplating time and the origin of life. In the last line, the speaker adds the reader, encouraging them to join in this contemplation: “We look at him . . . Luckily for us.”
William Cartwright’s “Celia” poem (also called “The Dead Sparrow Poem”) departs from an ancient predecessor, “Lesbia upon Her Sparrow” by the Roman poet Catullus. Cartwright’s poem, the speaker addresses their beloved, comparing the person to the now-dead sparrow, whose antics aimed to please the speaker:

He, just as you,
Would toy and woo,
He would chirp and flatter me.

The end of love, however, is the real subject, as the poet compares the “faithful bird” to love, or Cupid’s darts. The use of “faithful” implies that the speaker’s lover has been the opposite, or has cheated on them.

Whence will Cupid get his darts
Feathered now to pierce our hearts?
A Wound he may
Not love convey
Now this faithful bird is gone.
https://www.hummingbird-guide.com/DH-lawrence-hummingbird-poem.html

https://www.poetrynook.com/poem/dead-sparrow-0