Laudator Temporis Acti

Gerard Manley Hopkins, Spring:

Nothing is so beautiful as Spring —
    When weeds, in wheels, shoot long and lovely and lush;
    Thrush's eggs look little low heavens, and thrush
Through the echoing timber does so rinse and wring
The ear, it strikes like lightnings to hear him sing;
    The glassy peartree leaves and blooms, they brush
    The descending blue; that blue is all in a rush
With richness; the racing lambs too have fair their fling.

What is all this juice and all this joy?
    A strain of the earth's sweet being in the beginning
In Eden garden. — Have, get, before it cloy,
    Before it cloud, Christ, lord, and sour with sinning,
Innocent mind and Mayday in girl and boy,
    Most, O maid's child, thy choice and worthy the winning.

The pear-tree and the thrush are also juxtaposed in Robert Browning, Home Thoughts from Abroad:

Hark, where my blossomed pear-tree in the hedge
Leans to the field and scatters on the clover
Blossoms and dewdrops—at the bent spray's edge—
That's the wise thrush; he sings each song twice over,
Lest you should think he never could recapture
The first fine careless rapture!