[1] A Bird, came down the Walk1 — He did not know I saw —

He bit an Angle Worm in halves And ate the fellow, raw,

[5] And then, he drank a Dew2 From a convenient Grass —

And then hopped sidewise to the Wall To let a Beetle pass —

He glanced with rapid eyes, [10] That hurried all abroad —

They looked like frightened Beads, I thought, He stirred his Velvet Head. —

Like one in danger, Cautious,

I offered him a Crumb,

[15] And he unrolled his feathers, And rowed him softer Home —

Than Oars divide the Ocean,

Too silver for a seam,

Or Butterflies, off Banks of Noon, [20] Leap, plashless3 as they swim.

In a bird came down the walk
how does the last stanza contribute to the development to the theme?