Hammering-Castle-Bird-Man

Thinkin' there’s some solitude
In starin' off at the furthest view
While closer up the assault begins
The castle that’s a bird comes
Hammerin' funnel-capped but steadfast too
Sharin' some of your attributes
The hammer blows, the hammer blows
The castle bird’s arms throw
And throw while movin' its wall
With creature feet nearer and nearer
Without retreat musterin' resolve
You get the clue you’ve met the enemy
Guess who? It’s you