Hello ERJ Cat!
Dont expect any critics from me here - rather questions!

After learning six new words and looking up what exactly a sonnet is (finding out that in German it is a Sonett!) , discovering the different rhyme forms of the sonnet types, not finding what a Spencerian sonnet is exactly (but yours is clearly an English one) and finally reading about thesis, antithesis and synthesis, I didnt find much I could say what is not already said.

What made it easier for me to grasp the meaning (with not knowing all words in the beginning)was to arrange the three stances more clearer, then the different contents, the description, the movement and then the Man versus Nature was more clearly visible.

Its throat adorned with smoke as from a pyre
Ablaze with yellow, flaming up its breast,
Enveloping its crown these plumes of fire:
The Altamira Orioles bright crest!

Its little perch it quickly will divest
At shadows slightest hint of passing near,
A whistle and it springs forth from its nest,
Were left with musics echo chasing fear.

Though, looking on one might feel cavalier
To dominate the world that one descries;
Yet lapsed within the winds that cruel frontier:
Upon those smoky wings Time quickly flies!

This imminence of fate lay just before
Our politicians and the wastes of war.

I thought about as well, what could bring those first two stances closer to the third and lessens the throwing like soulsease said. Before reading up the sonnet I just thought, add two more lines in the beginning to embrace the bird-lines and tie it so together. Well, that being no solution, the only possibility would be to find a heading which has the same effect.

A last question to the last line: I stumbled over the wastes - does it have one or two syllables spoken out? Like wasted? I couldnt bring merriam webster to pronounce the plural for me ;) .

Thank you :)
***Astropic of the day***

""For me there is only the traveling on paths that have heart, on any path that may have heart. There I travel, and the only worthwhile challenge is to traverse its full length. And there I travel looking, looking, breathlessly." ~Don Juan