In Stephen Dunn's poem "Hawk," why does the speaker consider the issue of owning or not owning the hawk that crashed into his window?

In Stephen Dunn’s poem titled “Hawk,” a hawk accidentally crashes
into the window of a home owned by the poem’s speaker. At first the speaker assumes that
the bird is so seriously injured that it will not be able to fly again and may thus need
to be taken care of, and thus possessed, by the
speaker:
 

I thought
[it]
 
might become mine after it crashed
into the large
window and lay
one wing spread, the other loosely
tucked . . .
(4-8)

 
Instead, however, the hawk
manages to get up, although dazed, and resume flying.
The speaker’s reactions
to the (temporarily) injured hawk can be viewed from a number of different perspectives,
including the following:
·         The speaker seems to desire to help the
hawk from altruistic motives. After all, the speaker had no idea that the hawk would
crash into his window. He seems to regard the crash as an unfortunate accident and seems
to think that he can help the hawk survive by taking care of it if it is too injured to
fly again. One might even say (from this perspective) that the speaker’s motives are
“humane” in the fullest senses of that word.
·         On the other hand, the
speaker himself seems to suggest, in the opening two lines of the poem, that his motives
for wanting to take care of the hawk were somewhat selfish and even
weak:

What a needy, desperate thing
to
claim what's wild for oneself . . .

          This less attractive interpretation
of the speaker’s motives (an interpretation offered by the speaker himself) is supported
by his later reference to his thought that the hawk “might become
mine” (5; emphasis added). Such phrasing implies that the speaker’s
motives may not have been entirely altruistic but may in fact have been tinged with
selfish possessiveness.
·         However, the poem is made even more
complicated by the fact that the speaker seems to be criticizing himself and his motives
in the lines just quoted. His selfish possessiveness, then, is somewhat offset by the
fact that he realizes that he is capable of feeling selfish possessiveness and that he
rejects this motive in himself.
In short, the poem is a complex work of art,
not merely an expression of simple, uncomplicated thoughts.