A Blackbirds lament

[Keith]

The pellet hit your breast
and took my breath,
my mind followed a rising panic
of realisation, I had taken a life. ... correct to realization

I had laid the breadcrumbs ... should be a comma here.
hid behind the garden wall ...should be a comma here.
waited in silence as you landed,
lined the sight, squeezed the trigger
it was all my responsibility. ... too many items in this series, a mouthful. Try breaking it up somehow, like putting "lined the sight" on its own line and then "squeezed the trigger" in another. This will build a bit more tension when its being read. Or you could combine "hid behind..." and "waited in the...". Something like "

Your body was still warm
as I tried to revive you
soft like you were filled with water. ... try "like you were filling up with water", 
The colour of your beak
the clarity of your eyes
the perfect design of your feathers
all wasted by me.  ... we already know the killer, it feels redundant to keep stating it, just put "all a waste" or something to taht regard
I buried you in the garden
and made promises
I have kept. ... try "I would keep", I have kept sounds a little off

The following year I saved
a fledgling thrush
from the mouth of a cat,
raised it on worms,
set it free when the weather
turned warm,
gave it back your life.

He only visited the garden
a few times, ... you come up with something more interesting than 
but I kept looking.
Maybe he made new friends
or maybe the other birds told him
what I was really like.

As a whole I would even recommend starting with the third stanza, as this will create some tension when the reader won't quite know what's happening right at the start of the poem with the line "your body was still warm while I tried to revive you". Then you can incorporate the important parts of the first two stanzas into the remainder of the poem, like bread crumbs, etc.

Also, although I like the simplicity, there is not a lot of interesting language happening here, it is a little too obvious. Be more descriptive, don't just tell us that the beak had "colour", show us, "the blues, the greens". I would also recommend examining the lines of your poem and see the minimal amount of description necessary for you to still convey the same information, for example your line "when the weather turned warm", is a thousand times more emotive than if you had said "when spring came", the reader's smart. You can even play up the reveal of the 'you' in this poem, draw it out, tease us with it, take the reader for a ride.

A couple ideas for you to run with.

Hi PB
Thank you for taking time to write such a considered reply all comments are very helpful, I am committed to an edit on this one as I think all the good advice on this thread will make it so much better. I have had a few goes but as yet I'm not happy with the result so its still in WIP pile. Thanks for bringing it back to the top. Keith