Poetry collections tend to be miscellaneous. They say: all change here, please as one alights from one poem and steps into the next – this is the reader’s undertaking. One of the most unusual things about Karen McCarthy Woolf’s debut is that it is held together by a single event – in a sense, a tragic non-event – the stillbirth of her son, Otto, in August 2009, and it is this emotional core that holds the work together, gives it its concentration, charge and flow. An Aviary of Small Birds is a collection that can, with the exception of a handful of poems, be read as a narrative. Otto’s death gives birth to the book.

There is nothing conventional or chronological about McCarthy Woolf’s approach. In the poem entitled Of August, several pages in, she turns her life into copy – were the subject not so painful – in a playful way. Two agents and a couple of publishers have attended a “panel discussion” at a university. On the train home, a student writes down the synopsis of a novel she plans one day to submit to them:

“… the story of a woman, The Protagonist, who, after many years of trying to conceive, is finally pregnant. Her Best Friend is bipolar and has just been diagnosed with inoperable cancer, aged 36.”

The plot gathers momentum and one can see that the turning of life into fiction is a distancing device that brings its own comfort (there will, incidentally, be poems – excellent poems – about the friend whose struggle parallels the Protagonist’s own). Meanwhile, this is one way to spell out bald facts:

“Unfortunately, the birth does not go as expected and the baby dies during a long labour on the 7th of August, two days after The Best Friend’s birthday. There is evidence to suggest the hospital is at fault, although the consultant who goes over the autopsy results with The Protagonist and her partner advises them to concentrate on rebuilding their lives. He also tells them about his 18-year-old daughter who was killed in a car accident two weeks before she was due to take up a place at Oxford.”

Impersonal prose organised into a shape – this is an exploration of prosaic limitation within poetry, a reminder of how helpless and abbreviated ordinary language can be in the face of tragedy. This poem is offset by McCarthy Woolf’s powerfully contrasting poetic voices, some more complex than others, that speak with freedom, exploring a life snuffed out before it had a chance to blaze. Mort-Dieu, slender as a candle on the page, is a prayer that turns into a protest:

Our son
dear God
is dead
and gone.
His tomb
was red
with blood
and warm
as tears.
He was
born still.
Was this
dear God
your will?

In the beautiful, unsentimental White Butterflies, she makes a mourning wreath of whiteness. White lilies, white linen, white muslin, but no white relief. The poem ends with the excruciating detail: “Your tiny white vests, unworn.” She is careful not to give any of her poems unearned comfort. There are no false flights.

And yet the title poem, one of the collection’s finest, is about flight. It is filled with the idea of a life that lasts a moment “quick as the light that/ constitutes your spirit”. She ends: “The tenor of your heart/ is true as a tuning fork struck/ – and high! My love/ is the bird who flies free.” It is a tribute that can be shared, for McCarthy Woolf’s tuning fork always rings true.

An Aviary of Small Birds is published by Carcanet, £9.95. Click here to buy for £7.95

An Aviary of Small Birds by Karen McCarthy Woolf

My love is an aviary
of small birds
and I must learn
to leave the door ajar…

Are you the sparrow
who landed when I sat
at a slate table
sowing lettuces?

Webbs Wonder, Lollo
Rosso, English Cos…
Swift and deft
you flit and peck peck

quick as the light that
constitutes your spirit.
Yes, you were briefer
than Neruda’s octobrine.

So much rain that night.
Our room is an ocean
where swallows dive.
The bubble bursts

too soon, too late, too long:
all sorts of microscopia
swim upstream, float in
on summer’s storm.

The tenor of your heart
is true as a tuning fork struck
—and high! My love
is the bird who flies free.

• This article was amended on 27 November to restore missing words in the fourth verse.