Michael Longley's readers will love the lyrical annotations of wild places and the quick articulate raids on the classics of his new collection, The Stairwell (Cape, £10). Eight years and two collections after his Collected Poems ended by declaring, "I am writing too much about Carrigskeewaun", he is still uncovering new reasons to return there.

In Homeland he calls County Mayo his "home-from-home-land", and it is Mayo's creatures and place names that recur as the scenes of poems that celebrate extended family and friends. Typically, Two Otters dwells on and rounds out an anecdote until it sounds like a parable, reflecting the repeat sighting of the otters it describes by renewing attention to particular words, which he plaits through a single sentence:

She toddles to the lake without a name,
Your two-year-old, and watches an otter,
Her first otter, half-expected by you
Because, when you were expecting her,
You last watched an otter from this spot,
Your body a holt for otter and child.

But Longley has of course other homes from home, and The Stairwell does not confine itself to affectionate notes on new arrivals and lamented departures. The world of Homer and the world of the Great War, as mediated through his father's experience and his study of that war's British poets, likewise generate poems as good as Boy-Soldier, whose sapling is as helpless as any war poem's subject: "A spring blizzard blows in from nowhere / And uproots it, laying its branches out. / Thus Euphorbus, the son of Pantheus, / A boy-soldier – the London Scottish, say, / The Inishkillings, the Duke of Wellington's – / Was killed and despoiled by Menelaus."

The book's closing sequence offers a biography and memorial to his twin brother, and its typical combination of snuggly intimacy and bracing analogy is often affecting and rueful. The Apparition translates Achilles's "heartbroken words": "Even in the House of Death something remains, / A ghost or image, but there's no real life in it. / All night the apparition of sad Patroclus / Has hovered over me, weeping and keening / And giving instructions. Did I imagine him? / He looked so like himself, a double, a twin."

And when his brother's ghost does appear, in The Birthday, Longley nimbly wrongfoots the reader with the sort of tender silliness he has always used to bring his subjects to life: "I've boiled organic beetroots for supper. / Will your pee be pink in heaven? Oh, / The infinite gradations of sunset here. / Thank you for visiting Carrigskeewaun. / Don't twist your ankle in a rabbit hole. / I'll carry the torch across the duach."

The tone, as ever, varies across the sequence, although occasionally his habit of mixing ancient Greek and modern English proper names seems off, as when he pre-empts Muhammad Ali and drags Troy into his childhood games: "We were combatants from the start. Our dad / Brought us boxing gloves when we were ten – / Champions like Euryalus, say, or Epeius / Of wooden-horse fame: 'I am the greatest!' / 'Nobody's going to knock me down!' Listen, / Peter, to the commentary – gruesome teeth – / Grinding, sweat splattering their arms and legs."

If it seems familiar, The Stairwell is well aware of this: it ends with a "hidden track", an extra italicised poem that dramatises his late style and the way that these poems look both backwards and forwards to his ongoing life as a poet:

forty two whoopers call
then the echoes
as though there are more swans
over the ridge

It's an engagingly wry comment on what we have just read: "over the ridge" may intimate "over the hill" and asks us to consider whether the poems in The Stairwell are the real thing or an echo of the sound of the real thing. Are the new poems like those "whoopers", calling out to us? Or, given that this is the fifth successive volume in which Longley has included a hidden track, is this poem itself, he asks, just an echo of the original of the species, his classic 1989 collection Gorse Fires (1989) and its successors? Then Yeats's October woodlands and his nine and fifty swans start to come to mind, and the fruitfulness of his search for a theme in his later work.

Some of the new poems are consciously for-the-record late work, footnotes to earlier poems, as when Second Lieutenant Tooke begins: "I should have commemorated before now / Second Lieutenant Tooke who helped my dad / Rescue Nurse Moussett of the French Red Cross"; Edward and Helen Thomas, Isaac Rosenberg, Joe O'Toole and others reappear, as does the painter Gerard Dillon, the subject of an early elegy and of Yellow Bungalow in Snow Water (2004), and here the subject of a fine three-part poem called Paintings, again acting as a model for an art that uses the west of Ireland to speak to everyday life without losing a sense of its own strangeness:

Gerard Dillon painted the blinds in his two-up,
Two-down house in Clonard Street – Irish saints,
Farm animals, Connemara dreams – so that
At evening when the gas lights were lit and
The blinds drawn, children from the
Lower Falls
Would gather to gaze at a magic lantern.

The title poem offers a view on another kind of lateness, beginning the book as it does with intimations of his own funeral ("I have been thinking about the music for my funeral"), but the life in The Stairwell will generate an appetite for further landings in Michael Longley's unique imaginative territory.