It's not that they've taken offence at last summer's calls for their extermination and are leaving in a huff (you'll remember ornithologically illiterate Nicole Lawder, MLA Liberal spokeswoman on the environment, called these proudly Australian natives unAustralian introduced pests and asked the government to exterminate them) but just that they have the good sense to forsake Canberra in the winter.

ANU honours student and koel authority Laura Johnson explains that Canberra's koels spend winter in balmy PNG (giving Canberrans who resent their repetitive call a bit of a respite).

Johnson says that some imagine that the new, fledgling koels, emerging this season in the nests of other species the koels (cuckoos) lay their eggs in, will fly away to PNG in family groups so that elders can show them the way. But she says this is codswallop, and that Canberra's new, youthful koels will fly alone to PNG using ''a magnetic kind of a compass'' that migratory birds have in their brains.

For some of us the koels' feats of navigation add to their array of charms, and we find their slowly increasing presence in Canberra (Johnson knows of 15 fledglings this season) a blessing.

Lawder is reliably reported to have been badly embarrassed by her koel blunder (yes, just five minutes' Google homework would have set her straight and saved her blushes). But if she and her blushing staff want to enjoy some continuing education in this field then with all of us they're invited to this Thursday's meeting of the Field Naturalists Association of Canberra. It's at 7.30pm, in the EEG seminar room, Gould Building (116 Daley Road), ANU, and Laura Johnson will be presenting her koel research.

It's exciting stuff, for example, there's film of what happened when she used deceased but lifelike-looking birds to see if the sorts of ACT birds that koels might exploit are any more upset by the presence of a koel than by the proximity of any other species. One live red wattlebird is driven into a frenzy by a (late) koel and tries (literally ) to knock the stuffing out of it.

There'll be no koels around for frosty Anzac Day's Dawn Service (they'll all be basking in PNG) but of course there will be the currawongs that always contribute to that sacred occasion. Here, with Anzac Day looming and as a reminder to get out your mittens and your beanies, is an excerpt from John Janke's sensitive, hitherto-unpublished poem Currawongs And Crescent Moons - Anzac Dawn In Canberra.

Early verses portray thousands of us and our candles at the Dawn Service, singing the ''soft and solemn'' hymns, as light asserts itself and as we see Islam's holy symbol the crescent moon in the sky (we fought Muslims on Gallipoli) and hear the ancient Australian sound of the currawongs.

As Venus holds the crescent close

To the moon's thin arc of light

The early sounds of nature

Of Australia's bushland flight

Echo through the dawn's

dim light

In a sacred holy way

As Currawongs

and a Crescent Moon

Give Rise to Anzac Day.

As Islam's holy symbol

The crescent moon's transfixed

Above Gondwana's forests

In a strange iconic mix,

As thoughts go back

to the Dardanelles

And an unforgotten fray

As Currawongs

and a Crescent Moon

Bring Peace on Anzac Day.

Canberrans' already deep appreciation of Mount Majura (even if only admired from afar it is a shapely monadnock in our landscape and a vital habitat for our fauna and flora) will be deepened by some wonderful news. A rare orchid species has just been discovered there. The Bush Capital is a little bit bushier than we knew.

Orchid-alert naturalist Aaron Clausen was out and about on the mountain on the weekend in the wake of the recent rains and came across some clumps of the discreetly spectacular large autumn greenhood, Diplodium revolutum.

The ACT's bushland is blessed with dozens of species of orchids (there are more than 50 species at the floral hot-spot of Black Mountain alone) but he explains that the significance of this discovery is that this species has never been seen on Mount Majura before, even though naturalists' records for that bailiwick go back for more than 100 years.

''So this is a first for Mount Majura and an extremely positive find for the capital,'' he rejoices.

For those readers not au fait with our native flora, ''orchid'' will conjure up thoughts of the gaudy, florally bogan, hothouse orchids sold by florists. But the native orchids of the ACT are mostly dainty and discreet, only revealing their complex charms when you get up very close. ''Canberra's really clever and tricky like that,'' Clausen thinks. ''A place can look like just another patch or ordinary old bush but then it's stunning what you can just come across that's been staring you in the face all the time.''

Aaron Clausen contributes to Canberra Nature Map which is at http://canberranaturemap.org/