IN Artemis Cooper's fascinating biography, just published, of the peerless prose stylist and travel writer , soldier and adventurer, Sir Patrick Leigh Fermor -- who died last year aged 96 -- there is mention of a sea creature called a gorgona, a "dangerous double-tailed mermaid known to Greek fishermen", who holds a boat in one hand and an anchor in the other.
The gorgona is reputed to rise out of the sea and seize a craft by the bowsprit crying, "Where is Alexander the Great?" If a sailor answers, "Alexander the Great lives and reigns," all will be well. But if there is an incorrect response she will pull the boat beneath the waves and all hands will perish.
Paddy had a gorgona tattooed on his shoulder; he was a powerful swimmer into old age.
There was no sign of a gorgona sunning herself on the great rocks jutting out of the plunging breakers as I plodded along a coastal path. But this was on the coast of southern Portugal and not Crete where Major Leigh Fermor's greatest adventure took place during the German occupation in the Forties when a small group of patriots kidnapped the local military boss, General Kreipe, and spirited him off the island.
That gripping story may be best remembered by moviegoers as Ill Met by Moon- light, with Dirk Bogarde in Paddy's role.
There may have been no mermaids on the Algarve beaches, just some human ones taking the sunshine and best of days as swords of summer still shimmered in November. Painted Lady butterflies and a hummingbird hawkmoth, groomed as in fine silk, flitted for the nectar of wayside blossoms.
Crag martins (Ptyonoprogne rupestris) live on the cliff faces and zoom energetically for insects like their sandy cousins but they stay around in Portugal and Spain and don't migrate for winter in Africa.
They are bigger-bodied than the sandies, exuding confidence as they skirt high-rise developments taking in reflected heat.
Their communication calls are fairly weak -- unlike the brownish bullies of the evening, the tree sparrows (Passer montanus) and, occasionally, rock sparrows (Petronia petronia) which look like house sparrows (P domesticus) but with a pale crown-stripe and tiny inconspicuous yellow breast spot.
Tree sparrows take over roosts on streetscapes in a busy, noisy co-mingling of frantic activity before a sudden settling as night falls.
This noisy roosting is very reminiscent of the flocks of pied wagtails (Motacilla alba yarrellii) in the great London plane trees of O'Connell Street in bygone years, disrupted, perhaps permanently, by the tree replacement programme put in place by Dublin Corporation several years back.
The attraction for the sparrows of the Algarve is similar to what was once a unique Dublin phenomenon -- the warmth of street lights, rising heat and shelter and undisturbed social intercourse for the birds. The Dublin Naturalists' Field Club logo, from the 1880s, features a wagtail. Where have they gone?
The Portuguese sparrows chatter loudly in their evening trees as they discuss, perhaps, the most likely spots on their daily wandering for food. I pass beneath them as I set out on a similar quest and also, as a bonus, to listen to another traveller tell of his adventures on the rocky sea coast of Crete.