Saturday 21 April 2018

Blown in the wind, a king flies on

King: A Monarch at Straffan Butterfly Farm Photo: Tony Gavin
King: A Monarch at Straffan Butterfly Farm Photo: Tony Gavin

Joe Kennedy

On Tuesday morning, I spotted a king - or a pretender - as I walked past a large apartment block in a holiday resort. The temperature was in the early 20s, and rising.

This was a butterfly that seemed almost as big as a wren, fluttering its wings in flight bursts, frustratingly, for me, not alighting on an enticing bloom for a closer look.

Down along the front of the building it made its restless, swooping way, crossing a driveway to briefly settle on greenery before rising to cross a two-lane road. There was time for a closer look. Several tourists followed my curious drift to observe this magnificent insect of orange-brown wings with black worm spines on a pristine sheet visible when folded.

I concluded that this was a Monarch butterfly, a rare vagrant from across the Atlantic, or another that mimics it, called a Viceroy, not poisonous to birds as is the Monarch from feeding on milkweed, whose toxins can do a nasty job on a bird's stomach.

It had been at least six years since I had last seen one - also near this place but closer to the sea - among the bougainvillea, roses and other decorative plants on Portugal's southern coastline. About 50km further west is Sagres and Cape St Vincent, dubbed the end of the world (o fim do mundo) with the ghosts of Magellan and Henry the Navigator in the ocean mists and towards where this American had been blown in the wind.

There is good news about this species in that being one of the world's great wildlife migrations, numbers are picking up again after crashing severely during the past 20 years. The Monarch migrates in vast 'flocks' up and down the Rocky Mountains from Canada to Mexico, and with eastern passages some insects get blown to Bermuda and thence to the Azores, Madeira and southern Iberia - and sometimes as far as Cornwall. This butterfly can also turn up in Australia and New Zealand where it is known, appropriately, as The Wanderer.

The World Wildlife Fund reports that the number of Monarch butterflies spending the winter in the forests of central Mexico has risen for the second year running, covering 10 acres of coniferous trees in 12 separate colonies, an estimated 140 million insects. The population is back up to the level of five years ago. The insects hang out in Mexico for winter, rouse in spring to fly back north, laying eggs on milkweed plants as they travel - and then dying. The caterpillars feed on the milkweed, life goes on and a new generation continues northwards.

But all is not so simple. It is a continuing battle for survival, from illegal logging in Mexico to loss of milkweed habitat through changing land use and herbicides in the US. The US Fish and Wildlife Service is working with conservation groups to protect the weed growth along migratory paths.

Monarch migration remains something of a mystery. The butterflies do not live long enough to make the round trip, so several generations breed and die on the journeys. Science says chemical signals, solar navigation and inherited memory keep the species on the navigational route. My lone flutterer was a rare traveller in one of nature's cosmic mysteries.

Joe Kennedy was writing from the Algarve, Portugal

Sunday Independent

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