Tuesday, 16 September 2014

Wrens in a warming climate

Singing Wren, Howth Co. Dublin ( c. Liam Kane)

Diary of an Ornithological Exile

 By Ray O’Hanlon

I’m getting a little confused over this climate warming thing.
First up, my personal climate starting warming up the minute I made permanent landfall in the American North East.
In my first summer in New York I was reduced to carrying a book on the subway that had to do with the race between Scott and Amundsen for the South Pole.
Somehow, reading about men who had frozen to death would be a counter to the temperature on the platforms that first July and August.
That would have been roughly 40 degrees centigrade. It was one of those summers
Reading the book turned out to be cold comfort. It was just damn hot no matter how gruesome the description of the great southern continent when it decided to be mean.
Of course, in those early American days I, along with just about everybody else, had never heard of “global warming” or “climate change.”
New York City was its own micro climate anyway.  So in the summer I roasted, and in the winter I froze.
It was decidedly not East Coast Hibernia.
A few years on, now with a new and growing family, my wife and I left the city and migrated north of Gotham into the Hudson Valley.
Our home is just a train ride away from the mayhem of Manhattan, and while we are far from being country folk, we are a little removed from the dense suburban model as well.
We have a garden, a leafy one. And unlike, say, the Amazon rainforest, it has become steadily leafier down the passing years, now 21 of them since the big move.
Trees, bushes and grass mean birds of course.
I have a tick list for the garden and the sky above that is quite impressive - in large part because it is aided by the nearby Hudson River, as great an avian flyway as it is a watery passage.
That list tells a little story that gives a clue to the very real phenomenon that is the warming of our climate.
It’s a tale of two Wrens.
When we moved in that late summer of 1993 I carried out a rapid assessment of our new garden’s avian inhabitants. Who were they, who were their people?
One of them was the House Wren, a New World cousin of the Eurasian Wren that all in Ireland are familiar with, as much for the racket it makes than anything else.
Wrens are not shy and retiring, though the House Wren did seem a little more low-key than the churring wrens I had been familiar with back across the ocean.
Maybe that’s why House Wrens, actually the most widely distributed bird in the Americas, aren’t hanging out in our garden any more.
They have been bumped by the larger and much louder Carolina Wren, which, as its name suggests, is more of a Confederate than a Yankee.
Carolina Wrens have been edging northwards in the U.S. since the middle of the last century.
Birds being flying thermometers, this would suggest the pull of a warming climate going back years before anyone mentioned, well, a warming climate.
Carolina Wrens do not like cold and they easily suffer population crashes in bad winters. But they have been hanging tough in whatever the latitude is outside the back door.
And the garden, their world, has been changing.
Twenty years ago the growth season for weeds and the like would settle down in high summer.
Temperatures would be high, but a lack of rainfall would tamp down unwanted fecundity.
Not so in the past five years.
The hose has been mostly left coiled and corners of the garden have taken on an Amazonian aspect with creepers and vines growing at Jack and the Beanstalk rates.
I pulled a vine off a Juniper the other day that was thick enough for Tarzan to swing on.
Meanwhile, the Hemlock trees have clearly been struggling, and the rhododendron has been looking distinctly unhappy.
This kind of advance and retreat is new, and it seems to be permanent.
And so too are the Carolina Wrens, welcome guests for sure, but strongly in need of training in the delights of monastic contemplative silence.
A few days from now, back in the concrete canyons of Manhattan, the United Nations will be convening for its annual General Assembly.
This year there will be big discussion about global warming in the planned UN Climate Summit.
Politicians from around the world will be convening, thus, of course, adding to all the hot air.
I’m thinking of showing up with a leaf bag full of tropical hummus from a supposedly temperate garden, and a Carolina Wren on my shoulder.
Meanwhile, back at the homestead, I’m keeping a sharp eye out for a first Bird of Paradise. 

Ray O’Hanlon is a journalist, author and onetime member of the Irish Wildbird Conservancy.

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