Thursday, September 27, 2012

Shifts

A non-name creek on a misty morning in late September
While sitting on Waggoner’s Gap hawkwatch during a slow period recently, the gathered veteran hawkwatchers started to talk about how hawkwatching has changed over the years. Notably, we all remembered the bad old days after DDT, when bald eagles especially were very scarce. At that time I had a cabin near Hawk Mountain Sanctuary, and the regulars there had a tradition of toasting each eagle we’d seen with some alcoholic beverage down in the parking lot after the day’s hawkwatching was over. Often there was nothing to toast, and when we did toast the eagles, it was rarely more than one or two. A good day was perhaps three. We gave up the toasts after the day we saw seven, as none of us was fit to drive afterwards. And yet now at Waggoner’s Gap and elsewhere eagles are common, and a good day is more like 20.

Our discussion on the mountain drifted away from eagles and moved into other species of birds. We all remembered the first black vulture we’d seen on a Pennsylvania hawkwatch, an event that only occurred perhaps 15 years ago. Now, in this area, no one lifts a finger when a small flotilla of these birds that used to be a more southern species drifts by. Someone joked that if we all live long enough we’re likely to see the first magnificent frigatebird fly by. Well, perhaps in a thousand years.

It’s not just my area that is seeing the shift. Black vultures move ever-further north, but even turkey vultures are counted in much higher numbers at the Canadian sites than they were 30 years ago. Back then the year’s results were often under 100 birds, where now a normal year at an Ontario site produces well over 1000 birds.

The shift is seen in non-raptors too. In my area until perhaps 10 years ago, no one ever saw a Carolina chickadee. We had the black-capped chickadee. Then I started seeing birds that were clearly a mix of Carolina and the black-capped. On Roundtop the black-cappeds hung on far longer than EBird wanted to allow (I think my elevation helped), but now even I see only Carolina chickadees. Even a bird I would call a mix is rare.

This shift of southern species into areas that used to be outside their range is ongoing. Carolina wrens? Even as recently as 10 years ago they weren’t common here. I can remember my grandmother telling me that she never saw redbirds, as she called the cardinals, when she was a girl, which would have been around 1900-1910. In my own lifetime, they have always been common.

The plants and insects that feed these traditionally southern species shifted first. Pawpaws are moving northward, and they were always a tree that was rare here on what used to be the northern edge of their range. They are still uncommon but less so. More traditional species, like the eastern Hemlock, are losing ground.

Unless a meteor hits the earth fairly soon, I will not live to see the world shift back to the climate of my own youth. The shift is well apparent and still accelerating. It’s only because I notice such things—and usually associate with others who also notice—that the change is so noticeable to me.

1 comment:

Amish Stories said...

Happy Fall folks. Richard