Friday, May 26, 2006

West Nile, Global Warming, and Cyanocitta Cristata

I think I'm going to be on a bit of an environmental kick over the next week or so, and will try eventually to write something on the whole "in the 70's scientists thought we were on the verge of a new Ice Age" argument that gets flung at you by recalcitrant righties whenever the topic of Global Warming comes up.
But today's post is inspired by the sighting of a young pair of Cyanocitta cristata (Blue Jays) at my back-yard feeder this morning, the first I have seen since about 2002 or 2003.
I'm not sure about the rest of Canada, but anyone who lives in the GTA and cares about such things may have been wondered where all the blue-jays, and all the crows for that matter, have gone over the past several years.

The short answer is that West Nile Fever got 'em. Jays and crows are especially susceptible to the disease, and their numbers in and around Toronto were decimated when it arrived in Canada. So while the effects on the local human population seem to have been pretty mild (I think there were only a few deaths reported locally), two key players were almost entirely removed from the GTA eco-system.

Now with crows you might ask "Who cares?". But, personally, I admire them. To me a murder of crows is an impressive sight, the avian equivalent of a leather-clad motorcycle gang. They are extremely intelligent and have been known to occasionally employ tools. At one time (when such things were legal), if you got them young enough when, for instance, they had fallen out of the nest, they could be made into terrific pets.

But blue jays, on the other hand, I think everyone likes. They too are clever birds. If your feeder isn't big enough for them, they'll just shovel seed out of it with thier bills, then scare off the smaller birds and eat lunch on your lawn.

In any case West Nile severely depleted both local populations.

Now, one of the predicted effects of Global Warming has been that mosquito-borne diseases will gradually spread into more Northerly climes as warmer, more humid weather in those areas brings about an increase in potential hosts (ie more mosquito's). The appearance of West Nile in North America and Canada especially can be seen as evidence confirming this prediction.

So the next time someone asks you for proof of the deleterious effects of man-made climate change, you can point to your bird-feeder.

1 comment:

Anonymous said...

maybe YOU should not be interfering with nature by creating artifical bird feeding habitats in your backyards.

Maybe YOU killed off the blue birds !!

global warming ya right . . .