> Choosing a species with a defined winter range and analysing changes in
> numbers and the location of the boundary might give an indicator of more
> "global" temperature range. However indicator species cannot be chosen until
> the effects of global warming on a given geographical region are known. For
> example, some climate models predict that western Europe will become colder
> and wetter as a result of increased global temperatures. I would expect more
> continental climates, ie North America to be a bit more "predictable" than
> maritime climates such as western Europe, however the changes caused by global
> warming are much more chaotic than simply an increase in "local"
> temperatures.

"Amen" to that last statement! Your comment regarding continental climates
only applies to part of North America, of course, as our climate is
essentially maritime, at least west of the Cascades.

One problem for residents of the PNW is that, as far as I know, there is
no consensus on is the effect warming will have on the El Nino phenomena.
This phenomena affects precipation in much of Western North America. One
problem is that (again, as far as I know) no consensus among climatologists
as to the extent the phenomena affects North America. Though over the years
the consensus has generally been "gee, more than we though ten years ago!"

At least oceanographers have learned a lot about how the mechanism works
within the ocean.

> Speculation: On plan of attack might be to choose, generalist species, which
> are able to find food across a broad range of habitats - for example the
> beloved Starling. Assuming that food availablity is less of a problem for such
> species then climatic conditions might be the limiting factor on either their
> winter range, warmer equals wintering further north, or breeding success,
> more food available earlier in the year = more broods and more young reared.

Here's another speculation: the effect of climate change may be more
easily handled by choosing plant species, or perhaps non-migratory
animal species, rather than migratory birds. Sorting out all the
possible causes for changes in numbers or ranges of migratory birds
would seem inherently more complex than doing so for sedentary species.

> Life is never that simple, SIGH.

Life is never simple, period! I won't SIGH, though, 'cause I might
be bored if it were!

-Don Baccus-