[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
The dreaded kinglet thread...
- To: Carolinabirds@duke.edu
- Subject: The dreaded kinglet thread...
- From: Joshua Stuart Rose <jsr6@duke.edu>
- Date: Thu, 2 Mar 2000 00:42:52 -0500 (EST)
- In-Reply-To: <01BF83C0.B33DE240@TC-DSP-IP11.ASAP-COM.COM>
- Sender: carolinabirds-owner@acpub.duke.edu
Hi C-birders,
You can tell from the lack of variety here that we're in the spring
doldrums, too late to hope for any new winter irruptives, but too early
for spring migration to get exciting yet...
On Wed, 1 Mar 2000, Don H. wrote:
>
> I'm with you on the kinglets. One would have to look at, at least ten years
> worth of data to determine any kind of trend. The data I've seen posted
> here says some winters they're here - some winters they're not.
Were we looking for a trend? I thought the issue was whether there was a
singular, one-time-only mortality event this winter. The only thing which
ten years' data would tell us is whether this year's suspiciously low
numbers are within some kind of normal fluctuation boundaries for the
species.
> The wkend of the GBBC, Waynesville was dirty with GC's and RC's are found
> on almost every trip afield.
Yes, but as has been pointed out, western North Carolina - where
Waynesville is located, last time I checked - did not have terribly
out-of-the-ordinary snowfall this winter. Sure, there was some, but in
the mountains there is snow every winter. The Coastal Plain and,
especially, the Piedmont had more snow this winter than any other this
century, I think. This decade at least. And how many kinglets did
Waynesville have *before* the GBBC, and before the snow hit? Perhaps
that's where the Piedmont refugees might have fled to!
On Wed, 1 Mar 2000, Florida Nature Tours wrote:
>
> The numbers of R c Kinglets seemed to be normal this winter
> throughout the state of Florida. The numbers of G c Kinglets
> this winter has been unprecedented, with many, many times the
> usual numbers of birds in North Florida, & many much farther
> south in the state than I can remember. In fact we had 2 of
> them on the Zellwood Xmas Count near Orlando.
Again, out of the range of the unusual winter weather that nailed us
here. Interesting that Golden-crowneds irrupted into Florida this winter;
supposedly the winter finch irruption was driven by a poor seed crop in
Canada, and the hawk and owl irruption by either snow cover or a lemming
population crash. And Bohemian Waxwings are irrupting too, driven by a
poor berry crop up north, so they say. But why kinglets in the same
winter?
On Wed, 1 Mar 2000, Marilyn Westphal wrote:
>
> The question is,
> why should this particular event be harder on kinglets than on other
> song birds? Did this particular event affect their food supply more
> than the other birds?
Yes, it probably did. Most of the other songbirds that winter up here can
use alternate food sources: chickadees and nuthatches to seeds, Tree
Swallows and Yellow-rumped Warblers to berries, etc. And many of the
other species which cannot switch did struggle: there was a rash of
reports of dying Eastern Phoebes after the second or third snowfall, our
pal the Pacific-Slope Flycatcher disappeared then, and Killdeer and
American Pipits were all over the roads because that was the only open
ground they could find. Kinglets don't eat seeds, take fruit rarely if
ever, and if they visit feeders at all, they've never touched mine.
Speaking of Killdeer and Phoebe, their GBBC data is less alarming. Both
species show increases from 1999 to 2000. Neither species doubled in
number, which is what you might expect given that the number of reports
filed more than doubled. But whatever caused the drastic kinglet decline
had less effect, if any, on these other two species. Either that, or
reports from other parts of the state rose disproportionately; that's one
problem with the GBBC data, the spatial scale of reporting is a little
coarser than, say, CBC data.
One last point, before I'm all kingleted out: it has been pointed out
that kinglets regularly winter in climates where 20 inches of snow would
be considered normal. This is true, but we can't assume that the
populations which winter in our area are equally as winter-adapted as
more northerly populations. I think it was Harry who pointed out the
winter before last that the Solitary Vireos which winter here are a
different subspecies than the ones which breed in NC; kinglets which
winter at different latitudes could be equally differentiated from each
other.
Or they could be absolutely identical, for all we know. Speculating is
fun, but when you come right down to it, we only know one thing: somehow,
the NC Piedmont lost its kinglets!
I really hope I (or somebody) can find some other birds to talk about
soon...
Good birding, (please),
Josh
Joshua S. Rose
Duke University
Department of Zoology
jsr6@acpub.duke.edu
http://www.duke.edu/~jsr6/