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FW: effects of winter storm on kinglet populations & parting shots
- To: "'carolinabirds@duke.edu'" <carolinabirds@duke.edu>
- Subject: FW: effects of winter storm on kinglet populations & parting shots
- From: "Don H." <donh@asap-com.com>
- Date: Mon, 6 Mar 2000 13:06:09 -0500
- Encoding: 65 TEXT
- Sender: carolinabirds-owner@acpub.duke.edu
This message may be long and many may want to skip it. Especially with
warblers, swallows, and martins beginning to make their way northward.
To echo Marylin, I am not trying to be contentious. But I believe c-birds
is a proper place to discuss differences in opinion regarding avian
ethology. The possibility of an unusual mortality event regarding kinglets
in the Piedmont, due to unusual weather is simply one possibility.
Some, such as myself may lean to other possibilities, like the one espoused
below.
Robert Prisig noted in one of his novels that the difference between
science and religion was that science comes with an eraser. If someone can
present data or steer me to data that would outweigh the logic posited
below, I would be happy to use my well-worn eraser.
Namaste`
Don Hendershot
Waynesville, NC
-----Original Message-----
From: Bruce Peterjohn [SMTP:Bruce_Peterjohn@usgs.gov]
Sent: Monday, March 06, 2000 1:26 PM
To: donh@asap-com.com
Cc: Jeff Hatfield
Subject: Re: effects of winter storm on kinglet populations
Don:
I have a few comments to add to the earlier message from Jeff Hatfield.
Even if your winter counts of kinglet numbers show a sharp decline after
the storm, it may not be the result of mortality. Some of our wintering
species, such as juncos, kinglets, and yellow-rumped warblers, are known to
be facultative migrants during the winter period. Hence, they have the
ability to migrate away from areas where food is no longer available to
other locations where (hopefully) they can find some food. Lower counts
could reflect these factultative movements, rather than mortality. You
might have to wait until this summer and look at breeding population levels
to have a better idea of whether the current shortage of kinglets may have
resulted from mortality rather than migration. Breeding Bird Survey (BBS)
data may provide an insight into this question, but unfortunately, the
breeding range of both kinglets extends well into the boreal forests of
Canada where there are few BBS routes to indicate breeding population
trends.
Since kinglets glean their food from the branches of trees, I doubt that
the large accumulation of snow would bother them too much. On the other
hand, ice storms, especially persistent ice, could pose some major problems
for wintering kinglets and other gleaners (creepers, woodpeckers, etc...)
Golden-crowneds seem to be more tolerant of cold temperatures than
Ruby-crowneds (based on their winter ranges). By themselves, single digit
temperatures should not bother Golden-crowneds much but could be a problem
for Ruby-crowneds. A combination of prolonged ice and cold temperatures
could be potentially lethal for both species, however.
Hopefully this breeding season will provide some answers. Kinglets have a
high reproductive output, so even if their numbers were decimated by the
winter storms, their populations should recover fairly quickly.
Bruce Peterjohn
USGS Patuxent Wildlife Research Center