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Comments on trends - re Jordan Lake CBC
- To: "carolinabirds@acpub.duke.edu" <carolinabirds@acpub.duke.edu>
- Subject: Comments on trends - re Jordan Lake CBC
- From: Harry LeGrand <Harry.LeGrand@ncmail.net>
- Date: Thu, 11 Jan 2001 08:58:27 -0500
- Sender: carolinabirds-owner@acpub.duke.edu
I greatly enjoyed Norm Budnitz's comments on the Jordan Lake count,
particularly seeing what species were found in record numbers and what
were missed. It's hard to fathom some of those misses with 24 or so
parties! Bobwhite??
Some of the record numbers are probably just a matter of the increasing
number of observers and party hours, such as for kinglets. There aren't
any more kinglets or Pine Warblers around this winter than in most
winters; I'm afield often this winter in the local area, so the high
numbers are due to the high amount of coverage.
But -- the high numbers of Hooded Mergansers are most interesting. There
have been many reports of very high numbers of Hoodeds from across the
Carolinas this winter, and the past few winters. Something IS going on
here. I have notied how numerous it is from coastal impoundments such as
at Pea Island, to Lake Phelps, to some of the borrow ponds along US 64
east of Raleigh, to some of the Triangle lakes (Lake Crabtree, etc.).
They presumably have been undergoing a population increase globally,
though I haven't seen data on this. I don't think it is simply more here
this winter because of cold weather up north freezing over lakes (or
else we'd be seeing lots more Com. Mergansers and Com. Goldeneyes).
The good numbers of Ruby-crowned Kinglets show that small birds such as
this can rebound in a year after heavy local losses. It was clear that
3-4 very severe weeks last winter, with much snow and ice, decimated RCK
locally. But, surviving birds bred successfully up North, plus one can
assume that many or most of the RCK we have in the area this winter
might be young of the year (I'll bet we have a higher % of 1st-winter
birds this year than usual, as many of the would-be adults did not
survive last winter). Of course, without banding, this cannot be known,
and the fact that first winter birds look the same as adults (unlike
with Purple Finches, Baltimore Orioles, etc.) make this impossible to
know as well. But -- at least, the normal number of RCK (and Winter
Wrens) are back now.
The N. Bobwhite continues to become harder to find. Of course, in winter
the birds gather into covers of 10-15 birds each, and do not call except
at dawn or dusk, when some contact calls can be heard on calm mornings
and evenings. They must be flushed by accidentally stumbling onto a
covey along a woodland edge, thicket, etc. The usual culprit one hears
about them is "habitat loss". Of course, that is partly true, as many
old-field birds are indeed declining, such as Field Sparrow. But is that
really the main problem? Other old-field birds are doing well, such as
Blue Grosbeak, or are holding about steady, such as Prairie Warbler and
Y-b Chat. I have conducted a BBS route for 30 years in remote Warren
County, where clearcuts are widespread. These grow up in a decade, but
others appear, as a matrix of early succession, pine thickets, pine
forests, etc. The Bobwhite, despite being completely non-migratory, has
shown a STEEP decline on my route. But, the habitat has stayed the same
to my eyes -- Field Sparrows way down, but the warblers and Grosbeak no
change. Simply put, the decline of the Bobwhite has be very widespread,
over most all of the eastern US, over all counties, etc. The decline
does not SEEM to be patchy, which would be the case if habitat decline
were the major factor, as habitat problems are very spotty. What could
be the primary culprits? Severe winters killing birds or snow
smothering food; diseases; great increase in number of predators such as
raccoons, opossums, and possibly hawks. I am a believer that the great
increase in predators such as raccoon and opossum could be a factor, as
they would prey on eggs or young of the birds, as they are ground
nesters. Of course, there are plenty of other ground nesting birds not
showing declines, so -- who knows? Whatever, the decline of the Bobwhite
is not simply "habitat loss" and is really more of a broad-scale
concern. (The wildlife emphasis to work with farmers to provide better
habitat -- more hedgerows, more brushpiles, less tidy farming, etc.,
seems like a noble cause, but that isn't going to bring back the
Bobwhite.)
--
Harry LeGrand
NC Natural Heritage Program
1615 MSC
Raleigh, NC 27699-1615
(919) 715-8687 (work)
FAX: 919-715-3085
e-mail: harry.legrand@ncmail.net