[Birdtalk] nocturnal birding

[L. D. Giddings]

The following was posted on yesterday's Colorado list by Ted Floyd,
editor of "Birding" magazine. It is a bit lengthy and may generate some
discussion, hopefully of the friendly variety. Those of you with good
ears and the ability to remember call notes may find it especially
interesting. I would also urge you, if interested, to follow this link
http://lists.envirolink.org/pipermail/ohio-birds/2006-May/011838.html in
which a further discussion of monitoring night migrations by ear is
discussed.

Lu Giddings

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Subject: Nocturnal migration: Lafayette, Boulder County, 30 August 2006
From: "Ted Floyd" <tedfloyd at aba.org>
Date: Wed, 30 Aug 2006 14:58:37 -0600
X-Message-Number: 4

Hello, birders.

After several exceedingly slow nights, the nocturnal migration over
Boulder County was decent earlier today, Wednesday, 30 August 2006. I
heard at least 20 flight calls over our house in Lafayette between 3:30
and 4:00 this morning. No particular species dominated, and all calls
were of the short-duration high-frequency variety: a few Yellow
Warblers, a few calls that I conjectured to be Townsend's, a few
presumed MacGillivray's, at least 2 Wilson's, only 1 call that sounded
like Chipping Sparrow, and the usual array of indeterminate
sparrow/warbler notes. Not even remotely close to the drama of last
Friday morning, 25 August 2006
<http://lists.cfo-link.org:8080/read/messages?id=3D337518>, but better
than the intervening days.

Speaking of which...

* Saturday morning, 26 August 2006, at Walden Ponds, Boulder County, in
the light rain, was more or less a bust, in terms of nocturnal
migration. One interesting note though: The one *and only* nocturnal
migrant that I heard was a lone Eastern Kingbird, migrating over from
north to south, calling sharply as it went, just before 5am. That's
interesting because flycatchers in general, and Eastern Kingbirds in
particular, are not "supposed" to call on nocturnal migration. But this
bird certainly was vocal. For more perspective on nocturnal migration by

Eastern Kingbirds in Colorado, check out
<http://lists.cfo-link.org:8080/read/messages?id=3D334758>. Also nice at

Walden, in the daylight hours, was hearing a Northern Waterthrush give
its fairly distinctive flight call: of long duration (that's relative;
long for a warbler), buzzy, and generally "rich"-sounding.

* Sunday morning, 27 August 2006, at Doudy Draw, Boulder County, under
lovely starlit skies (Venus and Saturn, just 4.3 arcminutes apart, were
a nice touch), was also a bust. A few birds were on the move, but very
high up--so high up that I couldn't get any real detail on the
vocalizations; just chalk 'em up as sparrows/warblers, I guess. During
the early-daylight hours, though, I was pleased to encounter large
flocks of Spizella sparrows (many Chipping and Brewer's Sparrows, a few
Clay-colored Sparrows), with many of them giving flight calls
repeatedly. I got great studies of calling Brewer's and Chipping
Sparrows, and would like to venture a few very tentative, very
provisional, points of distinction between the two species. First, their

flight calls are similar! But I believe I was getting on some consistent

differences: The calls of the Brewer's Sparrows seem more even-frequency

(not rising as sharply), with slightly more of a buzz (more modulated),
and a hard to quantify, slightly piercing quality about them; in
contrast, the calls of Clay-colored Sparrows seem to rise more sharptly,

to be purer in tone, and to have a more tinkling/ringing than piercing
quality about them. I will be the first person to acknowledge that: (a)
these results are preliminary, (b) they are doubtless subject to
distortion given variation in atmospheric conditions, and (c) they
doubtless vary intrinsically somewhat, anyhow. Well, we'll soon get
Nathan and his fabled fuzzy stick on this problem, I hope. Something
else from Doudy Draw: many, many flight calls of Lazuli Buntings and
Blue Grosbeaks, during the early-daylight hours. They're not especially
difficult to distinguish (cf. Clay-colored vs. Brewer's), but they do
make for a nice tutorial for those of us (i.e., pretty much all of us)
who can still benefit, every now and then, from exposure to "easy"
flight calls.

* Monday morning, 28 August 2006, out in the driveway in Lafayette,
nothing but 3 Green-winged Teals flying low over the rooftops. Yes,
sometimes you go outside and hear nothing. Which makes other nights--the

ones that *do* feature nocturnal migration--all the more thrilling. As
Aldo Leopold wrote in his enchanting essay, "The Choral Copse", about
being out early on a September morning: "The disappointment I feel on
those mornings of silence perhaps shows that things hoped for have a
higher value than things assured. The hope of hearing quail [or
nocturnal migrants, if I may] is worth half a dozen
risings-in-the-dark."

* Tuesday morning, 29 August 2006. I actually, ahem, was asleep during
the pre-dawn hours.

Well, lots still to learn, and as Joey Kellner recently reminded us
<http://lists.cfo-link.org:8080/read/messages?id=3D338020>, things are
just getting started.

-------------------------------

Ted Floyd
Editor, Birding

American Birding Association
P. O. Box 7974
Boulder, Colorado 80306-7974

303-444-6363
tedfloyd at aba.org

Please visit the web site of the
American Birding Association:
http://www.americanbirding.org