[CT Birds] Cuckoo for cuckoos - a long response...

David Provencher davidprovencher at sbcglobal.net
Sat Oct 8 07:49:42 EDT 2011

For many years I worked a rotating shift at Millstone Power Station. I
became a birder during this tour of duty and I learned about nocturnal
migration and how to predict big flight nights. Millstone Station is lit up
pretty dramatically at night for security reasons. These lights are low to
the ground, not high on buildings or towers. During big migration nights,
when I had to work nights, I would go out and walk the site. I had many
fascinating experiences regarding the nocturnal migrants and some seem to be
relevant to your observations Greg.

One of the things I observed during flight nights were the effects the
lights of Millstone had on the nocturnal migrants. Millstone Station is
located coastally as well so there was a concentrating navigational effect
that The Republican-American does not have (other than the masterful writing
of the staff gathering readers!). On big flight nights the sky over
Millstone would be full of the contact calls of birds. You would have to
experience this to understand the awe the spectacle it engendered. On some
nights it wasn't identifying the calls that was the biggest problem, it was
separating the individual calls from within the myriad of calls happening

Being a coastal location means Millstone Point is what is called a "leading
edge" or "handrail" to navigation. I won't get into the mechanics here but
suffice it to say the migrants would make navigational corrections at such a
landmark. But I noticed that the lights seemed to also have an attractive if
not hypnotic effect on the migrants. The flyers would drop down lower and
swirl around the station within the upper corona of the dull night ground
star that the station's light created. Even to the point that some of the
more terrestrial of flyers, such as Woodcock, Sparrows, or even warblers
like Common Yellowthroat, would fly just above ground level through the
pathways and manmade canyons of the stations structures. Many of these
migrants would be spent from their long draining flights. I once found a
female Black-throated Blue Warbler asleep on the paved ground in the wee
hours on the night. I picked her up to move her to a safer place. I expected
the bird to startle and fly off at being handled. Instead she barely opened
her eyes and gripped my hand tightly with her feet, closed her eyes,
resettled her feathers and went back to sleep. These movements were crisp,
natural, and comfortable, the movement of a bird slightly disturbed from
deep rest, not the foggy actions of a bird suffering from a structure

The swirling cloud of migrants always thrilled me. I even pulled nonbirder,
non environmentally interested coworkers out into the yard to show them the
phenomena. These blue-collar energy industry workers were first patiently
annoyed and then mouth-openingly astounded at the sight as well. One time I
even observed a low circling, calling, Chuck-wills-widow which looked
ghostly pale in the artificial light. And apropos to your post, I saw an
occasional Cuckoo orbiting the site as well. It is difficult to imagine an
easier target for an avian hunter than these tired birds at a navigational
leading edge who were lit up in the orb of light they were drawn into.
Millstone Station now has nesting Peregrines (they weren't there when I
worked nights) and it is relatively easy to find the corpses of their meals.
I have never found a corpse that would be so indicative of nocturnal hunting
as a cuckoo. It should be stated that Cuckoos are unlikely to be flying in
the gloaming. Nocturnal migrants usually launched after the gloaming and
land prior to dawn. They do undergo "morning flight" however, so it is
conceivable they were snagged in the early daylight. But my experience with
morning flight is that the birds climb fast and fairly high during the
flight and they are very aware of their surroundings, much more difficult
prey to catch than the slow flying light-dazzled migrants in the night.

I can easily believe the Peregrines of Waterbury have learned to take
advantage of the opportunity the nocturnal migration coupled with the effect
light pollution affords. If you watch any raptor nest webcam at night (that
is located within an urban area) you will see that these birds do not sleep
soundly and uninterruptedly throughout the night. A hungry hunter is always
stimulated into a high level of sense awareness when presented with a
opportune meal. I rather think these Peregrines have learned to work the
night shift during migration. They may be in very real sense "moonlighting."


Dave Provencher

Naturally New England
-----Original Message-----
From: ctbirds-bounces at lists.ctbirding.org
[mailto:ctbirds-bounces at lists.ctbirding.org] On Behalf Of Greg Hanisek
Sent: Friday, October 07, 2011 4:23 PM
To: ctbirds at lists.ctbirding.org
Subject: [CT Birds] Peregrine: Cuckoo for cuckoos

Peregrine Falcons periodically use the clock tower at my work, the
Republican-American newspaper in Waterbury, as a perch and place for
dismembering prey. Colleagues who work in other departments occasionally
draw my attention to avian bodies or body parts below the tower (which is
visible from I-84).

Earlier this week I was escorted down to an especially ambitious bit of
carnage - a decapitated Blue Jay, a Yellow-shafterd Flicker with its throat
gouged; a pretty much intact Scarlet Tanager; and the head and tail of a
Yellow-billed Cuckoo, which had clearly been dead a bit longer than the
other three.

Up until now the most interesting find over the years had been several
American Woodcock heads, which always caught the eye of non-birders as
especially bizarre. I think the woodcocks were trumped about 15 minutes ago,
when I was led down to see the fresh remains of two more Yellow-billed
Cuckoos - a severed head and whole bird with some of its entrails eaten.

I'm sure it will strike most of you as odd, as it did me, that a Peregrine
could come up with three of a pretty scarce and shy species in such short
order. I wonder if the woodcocks suggest an answer. They most likely were
gottern in the gloaming - dawn or dusk, if not later at night (ask Frank
Gallo about a Peregrine catching moths in a floodlight). It seems to me a
cuckoo, a nocturnal migrant, would be much easier for a Peregrine to snatch
out of the air than to find in the thick cover they usually haunt during
day. In the air, in fact, cuckoos don't seem to be especially fast or
maneuverable. They certainly aren't a bird you see out flying around in the
open, but they're out there under cover of darkness (or near darkness)
during migration.

Greg Hanisek

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