[Bristol-Birds] Research finds NW Ohio Lark Sparrows migrating thru East Tennessee
- From: "Wallace Coffey" <jwcoffey@xxxxxxxxxx>
- To: "'Bristol Bird Club'" <bristol-birds@xxxxxxxxxxxxx>
- Date: Mon, 21 Jul 2014 14:35:06 -0400
Lark Sparrow Paddle Creek Ponds 20 Sep 2009.JPG
Lark Sparrow atop fence post at Paddle Creek Pond,
eastern Sullivan Co., TN, 20 September 2009. It
was found by Rick Knight (photo by Wallace Coffey).
Researchers carried out "geolocator" work on a tiny Lark Sparrow
population which inhabits a very limited area in NW Ohio at Oak
Openings Preserve Metropark, south of I-90 in Lucas County.
One of the spinoffs of the study for us in Northeast Tennessee is
that three tracked birds shown on maps projected in the study
revealed all three passed through East Tennessee during fall
migration, including several in our neck of the woods. They
start migration about this time of season.
The study was published in Animal Migration, 2014; volume 2, 29-33,
an international journal that publishes cutting-edge research on
the biology of migratory species.
.
The interesting possibility for our region is that, despite the few
Lark Sparrows we encounter, migrant Lark Sparrows seen here
In fall may still be in breeding season plumage while passing thru our
habitats. It appears likely that they do not molt to winter wear
until they reach the "estimated" wintering ranges approximately
corresponding to the southern Warm Desert and Southern Semi-arid
Highlands ecoregions in central Mexico.
Along the way, Lark Sparrows have indirect migration paths and this
small Ohio population comes south into Tennessee and then travels
south of the state and then west to migrate down the Mississippi River.
This delayed timing is called molt-migration behavior. The majority
(about 74%) of "Eastern" songbirds remain on breeding grounds to
undergo feather molt and subsequently make relatively direct
autumn migrations to wintering grounds in winter plumage.
However, it is not yet well established and understood that the
Eastern population of Lark Sparrows actually delays molting until
they reach their wintering grounds which is contrary to what most
Eastern populations of song birds do. The Western population of
Lark Sparrows delay molting until they reach the wintering ground
and that is contrary to what most Eastern North American migrant
species do. But this appears to be what or Eastern migrant
Lark Sparrows are doing.
What the study has carefully documented for us is the migration route
of Eastern Lark Sparrows from NW Ohio moving thru Tennessee
and our area.
Most of us are familiar with the various forms of satellite
tracking of eagles, etc. The tracking of Lark Sparrows uses a far
different but equally fascinating technology.
Ohio researchers carried out what is known as "geolocator" work
when they determined that the tiny Lark Sparrow population in NW Ohio
passed through East Tennessee.
From 2005 to 2011 they monitored a population of Lark Sparrows in
Ohio (i.e., an eastern population) and observed that the species
disappeared relatively early compared to other local, migratory
songbird species (i.e., by August 10), with no flight feather molt
detected among 58 adult and juvenile Lark Sparrows captured there
during July.
To address this question, they used light-level geolocation data
loggers (geolocators) to ascertain migratory timing and routes
of individual Eastern Lark Sparrows breeding in Ohio. The recent
miniaturization of light-level geolocators has rapidly advanced our
understanding of individual variation in migratory life- cycles among
small songbirds.
Although the word 'geolocator' is non-specific, this is often used to
describe a device that primarily and periodically records ambient
light level (solar irradiance) to determine location. A geolocator,
light-level logger, GLS or bird logger is essentially a lightweight,
electronic archival tracking device, usually used to map migration
routes, identify important staging areas, and sometimes provide
additional ecological information.
Geolocators record changes in light levels. The smallest are archival
types that do not use satellite or radio telemetry and recapturing
the bird is necessary to retrieve the device to download the data
to a computer for analysis which estimates maximum migration
likelihood.
Recording light levels over time produces data that can be used
to calculate latitude and longitude readings of a bird's long-distance
movements.
When the Lark Sparrows returned to their breeding grounds in
NW Ohio, they were captured and the data downloaded from the
geolocator and entered in computers to map the birds movements
during migration and over winter as determined by the solar light
the system had measured along the way.
The use of dedicated light level recorders for tracking birds was
pioneered in the 1990s by British engineers and scientists in an
attempt to record the movements of juvenile Wandering Albatross
during the many years between fledging and returning to their
colony to breed. Use of geolocators has been extended to many
other migratory bird species.
Not much is known about Lark Sparrows in our area and we have
few records. In addition to the bird found at Paddle Creek Pond
in September 2009, Mike Poe photographed the first unequivocal
record in Northeast Tennessee just behind Tri-Ciity Airport in Sullivan
County, TN. Tom McNeil found the bird and more than a dozen other
birders showed up to see the bird. The Migrant 76(2):77-84, 2005.
Those observing the 2005 bird were: Tom McNeil, J.T. McNeil, Don Holt,
Diane Draper, Dexter Newman, Lynda Newman, Mike Poe, Rick Knight,
Wallace Coffey, Larry McDaniel, Chris O'Bryan, Janice Martin, Fred Martin
and Ethel Newman
Dee Eiklor had one 25 November 2003 at her home in Gray, Washington
Co., TN.
There are two May records.
We might remain alert for any possibility that a Lark Sparrow encountered
in our area during fall migration or in winter may be in breeding plumage.
Wallace Coffey
Bristol, TN
The researchers and authors of this paper are: Jeremy D. Ross: Oklahoma
Biological Survey, University of Oklahoma, Eli S. Bridge: Oklahoma
Biological
Survey, University of Oklahoma, Mark J. Rozmarynowycz: Department of
Biological Sciences, Bowling Green State University, Verner P. Bingman:
Department of Psychology and Bowling Green State University.
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