South Texas Wildlife, Volume 15, Number 3, Fall 2011 Page: 3
4 p. ; col. ill. : 28 cm.View a full description of this periodical.
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Dr. David Wester is our second
addition, hired in summer 2011 as
a Research Scientist specializing
in quantitative ecology and Profes-
sor in the Department of Animal,
Rangeland, and Wildlife Sciences
at TAMUK. As many of you may
know, David was formerly from
Texas Tech University, where he
served as a faculty member in the
Department of Natural ResourcesManagement for
David was
born in Denver,
Colorado. A
strong inter-
est in natural
resources took
him to Colo-
rado State Uni-
versity where
he majored
in Range and
Forest Man-
agement as an
undergraduate.28 years.
Dr. David Wester is
one of CKWRI's new
Research Scientists
that is specializing in
quantitative ecology.His graduate work was completed at
Texas Tech University. He studied
how patterns of rainfall affect range-
land seeding success in his Master's
thesis. His Ph.D. research investi-
gated the effectiveness of various
quantitative techniques used to
describe patterns in natural veg-
etation in Guadalupe Mountains
National Park.
David's research interests
involve all aspects of plant ecol-
ogy. He also provides guidance for
CKWRI colleagues and students
in designing research studies and
analyzing data. ~Consider giving a tax-deductible
donation to CKWRIAVIAN BREEDING IN ARID
ENVIRONMENTS
by Ian Trewella and
Fidel Hernandez
Birds have evolved to breed
during periods that are favorable
for raising their young. The timing
of breeding, however, depends on
the environment and varies greatly
among bird species. For example,
White-crowned Sparrows breeding
in the subarctic initiate breeding
when day length (photoperiod)
increases and temperatures warm
up in the spring, whereas Rufous-
winged Sparrows in the Sonoroan
Desert wait to initiate breeding until
after summer rains. This variabil-
ity in timing of breeding raises the
question, how exactly do birds know
when to initiate breeding?
In relatively predictable envi-
ronments, birds rely heavily on day
length as a predictor of upcoming
favorable conditions. Temperate
and Arctic ecosystems are some
examples of these predictable envi-
ronments. In these ecosystems,
favorable breeding conditions arise
at approximately the same time
every year. As photoperiod increases
during the spring time, these sea-
sonal breeders increase the size of
their gonads and initiate breeding.
In less predictable environments
such as deserts, photoperiod may
not be a reliable indicator of opti-
mal breeding conditions. Optimal
conditions in these regions generally
follow rainfall, which can be erratic
and unpredictable. Thus, the breed-
Ed tor's Note: Mr. Ian Trewella is a M S. student
at the CKWRI and Dr. Fidel Herrnndez holds the
Alfred C. Glassell, Jr., Endowed Professorship for
Quail Research at CKWRI and Professor in the
Department of Animal, Rangeland, and Wildlife
Sciences at Texas A&M University-Kingsville.Did You Know?
Birdwatching ranks just below camping and fishing as one of
America's favorite pastimes. (U.S. Fish and Wildlife Service)
Black bears have 5 nonretractable claws on each of their paws.
(U.S. Fish and Wildlife Service, Wildlife Biologue, American Black Bear)
3ing of many desert birds often is
highly correlated with rainfall.
Traditionally, increases in food
supply and other materialized effects
of rainfall were thought to explain
the positive relationship observed
between breeding activity and rain-
fall in arid environments. Evidence
exists, however, that some avian
species may take a direct cue from
rainfall itself.
In Australian deserts, Zebra
Finches have been documented to
initiate breeding activity during or
immediately following a rain storm,
regardless of the season. To breed
opportunistically, Zebra Finches are
thought to maintain their reproduc-
tive organs at a semi-developed
state year-round. This is different
from many other bird species, which
reduce their gonad size during the
non-breeding season to reduce
energy costs.
Other avian species around the
globe have a similar response to
rainfall. The Vermilion Flycatcher,
a species found in South Texas, has
C Hugh Lieck
Northern Bobwhite breeding activity
appears to be strongly influenced by the
timing of rainfall events in South Texas.
been documented to engage in nest
building and egg laying within days
of a rainstorm in western Ecuador.
If species are using rainfall as
a predictive cue, then rainfall may
allow them to synchronize the
hatching of their young with the
abundance in food resulting from
rain storms. If they waited for
increasing food resources to appear
before initiating breeding following
rainfall, then hatching of the young
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Caesar Kleberg Wildlife Research Institute. South Texas Wildlife, Volume 15, Number 3, Fall 2011, periodical, Autumn 2011; Kingsville, Texas. (https://texashistory.unt.edu/ark:/67531/metapth578881/m1/3/: accessed May 31, 2024), University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu; crediting UNT Libraries Government Documents Department.