Austin
College
Department of Biology
Student Research
in Ornithology
Devin Trousdale
B.A., Austin College, 1995
Interpretation of Low Contrast Photoperiods
by Japanese Quail. (Independent Study, Fall 1995)
Devin conducted two experiments to
determine whether quail interpret low contrast levels of light as one single
24 hour block of daylight or whether they perceive the light as a distinct
day-night cycle. Birds use daylength to time their reproductive cycles.
In male quail, long days/short nights cause the growth of all reproductive
organs, thus the cloacal protrusion area (CPA) increases. In Devin's experiments,
both high and low contrast photoperiods were interpreted as constant daylight
with the resulting CPA enlargement. These results point to absolute light
intensity being more important than photophase contrast at low levels of
light.
Devin is currently in medical school
following a one year Watson Fellowship in Central America.
Elliott Carman
B.A., Austin College, 1996
Thermoregulation and Metabolism
in Zebra Finches. (Directed Study, January 1995)
Elliott investigated the metabolic
response of adult Zebra Finches to a range of temperatures. Oxygen consumption
was used as an indirect measurement of heat produced by the bird to maintain
its body temperature. As ambient temperature dropped below 25ºC, the
finches increased their metabolism. The one male studied had significantly
lower metabolism than the three females. The difference is thought to be
due to the energetic demands of egg laying.
Thermoregulatory Ability in Neonatal
Japanese Quail. (Independent Study, Spring 1996)
Elliott's experiment studied the body
temperature response of quail chicks to a moderate cold stress (25ºC).
Neonates of both mammals and birds are essentially ectothermic at birth
or hatch. At some time in the neonatal period the young become endothermic
and are able to regulate their body temperatures. Elliott attempted to
determine whether mass or age was a better indicator of thermoregulatory
ability in quail neonates. It was not until eight days of age that the
chicks were able to regulate at 80% of adult ability. Using regression
analysis, mass was found to be a better predictor; however, mass and age
are themselves tightly correlated.
Elliott is currently working for
an environmental consulting firm after completing his Master's degree.
Angela McMellen
B.A., Austin College, 1997
The Effects of Thyroid Suppression
on the Development of Thermoregulation in Neonatal Japanese Quail. (Directed
Study, Fall 1996)
Angela compared the thermoregulatory
ability of quail chicks given propylthiouracil, a thyroid suppressant,
to that of normal chicks. Thyroid hormone has long been known to affect
metabolism and, thereby, heat production. The suppressant was found to
cause lethargy, to retard feather growth, and to slow overall growth in
body mass. Despite these effects, the body temperature response to a moderate
cold stress (25ºC) was not significantly different between the chicks
on propylthiouracil and the normal chicks.
Angela is currently in graduate
school at Michigan State University.
Juliana Lobrecht
B.A., Austin College, 1998
Comparative Study of Avian Usage
of Microhabitats. (Directed Study, January 1996)
Julie studied the effects of climatic
variables, such as ambient temperature, wind speed, and cloud cover, and
vegetation on microhabitat utilization by birds. Six study sites were selected,
each with a different plant community. All sites were within a total area
of 0.1 km2. The most birds were seen when wind speed
was low (<0.05 m/sec.). No trend could be observed for ambient temperature.
Two of the sites averaged more birds over all days counted. This preference
was thought to be a function of vegetation and not climate.
Julie is currentlyRecycling and
Conservation Coordinator for the City of Plano.
Stuart Borrett
B.A., Austin College, 1997
Dual Interpretation of Low Intensity
Light by Japanese Quail.
The Effect of Continuous Release
Melatonin on Reproduction in Japanese Quail.
(Research Assistantship, Summer
1996)
Stuart completed two investigations
into reproduction in quail. The first dealt with how low levels of light
affect the growth of the male reproductive system. Levels as dim as one
lux can be interpreted as either day time or night time, depending on the
intensity of the alternating period. When paired with bright light, the
dim light is considered day time, and the quail is photostimulated. When
paired with darkness, the dim light is interpreted as night time, and the
quail is not photostimulated. The second investigation used melatonin implants
to determine whether the photostimulatory effect of night interruption
lighting could be blocked by melatonin. Melatonin was ineffective in preventing
photostimulation. This brings into question the role of melatonin in the
regulation of annual reproductive cycles in birds.
Stuart is currently working on his
doctorate at the University of Georgia.
Shane Hall
B.A., Austin College, 1999
The Effects of Thyroid Inhibition
on Thermoregulation at Decreasing Temperatures in Neonatal Japanese Quail.
(Research Assistantship, Summer 1997)
Shane continued the work of Angela
McMellen by again comparing the thermoregulatory of quial chicks given
propylthiouracil to that of normal chicks. This time the environmental
temperature for the 20 min. cold stress was lowered to 22ºC after
7 days and to 19ºC after 14 days to match the 3ºC decrease each
week after hatch in the normal brooding temperature. Thermoregulatory ability
of the thyroid inhibited chicks did not differ significantly from that
of the normal chicks over the first 16 days. On day 17 the cold stress
was lowered to 15ºC without a decrease in brooding temperature. A
significant difference in thermoregulatory ability was observed. The previous
cold stress was not sufficient to exceed the thyroid inhibited chicks'
metabolic heat production capability.
Shane is an emergency room scribe
after completing his major in Biology.
Jason Wallace
B.A., Austin College, 1998
The Influence of Photic Contrast
on the Photosexual Response in Japanese Quail.
(McCarley Research Award, Summer
1997)
Building upon the studies of Devin
Trousdale and Stuart Borrett, Jason investigated the ability of Japanese
Quail to differentiate night from day for the onset of the breeding season.
Four groups of male quail were exposed to 8 hour "days" of dim light of
1000, 200, 100, and 15 lux respectively. All groups had 16 hour "nights"
of 1 lux. The 1000 lux day quail could differentiate between day and night,
resulting in no growth of their reproductive organs. The 15 lux day quail
could not tell the difference between day and night and were photostimulated.
With 100 lux or 200 lux days, approximately half of the quail were photostimulated
and the other half were not. Research will continue at the intermediate
light intensities.
The Effects of Composition and Location
on the Seasonal Utilization of Brush Piles by Birds and Other Wildlife.
(Senior Honor's Thesis, Spring 1998)
Jason investigated how wildlife use
brush piles produced as part of land clearing by ranchers and other landowners.
He constructed brush piles of either cedar boughs or deciduous material.
The cedar piles provide a more dense surface, which may allow some animals
to shelter from the weather more easily. Because the deciduous piles are
more open, they may be better for nesting and predator avoidance. Hopefully,
conclusions from this study will be incorporated into recommendations regarding
the building and burning of brush piles in North Central Texas.
Jason is currently in the University
of Texas School of Public Health at UT-Southwestern.
Chad Thompson
B.A., Austin College, 2000 (expected)
Effects of Light Intensity and Sound
on Reproduction in Japanese Quail.
(McCarley Research Award, Summer
1998)
Chad continued studies of the effect
of light intensity on reproduction in Japanese Quail. He found that male
quail are able to discern the difference between light treatments of 400
lux and 1 lux, but half of them were not able to tell the difference between
50 lux and 1 lux. This greatly increases the range over which quail are
known to be stimulated by dim light. Chad also initiated a new line of
investigation, whether sound can replace light as a cue for seasonal stimulation.
One trial with male crow sounds applied during the evening failed to stimulate
other male birds. However, a few males were stimulated when female sounds
were used instead. Future trials should determine the efficacy of sonic
stimulation and characterize the best sounds to use.
Chad is currently a senior majoring
in Biology with a minor in Environmental Studies.
Rhome Hughes
B.A., Austin College, 1998
Avian and Other Vertebrate Diversity
at the Austin College Barry Buckner Preserve.
(Buckner Biology Scholar Award,
Summer 1998)
With the acquisition of the Barry Buckner
Preserve in 1995 the College gained an important piece of North Central
Texas. The Preserve contains many varied habitats: riparian, pine forest,
oak woodland, and open meadow. In preparation for future ecological studies,
Rhome completed an initial database of the avian species diversity on the
Preserve. Rhome observed over 47 bird species, including the first records
for Grayson County of nesting Cooper's Hawks and Pine Warblers. In addition
to birds, the other vertebrate species observed were 6 mammals, 3 reptiles,
and 2 amphibians. One of the amphibian species, the Red Eft (a type of
newt), has never been observed west of the Piney Woods. Further research
on the natural history of the newt continues.
Rhome is currently in theTexas A&M
School of Veterinary Medicine.