Bobwhite Quail Decline in Texas
Part of the Young Naturalist Awards Curriculum Collection.
The bobwhite quail, Colinus virginianus, is in the same family as other ground-dwelling fowl such as the pheasant and the grouse. A typical bobwhite quail is approximately six inches tall and weighs only about six ounces. Even though Texas appears to be the last stronghold for quail, their numbers have been declining annually by 4.7 percent across their Texas range. Some theorize that if this trend is not checked, the bobwhite quail will pass into extinction by the year 2005. This would be a terrible blow not only to hunters and wildlife enthusiasts, but also to businesses in rural communities that provide services to those who come to enjoy this small game bird.
I first became interested in quail when I attended the Bobwhite Brigade, a five-day wildlife leadership camp. My assigned "silver bullet" (an inspirational saying) was this quote from Aldo Leopold: "The outstanding scientific discovery of the 20th century is not the television or the radio, but the complexity of the land organism." Thus began my development of a land ethic.
I found that trailing dogs with my grandfather, who has a passion for hunting, provided memorable opportunities to observe the bobwhite quail. Over the past year I have attended several "quail appreciation days" at different locations around the state. I have had the opportunity to visit many ranches, including the famous King Ranch, where I was introduced to many land management and conservation principles. Because of these experiences, I became intrigued with following these principles on our 10,000-acre family ranch. I know that the future of the bobwhite quail rests in the hands of landowners and people like my family and me.
The Texas Quail Index (TQI) is a five-year study that measures certain factors that are known to affect quail populations. It monitors the quail population to assess what changes occur and how they influence the species' population dynamics. In order to do this on a large scale, the coordinator, Dr. Dale Rollins, has enlisted the help of cooperators in 48 counties in Texas. Dr. Rollins will take all the data collected by the cooperators and create one massive database. He will then be one of the primary analysts looking for patterns between the measured factors and local quail population size.
It was my job as one of the cooperators to gather and record the data from our ranch and send it to Dr. Rollins. The TQI evaluated several factors in hopes of predicting not only the causes of quail decline, but also the management strategies needed to reverse it. However, I hypothesized that the most important factor affecting quail population size would be the weather. My reasoning was that before humans were present, weather was the only factor that affected quail abundance. All the other factors depended on the weather as well. Our rainfall totals for the past five years had been below the norm, and our land was depleted of the plant life that is vital to quail survival.
I'm not the only cooperator working in Callahan County. Working with me are my father and mother, Jay and Nancy Capra, and my two sisters, Sarah and Hannah. We enlisted the County Extension Agent, Robert Pritz, for his expertise in plant identification and support. We maintained a rigorous schedule, and followed the protocols and timeline developed by Dr. Rollins. I hope that what follows will give you a taste of my experiences in the field, in pursuit of a bird that I respect and treasure.
The TQI is designed as a series of experiments and surveys that allow us to track certain factors that affect quail. Those factors include weather, forb diversity, nesting site availability, nesting success, breeding intensity, covey numbers, predator density and diversity, and overall quail abundance. I performed these experiments at the same time of the year as the other cooperators. This allowed for continuity in the results across the state. The timeline was developed around the quail's biological cycle during the year. An example would be the spring mating-call counts. The bobwhite rooster only makes this call during the breeding season, which is April through July. Because of parameters like this, the cooperators were busy year-round.
The location where I collected all our data was the Spring Gap Ranch in Callahan County, near Cottonwood, Texas. It was named for the natural springs that the settlers used when they traveled across a portion of the land between two hill ranges known as the gap. The land has been used for cattle ranching and some recreational hunting. My grandfather has always managed the land in a manner that benefits both wildlife and cattle. The terrain consists of rolling hills with many deep draws and canyons. It is covered with a wide diversity of plants, with the major brush species being juniper, scrub oak, live oak, mesquite, and flame leaf sumac. A known flaw in the plant diversity is the tremendous amount of juniper on the ranch. We already employed a skid loader with shears on the front in a year-round effort to take out these water-robbing plants.
I began this project on April 25, 2002, in San Angelo, Texas. It was at this time that both my mother and I went through the cooperator training. This was very important because we were trained in the methods and techniques we would use to perform the surveys and experiments. The protocols were taught in order to sustain scientific integrity. The afternoon was spent in the field, where we learned to identify the key food and cover-plant species necessary for quail to thrive.
I was encouraged and excited to set up our TQI transect on the Spring Gap Ranch. This was probably my most important decision during my experiment because all measurements would be made in its immediate vicinity. The transect was a 10-mile-long line with a marker at the beginning and one at every mile after that. Each mile marker was given a number from zero to 10, to create 11 stations as data collection points. It was important when we set up the trail that we didn't double back too much or cross our lines. I was able to follow roads that already existed on the ranch. Once I had planned where the transect would run, I had to go out and drive T-posts into the ground and set up our mile markers.
On my next trip, I took the GPS location of each marker, habitat photos for baseline illustrations of the land, and forb diversity surveys. For each habitat photo I took a dry-erase board and wrote out the mile marker number and then either L or R (for left or right), depending on which side of the road I was photographing. I then walked out 20 feet from the road and had my mom take my picture with our digital camera. We did this for every station, and then printed out all 22 of the pictures. These were sent to Dr. Rollins in San Angelo so that he could record them. He then appraised each site based on how much he thought the habitat would appeal to quail. Using this data, he assigned our ranch a 4.6, with 10 being the very finest quail habitat. I was not discouraged because I knew our land had suffered from a long-term drought and that the plant life needed time to recover.
To assess the plant species diversity, I used a hula hoop (very scientific!) and randomly tossed it over my shoulder on both sides of the road at every mile marker. After the hoop had come to rest, I recorded the number of different species inside it, as well as the number of each type. I then had to identify each plant, which is where Mr. Pritz really became a big help. While my mother and I knew many of the trees and larger forbs, we were completely lost when it came to grasses. Once all this work was done, we calculated our Species Diversity Score. This was the reason I counted every plant. The score is calculated by dividing the total number of different species by the total number of plants. Our diversity score was 0.96. I was hopeful. We had already gotten 8.98 inches of rain that year. It was looking to be a wetter year.
I performed a population survey by listening to the quail rooster as he crowed his spring mating calls. I would go out in the early morning and spend five minutes at each mile marker, listening for his distinctive poor-bob-white. I would record where I heard various roosters on a distance chart and the number of times I heard the call within a five-minute period. I did this at every mile marker three times between May 1 and June 1. This information gave me an idea of the breeding intensity and the number of roosters located near the transect. I knew that in some areas we had a large number of mating roosters, while at one or two of the markers I heard virtually none at all.
The next big assignment was our dummy nest depredation survey, which we conducted in June. This was an experiment devised to mimic the success of quail nests using simulated nests with chicken eggs instead of quail eggs. This survey corresponded with the quails' natural nesting time. Mr. Pritz's assistance was invaluable, as this project was extremely tedious and difficult. The protocol for this experiment was to draw six numbers randomly from zero to 10. At each of the six mile-marker numbers drawn, we assembled a nest transect. At the designated mile markers, I flipped a coin to decide left or right. This was so that the data would be a random scattering from all over the ranch. Each nest transect consisted of six nests planted at roughly 50-yard intervals on a line perpendicular to the road.
At each interval I tied pieces of flagging tape, choosing either prickly pear cactus or bunch grass depending on whether it was an odd- or even-numbered nest. From the flagging tape I walked to the nearest bunch grass or cactus patch that might qualify as a selected nesting site. I then placed three chicken eggs in what we deemed a nesting site. If there wasn't a good place available, I made one with the toe of my boot. I then faced the flag and counted the number of paces back to it. We recorded a bearing of the direction using a compass and GPS coordinates. This would allow me to locate the nest again if I was unable to remember where it was. It also gave us the flexibility to have another person on the team check the nests even if he or she hadn't helped us set them out.
I checked on the nests once a week for a month. When the nests were monitored the first week, I found that a third of the nests had been destroyed. All six nests at one of the mile markers had been wiped out in the first week. I hypothesized that this was because of some odor we had left on the eggs, because each nest was destroyed by the same species of predator. I knew this because of the way the eggs were broken and consumed. Observation told me that a raccoon probably went down the length of the transect and had an egg buffet. This might have indicated a high quail-egg predation rate except for the scent we probably left on the nests. I had tried to avoid this by wearing rubber gloves and rubber-soled boots. Over the next three weeks I noted a continued drop in nest success. During this time I observed a red-tailed hawk. Every time I checked the nests at mile marker 8, I would see it sitting atop a nearby telephone pole. It would often screech and circle our car when we came over the hill. At the end of the third week, I still had 16 nests out of the original 36. I thought this was great since quail take only 23 days to incubate their eggs. I was unable to investigate the nests during the fourth week because we received 13.01 inches of rain on July 7. This was a flood, and many houses in town were badly damaged, including my great-grandmother's. We had to put the TQI on the back burner for a while as we gutted and rebuilt her house. However, from the data I had gathered, I was able to get an idea of the role that small mammalian predators play in the life of the quail living on our ranch.
A scent station survey was laid out in late July. This would survey predators by appealing to their curiosity and sense of smell. At each of the markers I cleared an area the size of our hula hoop. I then spread a layer of flour about a quarter of an inch thick over the whole surface. Finally, I placed a small scent tablet in the center of the circle. The tablets were given to us at our training session and had the smell of fatty acid. I then checked each station the following morning for two consecutive mornings. I found that, although the dummy nests were heavily predated, the scent stations were almost entirely left alone. This made me think that we must have a small but intelligent predator population on the ranch. Our ranch foreman assured me that there were plenty of varmints on the ranch. I think the enormous amount of recent rain might have provided more food opportunities for all the wildlife.
After the scent stations, I was done with the experiments for a little while. We did go out to the ranch several times for different reasons. On these trips, I began to notice an increase in quail numbers. I also noticed an obvious increase in the diversity and number of forbs. In October I did another forb diversity study and found what I had already guessed to be true. We also conducted a covey call count. This was similar to the spring mating-call counts except that I was listening for a different sound. It was the morning trill that the lead rooster of each covey gives. Other members of the covey respond with the same call. This count also confirmed what I had already begun to observe: the population of quail had gone up. I have seen many good-sized coveys, and wildlife enthusiasts are calling this season the best in 10 years.
I believe these increased numbers correspond with the rainfall we received in midsummer. In June we had 1.79 inches; in July we received 13.01; and in August we were back down to 0.4 inches. This spike in rainfall came at exactly the right time. The chicks were just hatching and beginning to wander with their parents. The rain caused a spike both in the insect population and in the amount of dense ground cover. The main food for quail chicks is small insects like grasshoppers and crickets. The increased plant cover allowed the chicks to move more freely in their pursuit of food, and probably many fewer were taken by predators. This would support my original hypothesis, that the weather would be the dominant factor affecting quail abundance.
My conclusion is the same as my hypothesis. Rain, or the lack thereof, is the primary factor in quail population size. This is supported by the data I collected while in the field and what I observed while hiking. However, because I have only one year's worth of data to go by, I am still unsure of the relationship and how to use rain totals to predict quail numbers. I also determined that the effects of predation are not as great a factor as I once thought. Each of the factors plays a part in the quality of the quail's habitat, but I don't know to what extent. While this year we got rain when we needed it, I have to look ahead and attempt to discover ways to influence the habitat during times when we don't have rain. This will help me to develop a proactive management plan.
Now that I have completed my first year of observations with the Texas Quail Index, I feel that I know our land better and the animals that live there, too. With some time and a lot of work, I hope that some day I can predict quail population trends. However, that's a long way off. Right now I am glad I can enjoy the early-morning call counts and my hunting memories. Hopefully, with what we discover, we will be able to reverse the trend of quail decline and keep those bobwhite coveys flushing.
References
Audubon, John James. The Birds of America. New York: Macmillan Company, 1946.
Bobwhite Basics, n.p.: The Southeast Quail Study Group, 2002.
Kieran, John. An Introduction to Birds. New York: Garden City Books, 1946.
Mattiza, Dorothy Baird. 100 Texas Wildflowers. Tucson: Southwest Parks and Monuments Association, 1993.
Perrins, Christopher. Birds: Their Life, Their Ways, Their World. New York: The Readers Digest Association Inc., 1979.
Peterson, Roger Tory. A Field Guide to the Birds East of the Rockies. Boston: Houghton Mifflin Company, 1980.
"Quail Decline in Texas." TEXNAT, September 29, 2000. Retrieved from the World Wide Web on September 5, 2001: http://texnat.tamu.edu/Decline.htm.
Rollins, Dale. "Sustaining the Quail Wave in the Southern Great Plains." Quail V: Proceedings of the Fifth National Quail Symposium (2002): 48-56.
Rollins, Dale. Texas Quail Index Information Booklet. San Angelo, Texas: 2002.
Stall, Chris. Animal Tracks of Texas. Seattle: The Mountaineers, 1990.
Taylor, Richard B., Jimmy Rutledge, and Joe G. Herrera. A Field Guide to Common South Texas Shrubs. Austin, Texas: Texas Parks and Wildlife Press, 1999.