Browsing by Subject "Birds -- Texas"
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Item Aspects of the ecology and management of pheasants in the High Plains of Texas(Texas Tech University, 1983-05) Whiteside, Richard WhittingtonNot availableItem Avian behavior in Chinese tallow woodlands and evaluating the potential control and allelopathic interference of Chinese tallow(Texas Tech University, 1997-12) Conway, Warren C.The Chinese tallow tree, (Sapium sebiferum (L)) Roxb.), has been cultivated for over 14 centuries in China for seed oil. Chinese tallow was introduced to the United States in the mid to late 1800s and has since naturalized throughout much of the southern U. S. Tallow invades a wide variety of habitats, including freshwater wetland basins, coastal prairie, mixed bottomland hardwood forests, as well as disturbed sites. It continues to expand throughout the southern U. S., but control efforts have been inconsistent. The mechanisms by which it invades are presently unknown, as are the impacts of this invasion on native biota. Therefore, we need to know how to control future tallow expansion, investigate its ecological impacts, and understand the mechanisms for its success. During 1995 and 1996,1 studied avian behavior in Chinese tallow woodlands and evaluated potential control and allelopathic interference of Chinese tallow in the coastal prairie region of Texas. My objectives were fourfold. First, I determined total nonstructural carbohydrate (TNC) movement in Chinese tallow, and identified the period of downward translocation of photosynthate. I linked that specific physiological stage with a visible phenological stage of development in the annual cycle of tallow to determine optimal timing for control treatments. Second, I evaluated the allelopathic potential of Chinese tallow on seed germination and seedling growth and development of plant species native to the coastal prairie region of Texas. Third, I quantified avian use of and behaviors in Chinese tallow woodlands during fall migration along the Texas coast. Finally, I evaluated avian use of Chinese tallow seeds, by subjecting seeds that were fed upon by birds, to bioassay experiments to test for seed germination enhancement by bird feeding activities. Chinese tallow root TNC trends and phenological development were monitored over an annual cycle. Six phenological stages were recorded; (1) dormancy. (2) bud break, (3) leaf development, (4) seed formation. (5) seed maturation, and (6) leaf fall. Tallow root TNC concentrations varied by phenological stage (P < 0.001), where concentrations were highest (P < 0.05) during leaf fall (60.72%) and lowest (P < 0.05) during leaf development (41.11%) and seed formation (36.71%). Chinese tallow root TNC concentrations increased during the period of seed maturation until leaf fall. If foliar applied herbicides are delivered during this period of downward translocation, effective tallow control should be observed. I performed seed germination bioassays using black willow (Salix nigra), baldcypress (Taxodium distichum), Chinese tallow, and lettuce as test species in 2 different experimental media (i.e., aqueous extracts and substrates) prepared from fresh tallow leaves, fallen litter, and tallow woodland soil collected during 4 months to evaluate seasonal differences in allelopathic interference potential. Distilled water was used as a control for aqueous extract treatments, whereas air-dried peat was used as a control for the substrate treatments. There were varied responses by black willow, baldcypress, and lettuce seeds and seedlings exposed to tallow extract and substrate treatments. In some instances, test seeds experienced enhanced (P < 0.05) seed germination and seedling growth, but in others these responses were reduced. When exposed to its own extracts and substrate treatments. Chinese tallow showed more consistent responses. Chinese tallow control (i.e.. distilled water and substrate) treatments had reduced (P < 0.05) seed germination and seedling growth as compared to control treatments. These data suggest that tallow is not autotoxic. Tallow seed germination and seedling growth and development maybe enhanced when exposed to its own leaves, litter, and soil. Chromatographic analyses performed on the aqueous extracts support these data. No potential allelochemicals were detected during gas chromatography/mass spectrophotometry analyses. The only chemical detected during these analyses was inositol- a naturally occurring a cyclohexanehexanol. Therefore, successful tallow invasion is likely enhanced through mechanisms other than allelopathy. Time-activity budgets were developed for black-and-white (Mniotilta varia) and yellow-rumped (Dendroica coronata) warblers. Feeding, resting, moving, maintenance, searching for food, calling while perched, and moving and calling behaviors were quantified. During 1995 and 1996, searching for food was the predominant (56.48%) activity for black-and-white warblers, whereas resting (55.89%) was the predominant activity for yellow-rumped warblers. Behavior data were also determined for other migrant, permanent resident, and winter resident birds. Migrants were observed feeding or searching for food more (P < 0.05) than either permanent or winter resident birds. These data support the hypothesis that migrant birds allocate more time to feeding and searching for food than either permanent or w inter residents birds. I collected Chinese tallow seeds that had been fed upon by yellow-rumped warblers during 1995 and subjected them to seed germination bioassays. No differences (P > 0.05) were observed for percent germination between seeds fed upon by yellow-rumped warblers (2.5%) and seed that were collected directly from Chinese tallow trees (2.5%). Bird feeding activities do not enhance tallow seed germination, but birds may still influence future tallow expansion through seed dispersal.Item Nesting of ring-necked pheasants in the Texas Panhandle(Texas Tech University, 1980-12) Taylor, Tim ThomasNesting studies of the ring-necked pheasant (Phasianus oolchicus) were conducted during 1979 and 1980 on 3 study areas in Castro County, Texas. Playa basins had higher density of nests (2.21/ha) and greater production of chicks (8.37/ha) than wheat, alfalfa, roadside/strip, oat, and rye habitats. Nest initiation began on approximately 23 March and continued through 13 July. Peak nesting activity occurred from 29 April to 4 May and 23 to 28 May during both years. Similarity of nesting phenology between the Texas Panhandle and northem pheasant range suggested consistent nesting behavior over a wide latitudinal distribution. Young were produced in 24% of the nests (N = 221). Harvesting, predators, abandonment, and flooding contributed to 32, 21, 15, and 5% of the nest losses, respectively. Larger clutch sizes in playas, alfalfa, and oats were attributed to early nest initiation in these habitats relative to rye and wheat fields. The respective mean weight, volume, and eggshell thickness for both years was 26.3 ± 0.18 g, 26.3 ± 0.13 ml, and 0.256 ± 0.001 mm. There was an unexplained difference in eggshell thickness between habitat types with alfalfa, wheat, and roadside/strips having a greater (P < 0.05) thickness than playas, oats, and rye fields. The mean fertility rate was 93.0 ± 0.0"% for eggs in successful nests. Playa basins and roadside/strip cover were the most promising habitat types available for management of nesting cover in the Texas Panhandle.Item Recruitment of black-bellied whistling-ducks in South Texas with special reference to the use of nest boxes(Texas Tech University, 1987-08) O'Kelley, Brian LeeIn light of an increasing population of black-bellied whistling-ducks and associated nest-box numbers, a study was conducted to measure the contribution of young produced in nest boxes to total production at key breeding areas in south Texas. Nest boxes at five locations throughout south Texas was monitored for two nesting seasons to determine the effect, if any, on production. Although nesting effort was high, rate of nest loss and measurements of the contribution of box-produced young indicated poor performance from nest boxes. A total of 8084 eggs in 266 nests resulted in 79 successful nests yielding 1395 hatchlings. Poor hatching rates, high progressive brood mortality and large numbers of young produced from other kinds of nests (e.g., ground nests) reduced the significance of nest boxes as a management tool. The annual recruitment rate from nesting in boxes was estimated at 1.75-1.99 young per nesting pair. Brood surveys conducted at nest-box study areas did not yield brood densities higher than densities at the headwaters of Lake Corpus Christi, an area without nest boxes. The data indicated that proper predator deterrents, reduced competition for nest boxes, and proper density and location of boxes can increase the efficiency of a boxmanagement program. Concentrations of black-bellied whistling-ducks were monitored following the nesting season to examine the social structure of flocks. Feeding ducks were observed at bait sites to determine if whistling-duck family units, unpaired adults, and orphaned fledglings arrive at, and approach, bait differentially. Age ratios of feeding birds changed dramatically as the "time on bait" progressed. The proportion of young in the feeding group was greatest at the onset of feeding activities (x = 75% juveniles). Four rocket-net captures showed similar changes in age ratios (i.e., as "time on bait" increased, the percentage of juveniles in the samples decreased). Family units most often arrived at bail first and defended the feeding area against other arriving birds. Juvenile black-bellied whistling-ducks captured with rocket nets showed a slight preponderance of females but did not differ (p > 0.05) from a 50:50 ratio.Item Response of bobwhites to habitat management in the Rolling Plains of Texas(Texas Tech University, 1981-05) Webb, William MEffects of habitat management on bobwhites (Colinus virginianus) were studied from June 1978 through May 1980 in mesquite (Prosopis glandulosa) and sand shinnery oak (Quercus havardii) communities. Management in the mesquite community included spring disking of strips, half-cutting mesquite, and construction of "teepee" style brush piles and livestock exclosures which contained a brush pile. Strips were disked in 2 4-ha exclosures in the sand shinnery oak community. Disking increased (P < 0.05) canopy coverage and distribution of important seed-producing forbs in both communities. Coverage of 10 selected forbs in the mesquite area strips was increased by 171.0 and 77.1% during 1978 and 1979, respectively, while coverage of 6 selected grasses was decreased by 31.5 and 57.3%. Coverage of 9 selected forbs in the sand shinnery oak strips increased 214.0 and 728.0% during 1978 and 1979, respectively, while coverage of 6 selected grasses decreased 80.7 and 62.4%. Sand shinnery oak coverage was 84.0% lower on the disked strips during each year. Bobwhite numbers increased in the managed areas of each habitat. More birds were trapped each month in the managed areas and a large percentage were new captures, which indicated that intense management in mesquite and sand shinnery oak habitats increased ingress of bobwhites and an area's ability to support more birds, even through drought. No significant differences (P > 0.05) were detected in weights of bobwhites between managed and control areas. No definite trends existed for month-to-month survivorship but data from the mesquite areas indicated better survivorship in the managed area during both trapping seasons. Survivorship in the sand shinnery oak areas was similar during both years. Habitat improvement in the mesquite area cost $6.20 and $11.64/bird during 1978 and 1979, respectively. Costs/ha were $7.22 and $10.86 during 1978 and 1979, respectively.Item Some aspects of the winter ecology of harriers on the Texas High Plains(Texas Tech University, 1981-08) Schibler, Michael DPlaya basins (marshy, seasonal lakes) are the primary wintering habitat for Northern Harriers (Circus cyaneus) on the Southern High Plains of the Texas Panhandle, The harrier population is predominantly juvenile. The sex ratio within the first-winter age class was 2.86:1, and, although not statistically significant (.1 < P < .5), was accepted as representative of the age class. First-winter harriers used playas more than fields. Playas associated with agriculture were preferred over those associated with rangeland, and playas with vegetation taller than 1 m were preferred over those with shorter vegetation.