Animal Sciences Commons^™

Breeding Densities And Habitat Of Riparian Birds Along The Lower Rio Grande, Texas, Corinna Elizabeth Rupert

Theses and Dissertations - UTB/UTPA

The breeding biology of Snowy Plovers (Charadrius alexanderinus) was studied at Laguna Atascosa National Wildlife Refuge in coastal southern Texas. During 1995 and 1996 nests were found most often in high sand flat habitat and less frequently in low sand flat. Nest sites were dominated by open flat but had more rocks, pebbles and debris than control sites. Only 24% of the clutches hatched, while 67% were eaten by predators and 9% were flooded. Forty-three percent of Snowy Plover nests were within Least Tern (Sterna antillarum) colonies and these nests had a significantly greater chance of hatching than nests placed …

Aquatic Macroinvertebrates Of Rio Grande Delta Ponds, Anna Maria Navarro

Theses and Dissertations - UTB/UTPA

The purpose of this study was to identify aquatic macroinvertebrates living in the vegetated margins of local ponds, to determine their relative abundances, and to construct a rapid bioassessment model. I collected macroinvertebrates seasonally from seven ponds in the Lower Rio Grande Valley. Collection sites included: Moore Airfield, Santa Ana National Wildlife Refuge, and Olmito Fish Hatchery. Twenty-eight samples were sampled and preserved at the University of Texas-Pan American. Seventy-six taxa were identified and were stored as a reference collection. Cluster analysis of the taxa and their relative abundances showed three distinct geographic patterns or regions. These patterns were verified …

Habitat Selection, Population Density, And Home Range Of The Elf Owl, Micrathene Whitneyl, At Santa Ana National Wildlife Refuge, Texas, Christopher Michael Gamel

Theses and Dissertations - UTB/UTPA

The Elf Owl, Micrathene whitneyi, is a regular summer resident of the southwestern United States. My objectives were to collect information concerning habitat selection, home range size, and population density of M. w. idonea, the subspecies occurring in the Lower Rio Grande Valley of Texas. Nocturnal surveys indicated greater use of chaparral habitat (92%) compared to riparian woodlands (8%). Utilized habitat was characterized by highest foliage density at 2.5-3.0 m, with a partial canopy at 3.8 $\pm$ 0.36 m and a semi-open understory. Home range size ranged from 0.24 to 2.6 ha, with a mean of 1.05 $\pm$ 0.33 ha. …

Habitat Use And Activities Of The Piping Plover, Charadrius Melodus, Wintering On South Padre Island, Texas, Humberto Garza Jr.

Theses and Dissertations - UTB/UTPA

The Piping Plover, Charadrius melodus, is endangered in its breeding sites and threatened in its wintering sites. This migratory shorebird spends 3 to 4 months on northern U.S. and southern Canadian breeding sites and the remainder of the year in Gulf of Mexico, Caribbean, and southern U.S. wintering sites. Up to 2.4% of the estimated Piping Plover population remains for the 9 to 10 month non-breeding season on South Padre Island (S.P.I.). During the non-breeding season, I conducted censuses at 15 sites in the southern portion of South Padre Island to determine Piping Plover habitat preferences. Piping Plovers prefer bay …

Red-Breasted Mergansers, Mergus Serrator, Nesting In Southern Texas, Jeffery R. Rupert, Timothy Brush

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

No abstract provided.

Effects Of Competition And Predation On Prothonotary Warblers And House Wrens Nesting In Eastern Iowa, Timothy Brush

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

In a fragmented midwestern floodplain forest, a small Prothonotary Warbler (Protonotaria citrea) population experienced high competition with House Wrens (Troglodytes aedon) and mammalian nest predation in 1988-89. Despite the provision of 3 types of nest boxes and higher water levels, Prothonotary Warblers did not nest successfully and decreased in the fragmented forest in 1990-91. House Wrens used >90% of the nest boxes in both years. Wren territories doubled within the nestbox area, while remaining constant on an unmanipulated area. In contrast, a larger warbler population had high nesting success during 1990-91 in a relatively unfragmented, wetter forest tract. Such forests, …

Seasonal Distribution Of The Ichthyofauna Of Santa Ana National Wildlife Refuge, Alamo, Texas, Matthew Albert Ciomperlik

Theses and Dissertations - UTB/UTPA

This study investigated the small aquatic ecosystems of Santa Ana National Wildlife Refuge, located in a predominantly agricultural area of the Lower Rio Grande Valley, Texas. Fishes and water quality data were collected for 13 months to determine the status of fish populations and the factors which influence their distributions on the refuge.

Sixteen fish species were collected during the study, however, more than 20 species are known to inhabit the Rio Grande in the vicinity of the refuge. Water source played a major role in influencing fish species richness in these aquatic ecosystems. Diverted river water offered the best …

Population Structure, Density And Movements Of The Texas Tortoise Gopherus Berlandieri, Frank W. Judd, Francis L. Rose

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Gopherus berlandieri was studied on a 3.3 ha grid in Cameron Co., Texas for five years. One hundred two tortoises were marked (43 males, 30 females, 26 juv., and 3 adults whose sex was not determined). Numbers of males and females did not differ significantly. Juveniles comprised 27% to 9% of the population and maximum population density was 15 to 16 tortoises per ha. The number of females remained constant, but males and juveniles declined gradually from 1972 to 1975, then markedly in 1976. The percentage of shared individuals in successive years was higher for females than males, but only …

Habitat Selection Related To Resource Availability Among Cavity-Nesting Birds, Timothy Brush

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Variation in snag species and abundance appeared to explain most of the habitat selection patterns observed in five cavity-nesting riparian species over a three-year period. All species except Ash-throated Flycatchers were most common in areas with cottonwood or willow snags, which have relatively soft wood and are preferred nest sites. Classification of habitats on the basis of nest-site characteristics was useful and should be considered in other habitat selection studies.

Flowering Vegetation Of South Texas As An Aggregation Site For Screwworm Flies, Cochliomyia Hominivorax (Coquerel), Geral Lenford Long

Theses and Dissertations - UTB/UTPA

Flowering vegetation was investigated to determine its potential as an aggregation site for the mating of screwworm flies, Cochliomyia hominivorax (Coquerel). Fly activity was observed at vegetation on a typical south Texas shrub community. Noted were the species of vegetation present and the phenology of their flowering. Screwworm flies were found to be attracted to specific species of brush; however, in the absence of the most attractive species, the flies responded to secondary species. Both feeding and mating behavior were observed on vegetation.

Olfaction and visual mechanisms of aggregation were investigated. Results from an olfactometer showed the attractancy of some …