Reproductive success of great blue herons at Nueces Bay, Corpus Christi, Texas
No abstract available.
Bulletin of the Texas Ornithological Society↗
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Evaluation of capture techniques for long-billed curlews wintering in Texas
Texas coast harbors the largest, eastern-most populations of Long-billed Curlews (Numenius americanus) in North America; however, very little is known about their migration and wintering ecology. Curlews are readily captured on their breeding grounds, but experience with capturing the species during the non-breeding season is extremely limited. We assessed the efficacy of 6 capture techniques for Long-billed Curlews in winter: 1) modified noose ropes, 2) remotely controlled bow net, 3) Coda Netgun, 4) Super Talon net gun, 5) Hawkseye whoosh net, and 6) cast net. The Coda Netgun had the highest rate of captures per unit of effort (CPUE = 0.31; 4 curlew captures/13 d of trapping effort), followed by bow net (CPUE = 0.17; 1 capture/6 d of effort), whoosh net (CPUE = 0.14; 1 capturel7 d of effort), and noose ropes (CPUE = 0.07; 1 capturel15 d of effort). No curlews were captured using the Super Talon net gun or a cast net (3 d and 1 d of effort, respectively). Multiple capture techniques should be readily available for maximum flexibility in matching capture methods with neophobic curlews that often unpredictably change referred feeding locations among extremely different habitat types.
Texas↗
Birds of the Rio Grande and other riparian habitats of Western Webb County, Texas
We conducted 164 diurnal morning point counts in 1997 and 89 nocturnal point counts in 1998 along the Rio Grande and at other riparian habitats on remote ranchland in northwestern Webb County. We subsequently conducted 94 diurnal morning and 37 nocturnal point counts in 1999 on public lands along the Rio Grande and at other riparian habitats at Laredo, Webb County. From these systematic surveys (n 384) and other irregular visits to sites during the length of the study, we detected a total of 209 bird species. Many species (97) are distributed widely over much of North America, but substantial numbers of species were also of primarily eastern (30), western (30), southwestern (26), and tropical (26) distributions. Fifty-five of the 209 species (26%) occur on >1 species priority lists in six bird conservation plans that we reviewed, but only four of these were tropical species. This suggests that tropical species, the driving force behind ecotourism-sustained economies in southern Texas, may not benefit directly from recent bird conservation plans, since their lists of priority species do not include many tropical birds. Thus, conservation projects designed to benefit primarily tropical species will not be ranked highly for funding if evaluated on the basis of the bird conservation plans we reviewed.
Bulletin of the Texas Ornithological Society↗
Colonial nesting Yellow-crowned Night Herons on the San Antonio River Walk
Yellow-crowned Night Herons (Nyctinassa violacea) typically nest as single pairs or in small colonies of about four pairs with high internest distances. They are also reported as susceptible to disturbance and to avoid habitat with high human use. However, some Yellowcrowned Night Herons habituate to human-dominated landscapes and nest in residential areas. I located a colony of nesting Yellow-crowned Night Herons in San Antonio, Texas on the River Walk, a popular tourist destination with an estimated 2.5 million visitors annually. I located 68 and 71 active nests in 2008 and 2009, respectively. This suggests the breeding population of the colony was 142 adult birds (77 adult herons/linear km of River Walk) in 2009. Herons occurred in a colony with three nesting aggregations situated 241 (±14 SD) m apart. Aggregations averaged 23.7 (±8.7 SD) nests each with one–nine nests per tree; nest trees within each aggregation were usually adjacent. Nests averaged 16.7 m (±4.1 SD) above ground, with 56% of nests over the river, 23% over sidewalks, 17% over dining areas, and 3% over landscaping. Only bald cypress (Taxodium distichum) was used for nest trees, and these were significantly taller and larger in diameter than random bald cypress trees. The herons were habituated to pedestrian activities, often perching only a few meters over sidewalks or dining areas, and foraging along the water’s edge as pedestrians passed within 4–5 m. Nests located over dining areas and sidewalks do impose some management issues. It is apparent the species is capable of habituating to human activities to exploit suitable urban settings for nesting and foraging habitat.
Texas↗
Assessment of lesser prairie-chicken use of wildlife water guzzlers
Man-made water sources have been used as a management tool for wildlife, especially in arid regions, but the value of these water sources for wildlife populations is not well understood. In particular, the value of water as a conservation tool for Lesser Prairie-Chickens ( Tympanuchus pallidicinctus ) is unknown. However, this is a relevant issue due to a heightened conservation concern for the species and its occupancy of an arid landscape anticipated to experience warmer, drier springs and winters. We assessed if Lesser Prairie-Chickens would use commercially available wildlife water guzzlers and if there was any apparent selection between two design types. We confirmed that Lesser Prairie-Chickens would use bird friendly designed wildlife water guzzlers. Use was primarily during the lekking-nesting period (March–May) and the brood rearing period (June–July) and primarily by males. Although both designs were used, we found significantly greater use of a design that had a wider water trough and ramp built into the tank cover compared to a design that had a longer, narrower trough extending from the tank. Although we were unable to assess the physiological need of surface water by Lesser Prairie-Chickens, we were able to verify that they will use wildlife water guzzlers to access surface water. If it is found surface water is beneficial for Lesser Prairie-Chickens, game bird friendly designed guzzlers may be a useful conservation tool for the species.
Bulletin of the Texas Ornithological Society↗
Golden Eagle predation of an adult turkey vulture
The Golden Eagle (Aquila chrysaetos) is a large, apex predator that occurs at low densities, has a long life span, experiences delayed maturity, has low reproductive rates, and has no natural predators (Watson 1997, Kochert et al. 2002). Golden Eagles are sensitive to anthropogenic driven landscape changes in land cover and land use (Hunt 2002, Kochert and Steenhof 2002). Landscape level alterations, such as encroachment of woody vegetation in eagle foraging areas, may result in decreased abundance of suitable prey or interfere with the eagle’s ability to see or capture prey. Currently, there is substantial concern for Golden Eagle conservation due to widespread anthropogenic changes to landscapes across much of the species distribution (U.S. Fish and Wildlife Service 2013). In particular, the rapid expansion of wind energy development has led to heightened concerns for Golden Eagle conservation, as the species is susceptible to mortality through collision with turbines (Hunt 2002, U.S. Fish and Wildlife Service 2013). This has resulted in a recent increase in research to develop a better understanding of the species’ ecology.
Bulletin of the Texas Ornithological Society↗
Urban nesting by a broad-winged hawk pair in the southern High Plains of Texas
No abstract available.
Texas↗
Assessing cormorant populations and association with fish stocking in Texas
—Double-Crested Cormorants ( Nannopterum auritum ) and Neotropic Cormorants ( Nannopterum brasilianum ) are thought to be expanding their populations across Texas. This expansion is cause for a concern for both fish stocking and fisheries management in public waters. To examine the historic and current populations and distributions of cormorants, we first evaluated the temporal and spatial patterns of cormorants in Texas. Also, because cormorants are thought to depredate public fisheries, we conducted a small observational field study to assess cormorant presence and behavior at lakes relative to fish stocking. We compiled Christmas Bird Count (CBC) data for both species over a period of fifty years (1970 to 2019). We assessed changes in detection rates at CBCs among years as evidence of population trends during the winter, and changes in distance from the Gulf Coast of CBCs reporting cormorants for evidence of changes in distribution. Our results suggest that winter populations of Double-Crested Cormorants are relatively stable, with no meaningful change in distribution. In contrast, Neotropic Cormorants appear to be both increasing in number and expanding their range. Our assessment of cormorant abundance and behavior at stocked and unstocked lakes from December through February revealed a significant difference in detections among the stocked lakes during pre- and post-stocking but no significant difference among the control lakes.
Texas↗