<p> The Pacific Coast population of the western snowy plover (<i>Charadrius nivosus</i> nivosus; plover) is listed as a federally threatened species under the U.S. Endangered Species Act due to poor reproductive success from anthropogenic habitat loss, and high predation pressure. Plovers in the South San Francisco Bay use dry salt evaporation ponds, and wildlife-managed ponds, to breed and winter. However, the South Bay Salt Pond Restoration Project aims to restore up to 6,110 hectares of this habitat back to native tidal marsh, which will force plovers to breed in smaller areas and in higher densities. In order to recover plovers in these unique conditions, remaining habitat can be enhanced using oyster shells, which may camouflage breeding plovers, and decrease predation. This study evaluated the effect of oyster shell enhancement on plover breeding success by comparing nesting density, success, and brood behavior between enhanced and unenhanced areas. Plovers did select to nest in enhanced areas; however, nest survival did not increase relative to unenhanced areas. Brood behavior was also affected by enhancement, though highly correlated with the location of optimal foraging habitat. It is likely that enhancement will only improve nesting success if predators are concurrently controlled. Ultimately, plovers may benefit from the application of oyster shells as it attracts nesting effort, and may be strategically used by resource managers.</p><p>

Virtually any person exposed to American movies or television has likely heard the call of a common loon (Gavia immer). Its use as a sound prop has become ubiquitous in any scene related to the outdoors or the wilderness, even if the area filmed is in no way related to true loon habitat. The reason behind this is that the common loon and its haunting cries have come to symbolize the great outdoors. The sound of their call is meant to make the audience feel like the scene they are watching is in a remote area, far from the trappings of civilization, and, in our experience, it works. Hollywood has picked up on a sentiment held by many outdoor enthusiasts and is using it successfully. Unfortunately the southern range of the common loon is contracting and concern has been expressed over disturbance to breeding pairs by human activities, such as shoreline development, boating, and water-skiing, as well as possible contamination with lead, mercury, and other pollutants. If this alarming trend continues it may be that Hollywood movies will be the last place where a loon call can be heard in the United States. In the following chapters I will explore various threats to common loon populations. I will start in Chapter 1 with an evaluation of the potential effects of global warming on common loons within the North American breeding range. In Chapter 2 I review the available literature on wildlife disturbance and discuss some of the shortcomings and future research needs. I then go to a finer scale of study in Chapter 3 with a spatial analysis of disturbance factors and the effects on breeding common loons at Lake Umbagog National Wildlife Refuge. From there, in Chapter 4, I proceed to an analysis of specific behavioral responses exhibited by common loons in response to observed and experimentally imposed disturbance events. Finally, in Chapters 5 and 6, I briefly describe two natural disturbance events observed during our research, an immature bald eagle (Haliaeetus leucocephalus) predating a loon nest, and a loon nest defense of an aggressive American mink ( Nevison vison).

The world’s biodiversity is concentrated in tropical ecosystems, yet tropical forests are being converted for agriculture at a rapid rate. I evaluated the potential of an alternative coffee production system known as Integrated Open Canopy (IOC) to contribute to avian conservation. This study was conducted from 2005–2010 in the Cordillera de Tilarán, Costa Rica. My results indicate that species richness of forest-dependent birds was significantly higher in IOC farms than in shade coffee farms, and was comparable to secondary forest sites. There was no difference in species richness of Neotropical-Nearctic migrants between IOC and shade coffee farms. Overall similarity was higher between IOC farms and primary forest than between shade coffee farms and primary forest. The golden-winged warbler (Vermivora chrysoptera) is a declining Neotropical-Nearctic migrant bird, yet little is known about its non-breeding season ecology and demographics. I found that golden-winged warbler abundance was highest at intermediate precipitation levels found at middle elevations (1000–1200 m) of the Pacific slope, but they were absent from the dry forests at lower elevations on the Pacific slope. Abundance peaked in forests with canopy heights of 22 m, and was positively related to the quantity of hanging dead leaves. Radio-telemetry data indicated that golden-winged warblers used microhabitat features characteristic of disturbance more frequently than expected by chance. Selection of these microhabitat features was related to their highly specialized dead-leaf foraging behavior, which may also have contributed to their high degrees of site fidelity, mixed-species flock attendance, and territoriality. These behaviors have important conservation implications because they constrain density, and thus could affect carrying capacity. Population dynamics were characterized by estimating plot-level and individual-level apparent survival and recruitment rates within and among non-breeding seasons. Both levels of analysis suggested that recruitment was too low to offset mortalities within this study area. This study indicates that increasing forest cover in tropical agricultural landscapes may be the most effective way of providing habitat for bird species of high conservation concern, including the golden-winged warbler. Integrated open canopy coffee production is one option for achieving this goal because it provides a financial incentive to protect or restore forest.

No description available.

Thesis (Ph. D.)--University of Chicago, Department of Anthropology, December 1999. / Includes bibliographical references. Also available on the Internet.

Thesis (M.Anim.Sc) - University of Queensland, 2005. / Includes bibliography.

No description available.

No description available.

I measured characteristics of vegetation around middens of the endangered Mount Graham red squirrel (Tamiasciurus hudsonicus grahamensis) in the Pinaleno Mountains of southeastern Arizona. Midden sites were compared to random sites in both the spruce/fir and transition-zone forests. Foliage volume, canopy closure over plot center, volume of downed logs &ge;20 cm in diameter, and density of snags >40 cm in diameter at breast height (dbh) were greater at midden sites and best distinguished midden sites from random sites in both forest types. The mean stand age of midden sites was >230 years in the spruce/fir forest and >200 years in the transition-zone forest. As regeneration of disturbed sites will take long periods of time, management applications to protect the red squirrel must focus on preserving existing habitat by limiting activities that remove large trees, snags, or logs, open the forest canopy, create forest edge, or otherwise disrupt forest integrity.

I quantified several aspects of hibernacula use and estimated home ranges of desert tortoises (Gopherus agassizii) in the San Pedro Valley, Arizona. Tortoises hibernated primarily on steep southerly slopes. Hibernacula included burrows in silt, silt with loose gravel, diatomite and/or diatomaceous marl, and beneath an ash layer, often in conjunction with live vegetation, dead and downed vegetation, and packrat (Neotoma albigula) nests. Male tortoises used longer hibernacula than females (p < 0.02). Female maximum hibernacula temperatures were consistently higher than male maximum hibernacula temperatures, but the difference was not significant (0.05 < p < 0.10). Female minimum hibernacula temperatures were significantly lower than males (p < 0.001) and female hibernacula temperatures fluctuated over a significantly wider temperature range than males (p < 0.01). Hibernacula used by males provided greater thermal buffering than those used by females. Duration of hibernation was positively correlated with shelter length. Home-range estimates did not differ significantly between males and females.