Thesis (Ph. D.)--University of Melbourne, 2004. / Title from PDF title page (viewed on July 22, 2005). Includes bibliographical references (p. 137-160).

A population of Black-capped Chickadees (Parus atricapillus) living in a favourable environment was colour-banded, and its survival was followed, to find out what prevents continual increase in its numbers. A weekly census of the population was made throughout the two years of the study. All nests were found and the young were banded before they flew. Every two weeks throughout both winters checks were also made on an unhanded population in a control area one and a quarter miles from the main population. Nesting success was high in both years, with 5.0 young per pair being fledged in 1964 and 4.5 young per pair in 1965. Juvenile survival until family break-up was almost 100% in both years; juvenile survival until September seemed to be high. The survival rate of the adults was uneven: there were two periods when it was lower than it was during the rest of the year. The less sharply defined period occurred during the post-breeding moult of the adults. The more sharply defined period of two weeks or less was exactly correlated in both years with a change in behaviour from flocking to territorial behaviour. With the exception of one unmated female in each year, every bird which survived this critical period remained to breed or attempt to breed; hence this change in behaviour in the spring evidently removed surplus birds from the area, and thus prevented continual increase in the population. This behaviour may be the common factor that limits the breeding populations of other species with similar ecology. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes bibliographical references (p. 119-141).

Digitized by Kansas Correctional Industries

Invasive species are often implicated in population declines of native species through competition and predation. Red imported fire ant (Solenopsis invicta) predation of songbird nestlings and eggs has been documented. I conducted a replicated manipulative experiment to determine the magnitude of the decrease in nest survival caused by S. invicta in addition to other predators. I conducted mensurative experiments to quantify the frequency of S. invicta foraging near active songbird nests and factors that influence the susceptibility of songbird nests to S. invicta predation. I hypothesized that predation by S. invicta reduced nest survival by 10%, potentially biologically significant, and that songbird nests would be more susceptible to S. invicta predation that were located: (1) closer to the ground, (2) closer to an edge, (3) closer to disturbed soils, and (4) initiated later in the breeding season. I monitored 235 songbird nests including 45 black-capped vireo (Vireo atricapilla), 67 white-eyed vireo (V. griseus), and 123 northern cardinal (Cardinalis cardinalis) nests on 9 patches of 36–103 ha each on private land in east-central Texas, USA in 2006–2007. I found preventing S. invicta from preying upon songbird nests increased nest survival 20% for white eyed vireos and 1% for black-capped vireos. I detected S. invicta near songbird nest on 60% of food lures on the ground and 7% of food lures 1 m high in vegetation (n = 122). Vireo nests <2 m high and <4 m from an edge were more susceptible to S. invicta predation indicating potential threshold conditions, below which songbird nests may be more susceptible. If my results are applicable to other areas then songbird populations of some species nesting below 2 m may have substantially lower nest survival in areas occupied by S. invicta. I suggest the negative impacts of S. invicta on songbird nest survival may be reduced by applying integrated pest management methods and increasing woody vegetation cover in breeding areas of songbird species susceptible to S. invicta nest predation.

Thesis (M.S.)--Villanova University, 2007. / Biology Dept. Includes bibliographical references.

Thesis (M.S.)--Texas State University-San Marcos, 2008. / Vita. Includes bibliographical references (leaves 29-35). Also available on microfilm.

No description available.

Thesis (M.S.)--Villanova University, 2008. / Biology Dept. Includes bibliographical references.

Predation is the leading cause of nest failure in songbirds. My study identified nest predators of black-capped vireos and white-eyed vireos, quantified the activity of potential predator species, examined the relationships between vegetation and nest predators, and examined the relationship between nest predation and parasitism by brown-headed cowbirds. In 2008 and 2009 I monitored black-capped and white-eyed vireo nests on privately-owned properties in Coryell County and black-capped vireo nests on Kerr WMA in Kerr County and at Devils River State Natural Area in Val Verde County (2009 only). I monitored vireo nests using a video camera system to identify predators and nest fate. I also collected at-nest vegetation measurements including nest height, distance to nearest habitat edge, and nest concealment. Additionally, I sampled potential predator activity at a subset of black-capped vireo and white-eyed vireo nests in Coryell County using camera-trap bait stations and herptofaunal traps. I monitored 117 black-capped vireo nests and 54 white-eyed vireo nests. Forty-two percent of black-capped vireo and 35% of white-eyed vireo nests failed due to predation. I recorded >10 total predator species and 37 black-capped vireo and 15 white-eyed vireo nest predation events. Snakes (35%) and cowbirds (29%) were the most frequently identified nest predators; however, major predator species varied by location. I observed no significant relationship between nest fate (fledge vs. fail) and nest concealment or distance to edge for either vireo species. Nest height, concealment and distance to edge may relate to predator species in Coryell Co. for snake species, and Kerr for avian species. Additionally, I observed no difference between the predator activity and the fate of the nest. Both vireos have multiple nest predator species. Additionally, multiple cowbird predations demonstrate this species may have multi-level impacts on vireo productivity, even with active cowbird management. Vegetation structure and concealment may also affect predator species. However, the activity of other predator species near active nests may not negatively affect nest success.