Male ring doves ( Streptopelia risoria ) held on long days perform more nest-building than birds held on short days. This difference persists even if circulating androgen is maintained at similar levels in both groups by castration and treatment with exogenous testosterone. It therefore appears that daylength can alter nest-building through some means other than changes in gonadal androgen production. The experiments described in this thesis examined three mechanisms which might be responsible for the effect of daylength on male nest-building. The first series of experiments tested the hypothesis that nest-building activity is greater under long days as a result of increased aromatization of testosterone into estrogen. Castrated male doves were implanted with estradiol benzoate, testosterone propionate (TP), or a combination of TP and an aromatase inhibitor, ATD, and exposed to either long or short photoperiods. Males held under long days continued to build more actively, regardless of the type of hormone being used. The results thus indicate that differences in the rate of aromatization cannot account for the effect of photoperiod. In a second series of experiments an attempt was made to determine whether an increase in the production of hypothalamic luteinizing hormone releasing hormone (LHRH) under long daylengths stimulates nest-building, as a result of a synergism with testosterone. Long- and short-day castrated males were treated with exogenous TP or TP and LHRH to see if the influence of short daylengths could be reversed by LHRH. LHRH treatment had no effect on the nesting activity of either short- or long-day birds. Finally, several tests were performed which focussed on the role of the pineal gland. Removal of the pineal caused a decrease in nesting activity in long-day birds, but not in short-day birds. The effect of pinealectomy does not depend on the presence of the gonads, since the birds displayed similar responses following castration and testosterone treatment. In the second test, the ability, of pinealectomy to nullify the stimulatory influence of long daylengths was confirmed. In addition, injections of chicken pineal extract increased nest-building in pinealectomized and in short-day pineal-intact birds, suggesting that the pineal produces a substance which is capable of stimulating nesting activity. The identity of this substance is unknown. Pilot tests using melatonin failed to show any stimulatory effect of this compound on nesting behaviour. However, serotonin, which is also present in the pineal in high concentration, did increase nest-building in short-day pinealectomized males. These results indicate that in response to long daylengths the pineal gland of male doves releases a compound, possibly serotonin, which stimulates nest-building activity. / Science, Faculty of / Zoology, Department of / Graduate

Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol) / It is widely reported that snakes can be major predators of avian nests, but the use of a single avian prey type by competing species has rarely been examined. This study aimed to investigate predation of a single food resource by the sympatric snakes Naja nivea and Dispholidus typus. Specifically, I aimed to 1) identify factors influencing snake presence in sociable weaver colonies and 2) quantify snake predation and potential differences in the consumption of prey by the two competing snakes. I used repeated visual surveys of sociable weavers to obtain presence-absence data of cape cobra and boomslang in sociable weaver colonies over an entire breeding season. I related the presence-absence data of the two snake species to spatially- and temporally-variable factors using principal component analyses (PCA) and multiple logistic regression analyses. The presence of snakes in sociable weaver colonies is primarily influenced by temporal factors, but spatial factors also play a role.

Theoretical part of this diploma thesis describe Kaizen method and parts of this method, which was developed in Japan after the Second World War. One part of this method is the 3MU concept, that includes definition of absences which influence all companies. One concept of the 3MU is “Muda”, who indicate waste. Practical part is interesting in wastes in sphere of productivity at one of the production department of the Bosch Diesel Ltd. in Jihlava. Individual operations of this department are considered in light of possibility introduction of more-machine operation and the checking of necessity of some machines. As a result is time data evaluation by REFA method and check of possibility introduction of more-machine operation with modification of working processes, calculation of industrial production capacity of some machines and the definition of buffer stocks. This modification of working processes, number of machines and the definition of buffer stocks needs change of layout of production department. At the conclusion there are calculated final costs and savings for implementation of this project.

Populations of birds of prey, henceforth raptors, have declined worldwide, mostly from anthropogenic causes. Because their role as apex predators in ecosystems is considered vital for ecosystem health, conservation efforts have been implemented throughout their distribution. In many cases, we do not know enough about their basic food and habitat requirements, which is requisite if we are going to be able to protect them. The purpose of this study was to describe the habits and biology of nesting martial eagles by looking at the chick’s diets and the roles of male and female eagles in provision and presentation (dismemberment) of prey to the chicks. Data were collected non-obtrusively by fitting five nests in the Maasai Mara and one in the Rift Valley region of Kenya with cameras that were both motion-triggered and programmed to take images every five minutes. Based on analysis of 214,000 image frames, the diet of nesting martial eagles and their chicks was found to be comprised of 23 different species within four broad prey categories (gamebirds, domestic poultry, large ungulates and small ungulates), of which gamebirds were the most important. There were sex-based differences in parental feeding, with females selecting for larger and heavier prey items than males. Males were the primary foragers for the chicks up until the eighth to eleventh week of chick development, after which the females became more involved. In addition, before delivery to the nest, large prey were more often dismembered than small and medium-sized prey. This study is the first in Africa to use nest-cams to study martial eagles over the breeding season, corroborating previous studies that have shown sex-dependent differences in chick nurturing. My results contribute to establishing a fuller picture that can be used in future conservation actions and management decisions that can be used to protect this species and their prey base. / Beståndet på rovfåglar (hädanefter raptor) har minskat över hela världen, mestadels på grund av all antropomorfisk verksamhet. Eftersom deras roll som topprovdjur i ekosystem anses vara oerhört viktig för ekosystemens hälsa har bevarandeinsatser genomförts i alla deras habitat. I många fall vet vi inte tillräckligt om deras grundläggande mat- och livsmiljökrav, vilket är nödvändigt om vi skall kunna skydda dem. Syftet med denna studie var att beskriva habitat och biologi hos häckande stridsörnar genom att titta på ungarnas dieter och rollen som hanor och honor i tillhandahållande och presentation (rivning) av byte till ungarna. Data samlades in genom att använda en icke-störande teknik. Kameror som var både rörelsestyrda och programmerade att ta bilder var femte minut monterades vid fem bon i Maasai Mara och en i Rift Valley-regionen i Kenya. Baserat på analys av 214 000 bildramar konstaterades att dieten för häckande stridsörnar och deras ungar bestod av 23 olika arter inom fyra breda byteskategorier (viltfåglar, tamfåglar, stora hovdjur och små hovdjur), varav viltfåglar var de viktigaste. Det fanns könsbaserade skillnader i kost som ungarna fick, med honor som valde större och tyngre byte än hanar valde. Hanar var de främsta furagerare fram till den åttonde veckan av ungarnas utveckling, då blir honor mer involverade. Dessutom blev stort byte ofta delade ned innan leverans till boet än små och medelstora byten. Denna studie är den första i Afrika som använde kamror för stridsörnar under Häckningssäsong och den bekräftar tidigare studier som har visat könsberoende skillnader i skötsel av ungar. Mina resultat bidrar till att skapa en mer fullständig bild som kan användas i framtida bevarandeåtgärder och förvaltningsbeslut som kan användas för att skydda denna art. / <p>Due to Covid-19 all presentations and defences were held online</p>

Dual-earner couples raising children face stress that can interfere with marital happiness. Some of these couples seek help from marriage and family therapists, but many therapists claim they are not well trained in the issues facing these couples. In order to determine what might help therapists. researchers in the past have traveled two scholarly paths: (a) studying dual-income couples who still have children at home and are dealing with the stressors of this lifestyle with varying degrees of success, and (b) asking long-term, happily married couples what helped them stay together successfully. This study combined both approaches. Dual-earner couples whose chi ldren were grown and who identified themselves as having great marriages refl ected on strategies that helped them develop and maintain successful and satisfying marriages. Implications for marital therapy are discussed.

Woodpeckers create nesting cavities for other birds and animals in forests. This creates dynamic interactions between both woodpeckers and these other animals. Using video cameras, we documented direct behavioral interactions between nesting woodpeckers and other animals in the Eastern Washington Cascades during the 2015 and 2016 breeding seasons. Additionally, we offered 937 students in a General Biology laboratory course to participate in this original research opportunity and described and the impact the experience had on the participants as well as the researchers. In 2015, Western Blubebirds took over two active Black-backed Woodpecker nests by physically attacking the woodpeckers. In 2016, almost half of the woodpecker nests were reused by other animals, with Western Bluebirds being are most common SCU. We found that some nests we reused within minutes to hours of vacancy. However, we were not able to significantly predict nest reuse or the presence of other animals at the nest. Parent woodpeckers towards avian cavity nesters when compared to rodent, predators, and other woodpeckers. Our fine-scale analysis provides a new window into behavioral interactions at woodpecker nests and same-season nest reuse, but it is limited by its scope. Thus, we suggest for larger-scale video studies examining behavioral interactions around the nest. About 15% of students in the course participated in our research, and we found that students accurately recorded data approximately 90% of the time. Most students came away from the experience with a more positive attitude towards undergraduate research and were able to restate the main research question. However, many students had difficulty understanding their role as a data collector. We suggest making the experience mandatory to include all students and placing a greater emphasis on the process of science.

No description available.

Life history of Phoxinus tennesseensis (Tennessee dace), a species deemed "in need of management" in Tennessee and endangered in Virginia, was investigated from August 1999 to May 2001 on 2 populations in Trinkle Creek and Timbertree Branch, Sullivan County, Tennessee. Samples were taken monthly to provide information on growth, reproductive biology, preferred habitat, and demography. Observations were made during the breeding season to determine spawning strategy. Breeding season lasted from April to June. Spawning occurred over the nest of Semotilus atromaculatus (creek chub) and Campostoma anomalum (central stoneroller). With 1 to 10 females, 20 to 45 male dace gathered over the nest. Phoxinus tennesseensis populations have 4 age classes. The normal life span of the dace was about 2 years with 1st year fish constituting a majority of the total population. Historic populations and potentially new populations were sampled to determine the current distribution in Northeast Tennessee.

The Northern Goshawk has been a species of concern since its decline in the early 1990s, which has been attributed in part to loss of critical breeding and wintering habitat. Nest site selection of goshawks has been correlated with certain specific site characteristics including, but not limited to, forest species composition, forest stand size, diameter of nest tree, percent cover, tree height, site slope, and aspect. The goshawk holds the status of a Management Indicator Species (MIS) on all of the six national forests in Utah. This status requires annual monitoring to track goshawk numbers and to address any activities on the forests that may affect nest site activity. Findings from the annual nesting data showed that some territories have been more active than others. We summarized the data from the three national forests in southern Utah in order to understand differences in nesting habitat among the forests. We also analyzed the nesting habitat variables slope, elevation, and nest tree species statistically to determine if they could be used as predictors of nest activity. We found that slope and elevation were not good predictors while nest tree species was significant in its ability to predict nest activity. We concluded the nesting habitat variables we selected were insufficient in their ability to predict nest activity and other variables such as prey species availability, weather conditions in the spring, and forest cover type might be needed to create a model that more accurately predicts nest activity.

Individual organisms often use cues from their natural environments to determine many behavioral and life-history "decisions." These "decisions" are usually adaptive, i.e. a response to selection, because the environmental cues on which they are based reliably correlate with increased fitness over time. When the selected behavioral response to a natural cue no longer provides a fitness benefit, then selection for a new response may occur but individuals maintaining the previously selected response may suffer reduced survival and reproduction. Especially in human-modified landscapes individuals making a maladaptive behavioral or life-history choice based on those formerly reliable environmental cues may be faced with an "evolutionary trap". In urban, or suburban, environments many factors have been altered in ways that could lead to evolutionary traps. Inappropriate behavioral responses by many individuals could lead to reduced demographic performance of urban populations relative to their wildland counterparts and to the decline of entire urban populations. In birds, maladaptive patterns of nest provisioning or vigilance may occur (a) when human-provided adult foods are easier to feed young because they are more abundant and predictable than foods appropriate for nestlings, or (b) when birds' perception of predation risk, which can be influenced by human disturbance, is greater than the real risk. By provisioning or attending their nests more or less than what is appropriate given the environmental level of resources and risks, the behavior of suburban parents may be contributing to high levels of nest failure during the nesting stage. To determine whether maladaptive parental care influences nest survival during the nestling stage, I conducted an experiment using Florida Scrub-Jays (Aphelocoma coerluscens). Suburban scrub-jays have lower nest survival during the nestling stage but higher survival during the incubation stage relative to wildland jays. Both predators and food abundance vary greatly between suburban and wildland scrub. The suburbs have a greater abundance of predators that may prey on both adult scrub-jays and their nests and more foods appropriate for adults but less nestling-appropriate food. This variation in risks and resources should affect the parental care behavior of suburban scrub-jays, which in turn may affect patterns of nest survival. In pre-treatment observations, I found that suburban females spent more time brooding than wildland birds but suburban males did not provision any more than wildland males. Experimentally increasing the perception of adult predation risk reduced parental care in both suburban and wildland females. Increasing the availability of nestling food reduced parental care in suburban females but had no effect in wildland females. Increasing food availability, but not predation risk, decreased call rates but increased call frequency in nestling scrub-jays from both habitats. However, neither parental care nor food availability had much influence on nest survival during the nestling stage. Instead, side nest concealment and the presence of helpers were the most important variables in nest survival analyses prompting other explanations besides maladaptive parental behavior or lack of nestling food resources for the habitat-specific difference in nest survival during the nestling stage.