Understanding how Temperature influences European Starling’s Reproductive Success

Many habitats face fluctuating temperatures year round. The animals that live there are typically able to adjust their behaviors to match these conditions. When temperatures become too extreme, however, it could potentially start having a negative effect on the animal’s reproductive success. In birds, for example, severe climate can affect their eggs and nestlings due to nestlings lacking the ability to thermoregulate. The parents then have to bear the responsibility of thermoregulation for their young, through a behavior called incubation or brooding. European starlings (Sturnus vulgaris) are a species of birds common across the United States where both parents incubate their eggs and or brood their nestlings. In order to understand how the weather could impact these birds, we used nest cameras to record the behaviors of starling parents from March to June of 2020. We then used NOAA historical weather data to assess whether temperatures during the daytime shaped the number of eggs these starlings laid (clutch size). We also checked to see if weather temperatures effected the incubation and brooding behaviors of parents when they were keeping their nestlings warm (thermoregulation). We hypothesized that extreme temperatures (too warm or too cold) would results in less eggs at the nest, and more parental care from the parents

The Effects of Provisional Rate on Offspring Growth in European Starlings

Offspring rarely have a linear growth rate and many external factors may be to blame for this. They may be most sensitive to their rearing conditions when they grow most rapidly. Parenting and provisional habits are similarly inconsistent and may depend on various factors including the energetic state of the parent or the food availability in the surrounding environment. Though not previously linked before, the connection between parental provisioning efforts and growth and success rate of the offspring may be immense. This study focused on European Starlings (Sturnus vulgaris). The hypothesis tested was that rapid offspring growth may be connected and coincide with an increase in parental provisioning habits. Nest boxes were studied over a course of several weeks, and videos were filmed every other day to allow analysis of provisioning rates. Nestlings were weighed every other day to determine growth rate of the offspring. We will be studying the habits and rates of the parental provisioning as well as other factors such as sex of the bird and weather. These are known factors that affect provisioning habits in birds. We will be presenting results on whether parental provisional care affects the growth rate of the offspring. This will allow scientists to better understand the nonlinear affect that provisioning habits have on the offspring at different stages of development

Multiple achromatic plumage signals of male quality in the snow bunting (Plectrophenax nivalis)

Although males can produce many ornaments, the evolution of multiple ornaments is not well understood. We investigated achromatic plumage traits in the context of multiple ornaments in Arctic-breeding snow buntings ( Plectrophenax nivalis ). We examined whether multiple ornaments: are providing multiple messages, are redundant, are unreliable signals or are aimed at different receivers. We measured plumage reflectance and pigmentation patterns that are differentially, but conspicuously advertised during male inter- and intra-sexual displays. Our results indicate that although several signals are redundant, different body regions appear aimed at different receivers. The wings of males--displayed during courtship--indicate male expected reproductive performance. Conversely, melanin reflectance displayed during intra-sexual threat displays signals territoriality. Different information provided by distinctive aspects of plumage may have differential importance in inter- versus intra-sexual communication. This study demonstrates that even relatively simple plumage traits can serve in complex communication

Costs and Benefits of Breeding Cooperatively in Fluctuating Environments in African Starlings

Global climate change is expected to increase the frequency of extreme and unpredictable weather in many parts of the world. As a result, a critical goal for biologists is to predict how organisms may come to cope with increased environmental variability. The key to making these predictions will be to understand how animals currently living in fluctuating environments are able to survive and reproduce under these conditions. Sociality (i.e. group living) and cooperative breeding (i.e. where more than two individuals care for young together) may both facilitate the colonization of highly fluctuating environments. However, the relative benefits of group living and engaging in alloparental care under variable conditions remain unclear. My dissertation examines the fitness consequences of living in one of the world’s most unpredictable habitats—the African savanna—in a population of free-living cooperatively breeding superb starlings (Lamprotornis superbus). In chapter 1, I examine whether adults benefit from living in large social groups of up to 50 individuals, which are among the largest known for any cooperatively breeding bird. In addition, I test whether group size serves to buffer against harsh environmental conditions. In chapter 2, I examine whether breeders gain reproductive benefits by having alloparents at their nest—I explore the type of reproductive benefits gained (i.e. improved reproductive success versus offspring care load-lightening), as well as whether these benefits occur in both harsh and benign conditions (i.e. temporal variability hypothesis), or are greatest under harsh conditions only (i.e. hard life hypothesis). In chapter 3, I explore whether offspring care load-lightening reduces the cost of reproduction incurred by breeders and alloparents by comparing four physiological mechanisms known to mediate reproductive costs. Lastly, in chapter 4 I test the long-standing assumption that cooperatively breeding species face reduced costs of reproduction by sharing offspring care relative to non-cooperatively breeding species. I compare the oxidative cost of reproduction in superb starlings to greater blue-eared glossy starlings (L. chalybaeus), a synoptic non-cooperatively breeding species. Taken together my dissertation findings demonstrate that group living and alloparental care do not solely buffer against harsh conditions in superb starlings, but instead provide individuals with the flexibility to modify their offspring care behavior according to environmental conditions, to the behavior of other group members, and to their physiological condition prior to breeding—this behavioral flexibility may in turn serve to mitigate fluctuations in the cost of living and breeding in variable environments

Effect of Diet on Window Collision Rate among Bird Species

Every year, over 500 million birds collide fatally with man-made structures, with window collisions playing a significant role in causing these deaths. Our research analyzes how a species’ diet can affect their rates of collision with windows. To explore this question, we analyzed the most common food sources of 87 species of birds from window collision data in metro Atlanta. Our results showed that 77% of species from window collisions (or 67 species) were primarily insectivorous. This reliance on insects as a food source could lead to a lifestyle that tends to bring these bird species in closer proximity to windows more frequently. Consequently, these birds may become more likely to collide with a window while foraging or hunting for food. From an environmental perspective, this research draws close attention to the need to consider diet when analyzing bird-window collisions and preventative measures. In addition, it provides an additional benchmark for assessing collisions, the bird’s diet, that can help target species that are most at risk and would require the most assistance

Effects of sibling competition on growth, oxidative stress, and humoral immunity: a two-year brood-size manipulation

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. . On the basis of annual differences in chicks' morphological traits and body masses close to fledging, we established that 2007 was a relative low-quality year and 2008 was a relatively high-quality year. Total antioxidant capacity (TAC) was significantly lower in experimentally enlarged broods, but only in the low-quality year (2007). Total oxidant status (TOS) was independent of brood size in both years but was 45% higher in the low-quality year. Consequently, plasma oxidative status (the ratio between TOS and TAC) was higher in 2007. In contrast, plasma IgY levels were higher in the experimentally enlarged broods and in the high-quality year (2008). Thus, immune function and oxidative stress showed inverse relationships with developmental conditions and annual variation in year quality. Finally, TOS and TAC were positively correlated, but only in the low-quality year (2007), and there was no relationship observed between IgY and markers of oxidative stress. Our results demonstrate the importance of taking into account year effects or ecological context when assessing environmental effects on physiological mechanisms underlying the life-history traits of chicks, such as oxidative stress. The University of Chicago Pres

Multiple achromatic plumage ornaments signal to multiple receivers

We investigated whether achromatic plumage traits can act as multiple ornaments in an Arctic-breeding passerine, the snow bunting (Plectrophenax nivalis). Specifically, we examine whether multiple ornaments are providing multiple differing messages, are redundant, are unreliable signals of male quality, or are aimed at different receivers. We measured plumage reflectance and pigmentation patterns made conspicuous during male inter-and intrasexual displays that advertise different plumage regions. Our results indicate that although several aspects of male plumage may have redundant messages, different body regions appear aimed at different receivers. The wings of males-displayed primarily toward females during courtship-appear to indicate a pair\u27s future reproductive performance. Conversely, melanin-based plumage reflectance displayed during intrasexual threat displays provides information on territory features and a male\u27s capacity to defend it (i.e., territory size, territory quality, testosterone levels). Taken together, we suggest that snow buntings have multiple ornaments that provide information of differential importance in inter-versus intrasexual communication. This study demonstrates that achromatic plumage traits can serve in complex communication. © 2012 The Author

Sex ratios and the city: Secondary offspring sex ratios, parental corticosterone, and parental body condition in an urban-adapted bird

The Trivers–Willard hypothesis states that mothers should adjust their offspring sex ratio according to their own condition and the environment they face during breeding. Past tests of this hypothesis have focused on how natural variation in weather, food availability, or predation pressure shapes sex allocation trade-offs. However, anthropogenic activities, such as urbanization, can alter all of the above characteristics presenting animals with novel challenges in optimizing their brood sex ratio. Previous research has examined how urban living influences individual body condition in several bird taxa, but few have explored subsequent impacts on secondary offspring sex ratio. One likely mediator of the link between environmental conditions, parental condition, and sex ratios is corticosterone (CORT), the primary glucocorticoid in birds. Research on CORT’s influence on sex ratios has focused solely on maternal CORT. However, for species with biparental care, paternal CORT or the similarity of maternal and paternal phenotypes may also help ensure that offspring demand matches parental care quality. To test these hypotheses, we explore offspring secondary sex ratios in European starlings (Sturnus vulgaris). We did not find an effect of site or parental body condition on the production of the more costly sex (males). Instead, we found preliminary evidence suggesting that the similarity of maternal and paternal CORT levels within a breeding pair may increase the likelihood of successfully fledging sons. Maternal and paternal CORT were not significant predictors of secondary sex ratio, suggesting that parental similarity, rather than parental CORT alone, could play a role in shaping secondary offspring sex ratios, but additional work is needed to support this pattern. Starlings are considered an urban-adapted species, making them a compelling model for future studies of the relationship between urbanization, parental body condition, and sex ratios

Does urbanization affect female and male guarding behavior in European Starlings?

Does urbanization affect female and male guarding behavior in European Starlings? Authors: Nikita Jain 1 Sarah Guindre-Parker 1 1 Kennesaw State University Urbanization drastically impacts biodiversity and can create stress for populations experiencing life in urban centers. In free living European Starlings (Sturnus vulgaris), adults of both sexes provide for and guard the young during their development to independence (called fledging). It’s remains unclear whether urbanization changes guarding behavior of adults due to increased threats in urban areas. We used a multi-site dataset collected on free-living birds of both sexes to identify if there was a larger percentage of time spent guarding the nest in the urban setting than the rural one. More specifically, we wanted to see if the dangers and threats of the urban environment induced a need for greater nest defense by adult starlings. We also examine the difference in the behavior of parents to urbanization by sex—since males usually are more territorial, we hypothesize that males may guard the nest most in urban areas compared to rural males or compared to females. We will discuss how these results may help us design cities that are more bird-friendly

Bird behavior in in the city: is flight initiation distance shorter in more urban trails

Across the country and worldwide, urban areas continue to expand and encroach on previously wild habitats. Urbanization can affect animal behavior as organisms respond to the changes in their environment which they may perceive as stressors. Previous studies have noted that birds in more urban areas tend to have shorter flight initiation distances than those in more rural areas, which is defined as the distance at which a potential threat (here, a human observer) can approach before the animal flees. This study examines whether flight initiation distance changes along the urban to rural gradient in two species of bird (Cardinalis cardinalis and Mimus Polyglottos) in Georgia, USA. A single person walking towards the bird was used to stimulate flight as a disturbance. Birds along urban and rural trails were assayed to test whether perceived threats lead to a shorter flight initiation or shorter distance fled in bold urban birds compared to shy rural ones