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Articles 61 - 90 of 264

Full-Text Articles in Ornithology

Non-Lethal Predictors Of Organ Level Metal Contaminants In Central Florida Red-Shouldered Hawks, Jennifer Bouchenot Jan 2021

Non-Lethal Predictors Of Organ Level Metal Contaminants In Central Florida Red-Shouldered Hawks, Jennifer Bouchenot

Electronic Theses and Dissertations, 2020-2023

Elemental contaminants aggregate in the environment due to human activity and can induce detrimental physiological effects within organisms. Birds exhibit exceptional susceptibility to many pollutants and are popular biomonitoring agents throughout the world. Birds of prey are of special interest due to their substantial biomagnification potential. Lethal sampling of internal organs yields accurate contaminant measurements, but recent sampling trends are endeavoring towards non-destructive sampling such as feathers. This methodological shift stems from researchers' preference for less-regulated samples, enhanced animal welfare, and broadening the possible collaborative audience with simpler protocols. Unfortunately, investigations of feathers have shown that their accuracy is capricious …


A Decision Tool To Identify Population Management Strategies For Common Ravens And Other Avian Predators, Andrea F. Currylow, Brenda J. Hanley, Kerry L. Holcomb, Timothy Shields, Stephen Boland, William I. Boarman, Mercy Vaughn Jan 2021

A Decision Tool To Identify Population Management Strategies For Common Ravens And Other Avian Predators, Andrea F. Currylow, Brenda J. Hanley, Kerry L. Holcomb, Timothy Shields, Stephen Boland, William I. Boarman, Mercy Vaughn

Human–Wildlife Interactions

Some avian species have developed the capacity to leverage resource subsidies associated with human manipulated landscapes to increase population densities in habitats with naturally low carrying capacities. Elevated corvid densities and new territory establishment have led to an unsustainable increase in depredation pressure on sympatric native wildlife prey populations as well as in crop damage. Yet, subsidized predator removal programs aimed at reducing densities are likely most effective longer-term when conducted in tandem with subsidy control, habitat management, and robust assessment monitoring programs. We developed decision support software that leverages stage structured Lefkovitch population matrices to compare and identify treatment …


Searching For Gold: Using A Novel Land Cover Classification To Identify Multiscale Drivers Of Site Occupancy By A Flagship Species For Early-Successional Habitat Conservation, Baron Lin Jan 2021

Searching For Gold: Using A Novel Land Cover Classification To Identify Multiscale Drivers Of Site Occupancy By A Flagship Species For Early-Successional Habitat Conservation, Baron Lin

Theses and Dissertations

Understanding habitat selection at multiple scales is an important step in guiding conservation programs and reversing species declines. This, however, is difficult for species that occupy early-successional habitats (ESH) due to a lack of accurate representation of shrub cover in publicly available land cover data. The Golden-winged Warbler (Vermivora chrysoptera; GWWA) is a threatened species of conservation concern and a flagship for ESH conservation. We used a novel, LIDAR-derived land cover classification that accurately identifies shrubs at a fine resolution (1m) to investigate how habitat composition and configuration influence GWWA site occupancy. We aggregated this same land cover …


Inter- And Intra-Annual Effects Of Lethal Removal On Common Raven Abundance In Nevada And California, Usa, Shawn T. O'Neil, Peter S. Coates, Julia C. Brockman, Pat J. Jackson, Jack O. Spencer Jr., Perry J. Williams Jan 2021

Inter- And Intra-Annual Effects Of Lethal Removal On Common Raven Abundance In Nevada And California, Usa, Shawn T. O'Neil, Peter S. Coates, Julia C. Brockman, Pat J. Jackson, Jack O. Spencer Jr., Perry J. Williams

Human–Wildlife Interactions

Populations of common ravens (Corvus corax; ravens) have increased rapidly within sagebrush (Artemisia spp.) ecosystems between 1960 and 2020. Although ravens are native to North America, their population densities have expanded to levels that negatively influence the population dynamics of other wildlife species of conservation concern, such as greater sage-grouse (Centrocercus urophasianus) and desert tortoises (Gopherus agassizii). For this reason, lethal removal, such as the application of the avicide DRC-1339, has been used to manage raven numbers at local scales and under certain circumstances. Because the relative effectiveness of DRC-1339 in reducing raven …


Demography, Morphometrics, And Stomach Contents Of Common Ravens Examined As A Result Of Controlled Take, Corinne M. Gibble, Kriss K. Neuman, Jessie Beck Jan 2021

Demography, Morphometrics, And Stomach Contents Of Common Ravens Examined As A Result Of Controlled Take, Corinne M. Gibble, Kriss K. Neuman, Jessie Beck

Human–Wildlife Interactions

Common ravens (Corvus corax; ravens) are known nest predators that have the ability to negatively impact nesting birds, including imperiled species of seabirds and shorebirds. We conducted systematic necropsies of ravens that were lethally controlled in Monterey Bay, California, USA during 2013–2015, in or near western snowy plover (Charadrius nivosus nivosus) nesting areas, in an effort to better understand body condition, overall health, and diet of individual ravens. Raven predation of snowy plover nests has increased over the years in the Monterey Bay study area, and lethal removal of ravens has been employed to reduce predation. …


Predation Threat In A Variable Landscape: Connecting Predation Risk To Nesting Success For The Seaside Sparrow (Ammospiza Maritima Macgilivraii), Corina D. Newsome Jan 2021

Predation Threat In A Variable Landscape: Connecting Predation Risk To Nesting Success For The Seaside Sparrow (Ammospiza Maritima Macgilivraii), Corina D. Newsome

College of Graduate Studies: Theses & Dissertations

Predation, the leading cause of nest-failure in birds, not only exists as a direct threat to nesting success, but may exacerbate other sources of nest mortality. Birds inhabiting Atlantic coastal marshes, such as Seaside Sparrows (Ammospiza maritima; hereafter SESP), are experiencing significant and rapid changes to their habitat, particularly sea level rise (SLR) and encroaching urbanization, that may affect the relative influence of nest predation on overall productivity. For SESPs, SLR presents an inherent threat to nest success in its potential to increase the frequency of nest flooding. In addition to this direct threat, the ability of SESPs …


Long‐Distance Natal Dispersal Is Relatively Frequent And Correlated With Environmental Factors In A Widespread Raptor, Hanna M. Mccaslin, T. Trevor Caughlin, Julie A. Heath Sep 2020

Long‐Distance Natal Dispersal Is Relatively Frequent And Correlated With Environmental Factors In A Widespread Raptor, Hanna M. Mccaslin, T. Trevor Caughlin, Julie A. Heath

Biology Faculty Publications and Presentations

  1. Dispersal is a critical process influencing population dynamics and responses to global change. Long‐distance dispersal (LDD) can be especially important for gene flow and adaptability, although little is known about the factors influencing LDD because studying large‐scale movements is challenging and LDD tends to be observed less frequently than shorter‐distance dispersal (SDD).
  2. We sought to understand patterns of natal dispersal at a large scale, specifically aiming to understand the relative frequency of LDD compared to SDD and correlates of dispersal distances.
  3. We used bird banding and encounter data for American kestrels (Falco sparverius) to investigate the effects of …


Sensory Stressors Impact Species Responses Across Local And Continental Scales, Ashley A. Wilson Sep 2020

Sensory Stressors Impact Species Responses Across Local And Continental Scales, Ashley A. Wilson

Master's Theses

Pervasive growth in industrialization and advances in technology now exposes much of the world to anthropogenic night light and noise (ANLN), which pose a global environmental challenge in terrestrial environments. An estimated one-tenth of the planet’s land area experiences artificial light at night — and that rises to 23% if skyglow is included. Moreover, anthropogenic noise is associated with urban development and transportation networks, as the ecological impact of roads alone is estimated to affect one-fifth of the total land cover of the United States and is increasing in space and intensity. Existing research involving impacts of light or noise …


A Test Of The Sexually Selected Egg Color Hypothesis In Eastern Bluebirds (Sialia Sialis), Annabelle Mckie-Voerste Aug 2020

A Test Of The Sexually Selected Egg Color Hypothesis In Eastern Bluebirds (Sialia Sialis), Annabelle Mckie-Voerste

Student Theses and Dissertations

The broad array of colors represented in avian eggshells has promoted extensive investigations into its evolutionary significance. Although many hypotheses exist that explain conspicuous egg colors, including egg recognition against brood parasitism, protection from UV rays, and thermoregulation, they fail to adequately explain the adaptive function of vivid blue eggs. The Sexually Selected Egg Color Hypothesis (SSECH) states that blue-green eggshell coloration is a post-mating, sexually selected signal that conveys female quality, and male birds that observe more pigmented eggs would increase their care accordingly, resulting in higher quality chicks. Using a population of eastern bluebirds (Sialia sialis) in northeast …


Exploring The Effects Of Geographic And Landscape Variation On Avian Communities And Species, Joseph Youtz Aug 2020

Exploring The Effects Of Geographic And Landscape Variation On Avian Communities And Species, Joseph Youtz

Student Theses and Dissertations

Ongoing and intensive anthropogenic change has modified the globe across multiple scales, yet the influence of these modifications on wildlife communities and individuals remain region and species specific. Here I explored the influence of a biogeographical pattern as it relates to climate and geography, and the effects of historic habitat loss and fragmentation on a diverse avian community. I first explored the adherence to Bergmann’s rule within a migratory songbird, the Prothonotary Warbler (Protonotaria citrea), across all life stages and time. The pattern was present from the young nestling stage through adulthood, although contemporary eggs followed a reverse relationship with …


Cerulean Warbler Habitat Selection, Breeding Biology, Survival, And Space Use In The Ozark Region, Jacob Louis Wessels Aug 2020

Cerulean Warbler Habitat Selection, Breeding Biology, Survival, And Space Use In The Ozark Region, Jacob Louis Wessels

Student Theses and Dissertations

For many declining migratory birds, gaps in information on their ecology can impede conservation efforts. Cerulean Warblers (Setophaga cerulea; hereinafter ceruleans) are one such rapidly declining species and have regional ecological variation, so more comprehensive information may benefit their effective conservation. We studied ceruleans in the Ozark region of Arkansas to increase the scientific knowledge of this species in an understudied region that likely supports a ‘natural population’ of ceruleans. We assessed habitat selection, breeding biology, survival, and space use of ceruleans. Consistent with other regions, ceruleans at our study sites selected areas with large trees across spatial scales. Males …


Glare Reduction By Dark Facial Markings And Bills In Birds, Clara Lebow May 2020

Glare Reduction By Dark Facial Markings And Bills In Birds, Clara Lebow

Electronic Theses and Dissertations

Avian facial plumage, bill coloration, and feather microstructure may serve one or more adaptive functions. Several researchers have proposed that dark eyestripes, bills, and facial masks aid in reducing glare, however, there have been relatively few tests of this hypothesis. Dark facial markings have been shown to have an adaptive glare-reduction function in recent field studies of a few species, but this hypothesis has never been tested in a broad multispecies analysis. It is likely that feather microstructure influences feather brightness and has an effect on the efficacy of glare reduction properties of feathers. I examined the link between dark …


Effects Of Management For Productivity On Adult Survival Of Snowy Plovers, Eleanor P. Gaines, Stephen J. Dinsmore, Michael T. Murphy May 2020

Effects Of Management For Productivity On Adult Survival Of Snowy Plovers, Eleanor P. Gaines, Stephen J. Dinsmore, Michael T. Murphy

Biology Faculty Publications and Presentations

Understanding the factors contributing to variation in demographic parameters and their influences on population growth is fundamental to effective conservation of small populations, but this information is often not available. Among shorebirds, population growth is generally most sensitive to changes in adult survival so understanding the factors affecting this vital rate is important. We used a long‐term mark–resight dataset and Program MARK to examine the effect of management actions, initiated to improve nesting productivity, on adult survival in a threatened population of Snowy Plovers (Charadrius nivosus ) in Oregon, USA. Apparent adult survival averaged 0.71 ± 0.01 (SE), but …


Laying-Sequence Variation In Yolk Carotenoids Of Eastern Bluebirds, Jessica Barkhouse May 2020

Laying-Sequence Variation In Yolk Carotenoids Of Eastern Bluebirds, Jessica Barkhouse

Theses and Dissertations

Carotenoids are naturally occurring, fat-soluble pigments that play an important role in the embryonic development of songbirds. Female songbirds use different strategies to allocate these important maternal resources to their eggs. Little research has been done on whether North American songbirds exhibit laying sequence patterns in their allocation of carotenoids. We studied the laying-sequence variation in yolk carotenoids and egg metrics of nine full clutches of Eastern Bluebirds (Sialia sialis) in Columbus, Georgia. I predicted that Eastern Bluebirds would exhibit a brood reduction strategy, with the first-laid eggs containing a higher concentration of carotenoids than the last-laid eggs. …


Organizational Effects Of Exogenous Corticosterone On Vocal Development In A Wild Parrot, Rory Eggleston May 2020

Organizational Effects Of Exogenous Corticosterone On Vocal Development In A Wild Parrot, Rory Eggleston

Theses and Dissertations

Songbirds learn songs during a plastic phase in vocal development, similar to human vocal babbling. Research has focused on male song learning, a process influenced by gonadal steroids. Like humans, parrots are very plastic vocal learners and both sexes learn vocalizations throughout life. It is unclear how the endocrine system mediates environmental information with developing phenotypes in parrots. Corticosterone (CORT) is a sex-neutral hormone that can affect cognitive development, but its role in vocal development has not been experimentally tested in wild parrots. I quantified vocal babbling from nestling Green-rumped Parrotlets (Forpus passerinus) recorded in Venezuela. Nestlings received oral CORT-oil …


How Water Level And Irrigation Practices Affect Waterbird Community, Nesting, And Foraging Habitat Use On The Duck Valley Indian Reservation, Jamie L. Burke May 2020

How Water Level And Irrigation Practices Affect Waterbird Community, Nesting, And Foraging Habitat Use On The Duck Valley Indian Reservation, Jamie L. Burke

Boise State University Theses and Dissertations

Loss of habitat continues to threaten all bird populations. Despite efforts for conservation of wetlands, waterbirds continue to face habitat threats especially in western North America where water resources are limited across the landscape. The White-faced Ibis (Plegadis chihi) is a colonial nesting waterbird of conservation concern that builds nests in emergent vegetation of freshwater wetlands throughout the western United States. An ibis breeding colony site located at the Blue Creek Wetland complex on Duck Valley Indian Reservation may face habitat threats in the future due to plans intended to increase irrigation water use efficiency. Plans include manipulation …


Several Vegetation Characteristics Affect Reproductive Success Of Grassland Birds At A Restored, Warm-Season Grassland In Central Georgia, Kayla B. Allen Apr 2020

Several Vegetation Characteristics Affect Reproductive Success Of Grassland Birds At A Restored, Warm-Season Grassland In Central Georgia, Kayla B. Allen

Biology Theses

Grassland birds are experiencing major population declines due to habitat loss and fire suppression throughout North America. Large-scale grassland restoration efforts are ongoing, but there is little data on breeding bird productivity on restored habitats, nor on the impact of specific vegetation characteristics on reproductive output. Since 2005, agriculture fields at Panola Mountain State Park, GA have been undergoing restoration to warm-season grasslands; however, up until now there has been no monitoring of nest success or productivity. The goals of this project are to 1) quantify reproductive success and 2) determine which vegetation characteristics are associated with reproductive success. From …


Prey Selection By Birds Of Prey, Anisha Pokharel Apr 2020

Prey Selection By Birds Of Prey, Anisha Pokharel

School of Biological Sciences: Dissertations, Theses, and Student Research

Prey selection is key to determine predator prey interaction and understanding the complexity of food web structure. In this thesis, we used two different approaches to understanding prey selection by North American birds of prey. Using a conventional method, in Chapter 1 we compared pellet analysis and trapping data to assess patterns of prey selection of barn owls in western Nebraska. Microtus spp. comprised 55.8% of the prey items in the barn owl’s diet. The proportion of several prey types in the diet were significantly different from the expected proportion based on trapping. This pattern may indicate barn owls actively …


Seasonal Population Fluctuations In Some Non-Passeriformes At Marala Head, Pakistan, Zahid Bhatti, Asad Ghufran, Fakhra Nazir Mar 2020

Seasonal Population Fluctuations In Some Non-Passeriformes At Marala Head, Pakistan, Zahid Bhatti, Asad Ghufran, Fakhra Nazir

Journal of Bioresource Management

Point count method was used to determine the relative abundance of non-passerine species at Marala wetlands (District Sialkot, Pakistan) during different calendar months between October, 2000 and September, 2001. Six species (Hoopoe, Lapwing, Spotted Owlet, Osprey, Indian Roller and Indian Nightjar) were recorded. Osprey and Spotted Owlet appearing in smaller numbers and Red Wattled Lapwing as a dominant resident. All the species were resident with some variation in population sizes during different seasons, though Osprey was a winter visitor.


Investigating The Avian Species Composition, Diversity, And Abundance Of Engelhorn Pond, Kiana Rose Jan 2020

Investigating The Avian Species Composition, Diversity, And Abundance Of Engelhorn Pond, Kiana Rose

Undergraduate Honors Theses

Central Washington University’s Engelhorn Pond contains important habitats for many organisms, particularly migratory birds, and is a valuable resource for students. However, little information is available about the wildlife inhabiting the pond. The pond’s discrete location means that many people are unaware of its existence. In addition, the pond is threatened by a number of anthropogenic sources, including chemical runoff, garbage, and feral cats. By using point counts, a common ornithological survey technique, I recorded the bird species present at the pond during all seasons of the year. I collected data using point counts during 13 visits from June of …


Phenotypic Divergence In Two Sibling Species Of Shorebird: Common Snipe And Wilson’S Snipe (Charadriiformes: Scolopacidae), Tiago M. Rodrigues, Edward H. Miller, Sergei V. Drovetski, Robert M. Zink, Jon Fjeldså, David Gonçalves Jan 2020

Phenotypic Divergence In Two Sibling Species Of Shorebird: Common Snipe And Wilson’S Snipe (Charadriiformes: Scolopacidae), Tiago M. Rodrigues, Edward H. Miller, Sergei V. Drovetski, Robert M. Zink, Jon Fjeldså, David Gonçalves

School of Biological Sciences: Faculty Publications

Natural and social selection are among the main shapers of biological diversity but their relative importance in divergence remains understudied. Additionally, although neutral evolutionary processes may promote phenotypic divergence, their potential contribution in speciation is often overlooked in studies of comparative morphology. In this study, we investigated phenotypic differentiation in two allopatric shorebirds: the Palaearctic Common Snipe Gallinago gallinago and the Nearctic Wilson’s Snipe Gallinago delicata. Specimens of Common Snipe (n = 355 skins, n = 163 skeletons) and Wilson’s Snipe (n = 403 skins, n = 141 skeletons) in natural history collections were examined to quantify differences in skeletal …


Daily Energy Expenditure Of Florida Scrub-Jays (Aphelocoma Coerulescens) In Suburban And Wildland Landscapes, Hugh I. Ellis, Reed Bowman Jan 2020

Daily Energy Expenditure Of Florida Scrub-Jays (Aphelocoma Coerulescens) In Suburban And Wildland Landscapes, Hugh I. Ellis, Reed Bowman

Biology: Faculty Scholarship

Urbanization alters ecological systems, disturbance regimes, food webs, and a variety of other processes that can influence local flora and fauna. In birds, most studies have focused on behavioral or demographic responses to altered conditions; however, the physiological mechanisms associated with these responses have been understudied. We have previously documented shifts in foraging behavior because of the availability of human-provided food; we sought to see if this was driven by or associated with a change in field metabolic rates. We measured field metabolic rates (FMR), a measure of daily energy expenditure (DEE), of Florida Scrub-Jays (Aphelocoma coerulescens) in 2 habitats …


The Role Of Melatonin In Biological Rhythms Of Songbirds, Clifford E. Harpole Jan 2020

The Role Of Melatonin In Biological Rhythms Of Songbirds, Clifford E. Harpole

Theses and Dissertations--Biology

In vertebrates, melatonin is a hormone that is produced and secreted at night and inhibited by light. This unique “darkness-only” expression profile makes it an intellectually appealing candidate for a means of transmitting temporal information to an individual, both time of day and time of year.

In passerine birds, “time of day” information is certainly transmitted via melatonin secretion. The primary producer of systemic melatonin in this family of birds is the pineal gland, and surgical removal of it causes a bird to become arrhythmic in constant conditions. I find that as pinealectomized house sparrows (Passer domesticus) become …


Energy Content Of Seeds Of Common Sunflowers (Helianthus Annuus) In The Diet Of Scaled Quail (Callipepla Squamata) In Southeastern New Mexico, John L. Hunt, Matthew E. Grilliot, Troy L. Best, Dixie Lozano-Lopez, Emily R. Neilson, Isaac C. Castillo Jan 2020

Energy Content Of Seeds Of Common Sunflowers (Helianthus Annuus) In The Diet Of Scaled Quail (Callipepla Squamata) In Southeastern New Mexico, John L. Hunt, Matthew E. Grilliot, Troy L. Best, Dixie Lozano-Lopez, Emily R. Neilson, Isaac C. Castillo

Journal of the Arkansas Academy of Science

We analyzed the energy content of seeds of common sunflowers (Helianthus annuus) obtained from the crops of scaled quail (Callipepla squamata) collected from plains-mesa sand-scrub habitat in Eddy and Lea counties, New Mexico. Seeds were removed from crops and dried for 48 hours at 60°C to remove moisture and to standardize masses. Seeds were then analyzed for gross caloric value (i.e., energy content) in an oxygen bomb calorimeter. Energy content of seeds of common sunflowers from New Mexico was greater than that of many seeds previously reported from the diet of scaled quail and other granivorous …


The Evolution Of Dragons, Laura J. Mayfield Jan 2020

The Evolution Of Dragons, Laura J. Mayfield

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Dragons have been depicted in human art as early as 4500 BCE. For centuries, these fantasy creatures have inspired countless folk and fantasy tales, as well as appearing in the art of different cultures around the world. Now there are thousands of different depictions of these huge, flying, fire-breathing lizards, but are any of them possible? In this study, I reference peer-reviewed scientific articles, phylogenetic analysis, and paleoart studies to create biologically-sound dragons. Basing the dragon lineage on a real branch of webbed-winged scansoriopterygids—an extinct family of climbing and gliding maniraptoran dinosaurs—I explored the possible wing-structure, fire-breathing abilities, and effects …


Evolutionary Origin And Genetic Diversity Of Ring‐Necked Pheasants In The Upper Midwest United States, Hernán Vázquez-Miranda, Magdalena Jean Olson, Robert M. Zink Jan 2020

Evolutionary Origin And Genetic Diversity Of Ring‐Necked Pheasants In The Upper Midwest United States, Hernán Vázquez-Miranda, Magdalena Jean Olson, Robert M. Zink

School of Biological Sciences: Faculty Publications

We compared mitochondrial cytochrome b sequences of ring‐necked pheasants (Phasianus colchicus) from Midwestern United States (SD and NE, USA) to a molecular phylogeographic hypothesis of pheasants in the native Eurasian range to understand which subspecies are represented by wild and captive released birds. We found that these birds represent 2 Eurasian lineages, which we refer to generally as northern Eurasian (Colchicus group) and eastern China (Torquatus group). These mitochondrial DNA lineages occur in different frequencies in the wild, with the latter being 3 times more common. This suggests that 1) the eastern China lineage is either …


Extreme Offspring Ornamentation In American Coots Is Favored By Selection Within Families, Not Benefits To Conspecific Brood Parasites, Bruce E. Lyon, Daizaburo Shizuka Jan 2020

Extreme Offspring Ornamentation In American Coots Is Favored By Selection Within Families, Not Benefits To Conspecific Brood Parasites, Bruce E. Lyon, Daizaburo Shizuka

School of Biological Sciences: Faculty Publications

Offspring ornamentation typically occurs in taxa with parental care, suggesting that selection arising from social interactions between parents and offspring may underlie signal evolution. American coot babies are among the most ornamented offspring found in nature, sporting vividly orange-red natal plumage, a bright red beak, and other red parts around the face and pate. Previous plumage manipulation experiments showed that ornamented plumage is favored by strong parental choice for chicks with more extreme ornamentation but left unresolved the question as to why parents show the preference. Here we explore natural patterns of variation in coot chick plumage color, both within …


Dynamics Of Avian Elevational Ranges Reveal Hidden Evolutionary Forces, Chauncey R. Gadek Nov 2019

Dynamics Of Avian Elevational Ranges Reveal Hidden Evolutionary Forces, Chauncey R. Gadek

Biology ETDs

The distribution of life across the Andes mountains reflects historical elevational-range contraction and expansion. Whereas contraction implies specialization, expansion requires overcoming hidden barriers. Three eco-evolutionary phenomena may drive patterns in rates of elevational range evolution: (1) The Dobzhansky-MacArthur Phenomenon (DMP) predicts lower rates of upward expansion with harsher physical conditions, while downward expansion increases with lower diversity; (2) the evolutionary tendency toward specialization predicts contraction increases when ranges are broad; and (3) natural selection for respiratory performance could suppress expansion across mid-elevations due to gene-environment mismatch. We modeled elevational range shifts of Neotropical landbirds. Contrary to the DMP, upward expansion …


Wandering Woodpeckers: Foray Behavior In A Social Bird, Sahas Barve, Natasha D. G. Hagemeyer, Russell E. Winter, Samuel D. Chamberlain, Walter D. Koenig, David W. Winkler, Eric L. Walters Oct 2019

Wandering Woodpeckers: Foray Behavior In A Social Bird, Sahas Barve, Natasha D. G. Hagemeyer, Russell E. Winter, Samuel D. Chamberlain, Walter D. Koenig, David W. Winkler, Eric L. Walters

Biological Sciences Faculty Publications

In many cooperatively breeding taxa, nonbreeding subordinates, or helpers, use extra-territorial forays to discover dispersal opportunities. Such forays are considered energetically costly and foraying birds face aggression from conspecific members of the territories they visit. In contrast, breeders in cooperatively breeding taxa are expected to foray seldomly. We used novel tracking technologies to follow 62 acorn woodpeckers (Melanerpes formicivorus), a cooperatively breeding bird, to study extra-territorial foray behavior. Both helpers and breeders engaged in extra-territorial forays routinely and often several times per day. Helpers forayed earlier in the day and invested more time when foraying to high-quality territories. …


Old Enemies With New Problems?: Investigating The Ecological Relationship Between Ridgway’S Hawk And The Parasitic Nest Fly Philornis Pici, Christine Deegear Hayes Aug 2019

Old Enemies With New Problems?: Investigating The Ecological Relationship Between Ridgway’S Hawk And The Parasitic Nest Fly Philornis Pici, Christine Deegear Hayes

Boise State University Theses and Dissertations

Modern conservation efforts tend not to focus on individual species, but rather on the entire ecosystem of a species in peril. Many ecological factors can affect a species’ ability to maintain healthy populations. Parasites, which derive nutrients at the expense of their hosts, can reduce host fitness and limit population growth, acting as biological controls in healthy ecosystems. The negative impacts of parasites on their hosts can be exacerbated by climate change and anthropogenic land-use practices in ways that may limit recovery or drive host species to extinction. Introduced parasitic nest flies in the genus Philornis (Diptera: Muscidae) are threatening …