Ornithology Commons^™

Effects Of Landscape Configuration Metrics On American Barn Owl Nest Box Occupancy And Hunting, Samantha D. Chavez

Cal Poly Humboldt theses and projects

Harnessing ecosystem services, broadly defined as the benefits nature gives to people, is one approach to minimize the widespread negative impacts of agriculture on wildlife and biodiversity conservation. Conservation biological control is one such service that aims to use natural enemies to reduce crops losses from pests without the use of harmful pesticides, including rodenticides. In Napa Valley, California, human-made nest boxes are deployed on wine grape vineyards to attract barn owls (Tyto furcata) that depredate and remove thousands of rodent pests throughout the nesting season. However, the provisioning of this ecosystem service depends on whether a box …

A Return To The Staging Grounds: Reassessment Of Aleutian Cackling Goose Spring Distribution In North Humboldt Bay, Shaun W. Thornton

Cal Poly Humboldt theses and projects

After a 15-year interval in research, spatial and temporal patterns of the Aleutian cackling goose during spring staging was assessed again in 2022. During my study, 3,389 goose flocks were recorded in Arcata Bottoms staging site, 1 January to 21 April 2022, amounting to an estimated total of 2,248,512 goosedays, which was 336.8% higher than 2007 estimates of 667,485 goosedays. Geese continued to use pastures with a wide range of landscape characteristics primarily represented by livestock grazing practices. Goose use was greater than availability on beef-cattle fields early in the season and dairy-cow fields later in the season. Human disturbances …

Winter Sandpiper Communities On Humboldt Bay: High-Tide Roost Use And Habitat Features That Influence Roost Site Selection, Chelsea Polevy

Cal Poly Humboldt theses and projects

Roosts, locations at which birds and other animals come together to rest and preen while remaining vigilant for predators, are a common facet of the nonbreeding biology of many shorebirds. Roosts fall on a continuum from traditional to ephemeral; traditional roosts are used consistently by the same individuals, whereas ephemeral roosts are used inconsistently and may be used only once or a few times. Studies show that roost habitat preference is the result of an individual shorebird’s attempt to optimize the costs and benefits associated with time constraints, energetic demands, and danger risks as they relate to overall fitness.

In …

Knemidokoptes Mites And Their Effects On The Gripping Position Of Steller’S Jay Feet, Wade M. Burris

Cal Poly Humboldt theses and projects

Steller’s jays (Cyanocitta stelleri) with swollen legs and feet resembling the signs of scaly leg have been commonly seen around Arcata, California, USA. These signs are thought to be caused by knemidokoptic mites, a group of parasites specialized at exploiting a range of avian hosts. I compared the gripping position in the feet of jays with variable signs of this condition as an index of their ability to perch, confirmed the presence of mites and identified them to the nearest species using genetic analysis, and compared the relatedness of the cytochrome oxidase subunit I (COI) gene between mites …

The Effect Of Shade Tree Species On Bird Communities In Central Kenyan Coffee Farms, Deven Kammerichs-Berke

Cal Poly Humboldt theses and projects

Shade coffee has been recognized as a well-studied example of a land-sharing management strategy that both creates habitat for tropical birds while also maintaining agricultural yield. Despite the general consensus that shade coffee is more “bird-friendly” than a sun coffee monoculture, little work has been done to investigate the effects of specific shade tree species on bird diversity and their capacity to help deliver ecosystem services. Previous studies in temperate regions have demonstrated that due to shared evolutionary histories, native plant species are better at promoting native arthropod numbers, which in turn support a greater number of birds. This study …

Apparent Survival Of Snowy Plovers Varies Across Years And Between Sexes In Coastal Northern California, Justin A. Windsor

Cal Poly Humboldt theses and projects

Adult survival is one of the most influential vital rates affecting population growth of iteroparous organisms. Survival often varies annually due to environmental stochasticity. However, drastic variations in annual adult survival rates can have overwhelmingly negative impacts on population viability and growth. In many wild avian populations, adult survival varies between sexes and may owe to unequal risks associated with reproductive roles or predation; this is particularly true among shorebirds. I used mark-resight data from a 19-year study of Western Snowy Plovers (Charadrius nivosus nivosus) in coastal northern California to investigate sex-specific apparent survival of the adult population …

Shade Trees Preserve Avian Insectivore Biodiversity On Coffee Farms In A Warming Climate, Sarah L. Schooler

Cal Poly Humboldt theses and projects

Coffee is an important export in many developing countries, with a global annual trade value of $100 billion. Climate change is projected to drastically reduce the area where coffee is able to be grown. Shade trees may mitigate the effects of climate change through temperature regulation for coffee growth, temperature regulation for pest control, and increase in pest-eating bird diversity. The impact of shade on bird diversity and microclimate on coffee farms has been studied extensively in the Neotropics, but there is a dearth of research in the Paleotropics. I examined the local effects of shade on bird presence and …

Apparent Survival Of Snowy Plovers Varies Seasonally, Nora C. Papian

Cal Poly Humboldt theses and projects

Survival is an important vital rate that contributes to population viability, but is infrequently monitored and studied, especially compared to productivity. Furthermore, factors that limit survival and the relative effect on survival are often unknown. I used mark-resight observations of a small (~350) population of threatened Snowy Plovers (Charadrius nivosus nivosus) to quantify seasonal and annual variation in survival and movement between three coastal locations across ~70 km in Humboldt County, California. The return of individuals to non-breeding flocks at three locations was high between years (75-81%). Movement between three locations varied greatly, although most (n = 137) …

The Effects Of Forest Degradation On Dna Methylation In Central African Songbirds, Andrew K. Wiegardt

Cal Poly Humboldt theses and projects

Environmentally-induced stress can initiate a molecular response through DNA methylation, which can alter gene expression, thereby serving as a mechanism allowing individuals to acclimate to a changing environment within their lifetime. In addition to DNA methylation, the production and release of corticosterone is a physiological mechanism by which birds can cope with acute environmental stressors. To assess how environmental stress impacted DNA methylation and corticosterone, I collected blood and feather samples from three understory avian species (Alethe castanea, Bleda notatus and Pseudalethe poliocephala), along a disturbance gradient in the lowland Guinean rainforest adjacent to the village of …

Sex-Specific Habitat Selection Of Rough-Legged Hawks (Buteo Lagopus) Wintering In Western North America, Genevieve Christa Rozhon

Cal Poly Humboldt theses and projects

The rough-legged hawk (Buteo lagopus sanctijohannis) is one of the most under-studied raptor species in North America. As a species that exhibits reversed sexual dimorphism, sex-specific habitat preferences may exist. To investigate rough-legged hawk sex-specific habitat selection preferences, we equipped 17 rough-legged hawks (n = eight females, nine males) with GPS backpacks on their wintering grounds (n = six study areas) during the winter months of 2014 and 2015 in five states in western North America. I analyzed rough-legged hawk habitat selection in relation to sex at four spatial scales: nocturnal roosting site, 50% core range, 95% winter …

Foraging Habitat Of Pileated Woodpeckers In Relation To A Managed Landscape On The Hoopa Valley Reservation, Northwestern California, Dawn Michelle Blake

Cal Poly Humboldt theses and projects

The Pileated woodpecker (Dryocopus pileatus) is associated with older forest stages—larger diameter trees and snags for roosting, nesting and foraging, but they also use managed forests. The Hoopa Reservation is approximately 37,000 ha of mostly forested area with an array of seral stages. The Hoopa Tribe manages timber, and explicitly provides habitat for woodpeckers according to the Tribe’s Forest Management Plan (FMP). No formal study has assessed woodpecker habitat at Hoopa, and habitat has not been well described in this region. I captured eleven woodpeckers and outfitted them with transmitters between 2009 and 2014, and I used resource …

Hunting Habitat Use And Selection Patterns Of Barn Owl (Tyto Alba) In The Urban-Agricultural Setting Of A Prominent Wine Grape Growing Region Of California, Xeronimo A. Castaneda

Cal Poly Humboldt theses and projects

Large scale conversion of uncultivated land to agriculture threatens wildlife and can diminish ecosystem services provided by nature. Understanding how wildlife provision ecosystem services may incentivize wildlife conservation in agricultural landscapes. Attracting barn owls (Tyto alba) to nest on farms for pest management has been documented worldwide, but has not been thoroughly evaluated in vineyard agroecosystems. Napa Valley, California is a renowned winegrape growing region, and viticulturists encourage barn owl occupancy to help minimize plant damage from pocket gophers (Thomomys bottae) and voles (Microtus spp.). This study aimed to establish a basis for revealing the …

Propensity Of Predator Mimicry In Wild Steller's Jays, Trinity C. Tippin

Cal Poly Humboldt theses and projects

Avian vocal mimicry has been described in a variety of contexts, suggesting its function is multifaceted within and across species; however, basic empirical data describing mimetic signal prevalence and context is lacking for numerous species. I examined occurrence and context of mimicked red-shouldered hawk (Buteo lineatus) calls over a 12-month period in a wild population of 49 individually color-marked Steller’s jays (Cyanocitta stelleri) and reviewed the occurrence of the behavior in historic re-sight data. I documented mimicry of red-shouldered hawk calls in 14 of 49 (28.6%) jays during the study. Hawk mimicry occurred more often during …

Mobbing Behavior In Wild Steller's Jay (Cyanocitta Stelleri), Kelly Anne Commons

Cal Poly Humboldt theses and projects

Mobbing is a widespread anti-predator behavior with multifaceted functions. Mobbing behavior has been found to differ with respect to many individual, group, and encounter level factors. To better understand the factors that influence mobbing behavior in wild Steller’s jays (Cyanocitta stelleri), I induced mobbing behavior using 3 predator mounts: a great horned owl (Bubo virginianus), common raven (Corvus corax), and sharp-shinned hawk (Accipiter cooperii). I observed 90 responses to mock predators by 33 color-marked individuals and found that jays varied in their attendance at mobbing trials, their alarm calling behavior, and in …

Molt In Individuals: A Description Of Prealternate Molt Phenology In A Population Of Snowy Plovers In Humboldt County, California, Alexa Dejoannis

Cal Poly Humboldt theses and projects

Molt in birds is an essential physiological process. Intrinsic and extrinsic conditions, such as age, sex, location, or food stress, may cause individual variation in molt phenology. This study describes the timing of prealternate molt in western snowy plovers (Charadrius nivosus nivosus) wintering in Humboldt County, California, USA. Between July 2014 and April 2015, I photographed uniquely marked plovers twice a month and assigned dates of initiation and completion. I modeled sex, age, hatch date, and breeding location as predictors of molt phenology. I observed prealternate molt from October to April, which is earlier than previously described. Males …

An Experimental Test Of Response By Common Ravens To Nest Exclosures, Teresa R. King

Cal Poly Humboldt theses and projects

Common ravens (Corvus corax) are intelligent generalists and a principal predator affecting population recovery of several threatened and endangered species, including the threatened western snowy plover (Charadrius nivosus nivosus). In Humboldt County, raven predation is a primary cause of low nest survival. Nest exclosures, cages around eggs that preclude entry by predators but allow plovers access to incubate, are known to increase nest success. However, speculation exists that exclosures may attract predators. The aims of this study were to summarize corvid distribution on Clam Beach County Park and Little River State Beach, evaluate habitat features associated …