Ornithology

Posters

 
Spatial and Temporal Drivers of Wetland Bird Occupancy in An Urbanized Matrix
Anastasia Rahlin, Sarah Saunders, Stephanie Beilke
Wetland birds are undergoing rapid declines in North America, with habitat degradation and wetland loss considered primary causes of declines. Due to the cryptic nature of many wetland bird species, the ecological factors and relevant spatial scales affecting wetland bird occupancy and habitat use remain unclear. We conducted surveys at 477 points across northeast Illinois and northwest Indiana, using the Standardized North American Wetland bird Monitoring Protocol. Wetlands surveyed were located primarily in the highly urbanized landscape of Chicago. Using remotely-sensed data, we built occupancy models for 10 wetland bird species to quantify their responses to wetland cover types (emergent wetland, forested wetland, riverine wetland, freshwater pond) and urbanization at four spatial scales (200 m, 400 m, 800 m, and 2000 m radial distances). Species varied in their responses to wetland cover, urbanization, and distance from Lake Michigan. Occupancy for all species remained stable during the three-year study period. Presence of emergent wetlands and ponds at local and immediate scales increased wetland bird occupancy. Contrary to expectations, increasing urbanization did not negatively affect wetland bird occupancy for most focal species. Urban wetland restoration should focus on restoring emergent vegetation and ponds at local scales. More research is needed to evaluate management strategies at the watershed scale.
 
Common Ravens Disrupt Greater Sage-Grouse Lekking Behavior in the Great Basin
Mark Ricca, Joseph Atkinson, Peter Coates, Brianne Brussee, Ian Dwight
Expansion of human enterprise has contributed to increased abundance and distribution of common ravens (Corvus corax; hereafter, raven) across sagebrush ecosystems within western North America. Ravens are highly effective nest predators of greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse), a species of high conservation concern. Sage-grouse population trends are estimated using count survey data of males attending traditional breeding grounds, known as leks. We sought to investigate associations of ravens to sage-grouse lek sites and document interactions between the sage-grouse and ravens, as well as predators of adult sage-grouse. First, we used extensive raven point counts and lek count data collected across Nevada and California to evaluate spatial associations between sage-grouse and ravens while accounting for other environmental covariates. We found that ravens were more likely to be observed closer to lek sites, especially as leks increased in size. Second, we used a subset of the lek dataset to describe behavioral changes of male sage-grouse in the presence of ravens and other predators. While golden eagles (Aquila chrysaetos) and other raptors elicited stronger disruptive responses, our models indicated ravens also decreased the probability of sage-grouse displaying and increased the probability of sage-grouse flushing from leks. These results collectively suggest that sage-grouse perceive non-lethal ravens as a reason to alter breeding activity, and lek counts could be biased low if raven presence during surveys is not accounted for when used in modeling trends in population abundance. Findings are preliminary and provided for timely best science.
 
Assessing the Ability to Establish and Maintain Eastern Purple Martin Colonies Within Managed Working Forests
Jami Nettles, Joe Siegrist, Daniel Greene, Scott Rush, Blake Grisham, James D. (Jim) Ray
Many long-distance avian migrants breeding within North America are declining, with loss of nesting areas and prey implicated as contributing factors. Today, the eastern subspecies of Purple Martin (Progne subis subis) nests almost exclusively in housing provided by citizen scientists who erect structures specifically for these birds. Working forests of the U.S. cover nearly 180 million ha of the eastern U.S. and provide essential early successional conditions that support rich species diversity, including avian and invertebrate communities. Given the continuing decline of Purple Martins, we sought to evaluate the feasibility of establishing and maintaining colonies within open canopy stands of managed forests, while enticing their use of nearby natural cavities. In January 2020, we erected nine gourd racks throughout a contiguous 25,000 ha block of Loblolly Pine (Pinus taeda) forests in Noxubee and Kemper Counties, Mississippi. That year we had no signs of activity during most of the breeding season, but in July, the area around one rack became a pre-migratory roost site with approximately 65 individuals. Unexpectedly, some birds constructed nests, and that month we banded eight fledglings from three nests and observed signs of occupancy in two adjacent structures. In 2021, at least eight individuals returned to the structure occupied in 2020, and by May, three nests contained eggs. Evidence obtained from isotopic analysis (δ13C, δ15N) of blood sampled from fledglings in 2020 and primary producers and insects sampled within the study area suggest that these birds assimilated aerial insects not specifically from wetlands or riparian buffers. Rather, these birds likely consumed aerial insects captured across managed open canopy stands fostered by high C3 and C4 primary productivity. To our knowledge, these are the first purple martins born in a working forest, supporting evidence that working forests provide conservation opportunities for this species and other colonial-nesting, insectivorous birds.
 
Hemoparasite Prevalence and Diversity in Rocky Mountain Hummingbirds
Braden Godwin, Berit Bangoura, Holly Ernest, Megan Dudenhoeffer, Adrienne MacKenzie, Ravinder Sehgal, Lisa Tell
Hummingbirds (Trochilidae) have a unique physiology with a high metabolic range and the highest red blood cell levels found in any vertebrate animal. These physiological attributes cause hummingbirds to be especially sensitive to environmental changes, making them an important indicator species. Additionally, hummingbirds may be uniquely affected by hemoparasite (blood parasite) infections. Thought to be transmitted by dipteran vectors, most research on hemoparasites in hummingbirds has taken place in South America and little is known about hemoparasite diversity and prevalence in North America. In the Rocky Mountain ecosystem of the western USA, Broad-tailed Hummingbirds (Selasphorus platycercus) are important wildflower pollinators. The presence and diversity of hemoparasites in this species has not yet been explored. We sought to determine if hemoparasites were present in Rocky Mountain Broad-tailed Hummingbirds, and to determine the prevalence and diversity of any detected hemoparasites. We used blood samples collected from 314 hummingbirds across 25 sites in Colorado and Wyoming. Blood samples were screened for hemoparasites using microscopy (N = 311) and PCR (N = 301). PCR positive samples were sequenced at the cytochrome b lineage for hemoparasite identification. Both diagnostic techniques detected the genus Haemoproteus in the same 5 samples, with an overall prevalence of 1.6% when both methods were combined. We detected Haemoproteus in 3 female and 2 male adult hummingbirds. No Plasmodium or Leucocytozoon hemoparasites were detected. Our study provides the first report of the prevalence and diversity of hemoparasites in Broad-tailed Hummingbirds in the Rocky Mountains.  
 
Behavioral Response of Native Birds to a Novel Competitor That Utilizes Nest Predation – SRIP
Daniel Baron, Olya Milenkaya, Lindley McKay
Invasive species can cause changes in their new range, including changes to the community structure, community dynamics, and interspecific interactions. Invasive House Wrens (Troglodytes aedon) out-compete naïve birds for limited nesting cavities by killing their eggs and nestlings. This nest-site competition through predation places intense selective pressure on Carolina Chickadees (Poecile carolinensis) in areas of recent contact between the two species, such as western North Carolina, USA. Here, Carolina Chickadees nesting near House Wrens shift their reproductive strategies in a way that reduces the cost of House Wren predation. However, the mechanism for this shift in reproductive strategy is unclear and it is not known if they recognize House Wrens as a threat. This study will determine how Carolina Chickadees respond to House Wren intrusion near their nests, which will indicate whether they recognize them as a threat. We monitored 106 nest boxes for Carolina Chickadee nesting beginning in March 2021. We are using point counts to determine if House Wrens are present at each nest. We are then conducting a within-subject experiment to compare the behavior of Carolina Chickadees in response to simulated intrusions near their nest by three species in a randomized sequence. These species treatments include: a long-established nest predator (positive control), a long-established non-threatening species (negative control), and the newly-established House Wren (experimental treatment). During each trial, we place a taxidermy model and play vocalizations of the model species near the nest for five minutes. Two observers then record the approach distance by each Carolina Chickadee to the model every 5 seconds. Songbirds approach threatening species, and we will interpret a closer approach as indicative of Carolina Chickadees recognizing House Wrens as a threat. We will compare the approach distance between the three treatments, as well as between those nesting with and without House Wrens present.
 
Phenology and Productivity of An Avian Community in Gambel Oak – SRIP
Bryce Cowan, John Cavitt
Conservation of avian species relies on the identification and preservation of habitat conditions that sustain healthy populations of coexisting species in which productivity is adequate to maintain population size. Currently, avian communities of Gambel oak (Quercus gambelii) are not well understood. This in-progress study seeks to identify current population levels, determine the phenology of the arrival of individuals on site by age class, and to quantify the productivity of the population within one such community in northern Utah. Data was collected through mist-netting and banding of individuals in habitat comprised predominantly of Gambel oak during the winter seasons of 2019 – 2020 and 2020 – 2021. The results and conclusions for the in-progress presentation will focus on the three most common species banded at the site: Oregon junco (Junco hyemalis montanus), house finch (Haemorhous mexicanus), and black-capped chickadee (Poecile atricapillus). However, it is the goal that productivity and age ratios will eventually be reported for all species banded at the site after having at least a full year of banding that includes a breeding season.
 
Can Avian Museum Specimens Guide Conservation Interventions by Estimating Population Connectivity? – SRIP
Morgan Dean, Brian Weeks
Understanding dispersal has important applications for the management and conservation of species in the context of increasingly fragmented landscapes. However, directly measuring dispersal rates is difficult for many species, making it challenging to prioritize habitat restoration to improve connectivity among populations of species that are dispersal-limited and thus most vulnerable to the effects of habitat fragmentation. In birds, the application of standard methods of quantifying avian dispersal ability, such as satellite telemetry and mark-recapture techniques, is difficult at large scales. To overcome this challenge, macroevolutionary studies that focus on avian dispersal often use the hand-wing index (HWI), a biometric index of avian flight efficiency based on the aspect ratio—or pointedness—of a bird’s wing that has been estimated for all bird species. A specific application of HWI can be observed in its potential to inform conservation efforts by effectively predicting gene flow among populations, a key determinant of population persistence. Focusing on this application, we hypothesize that avian species with lower dispersal ability will have greater genetic divergence between populations. Using a mixed modeling framework, we test this hypothesis by predicting mitochondrial differentiation (FST) across barriers for different species as a function of HWI while controlling for attributes of the landscape. Should HWI accurately predict population connectivity, it can be a powerful tool for prioritizing restoration efforts to improve landscape connectivity in avian conservation management.
 
A Comparison of Sparrow Diversity in Northeast Texas – SRIP
Emily McGhee, Heather A. Mathewson, Kathryn Burton, John Palarski
Populations of North American grassland sparrows have dramatically declined over the past 200 years. Habitat loss and fragmentation continue to occur, which adversely affects sparrow populations and sparrow diversity. In addition, there is little knowledge of wintering sparrow habitat since most research has focused on the breeding grounds. Previous studies suggest that sparrow occurrence highly correlates with vegetation structure. Therefore, the objective of this study is to determine what types of vegetation structure supports higher sparrow diversity on a 2,691 ha military base in Lamar County, Texas. We created 20-m x 100-m transects using a stratified random sampling approach across post oak savanna vegetation communities to survey wintering sparrows from 3 December 2020 – mid-March 2021. We used a double observer flushing technique and recorded all sparrow species observed. We measured fine-scale vegetation structure and species composition using Daubenmire frames and the line-intercept method in March 2021 along sparrow survey transects. We calculated mean vegetation measurements by averaging data collected at all survey transects. We will use the Shannon Diversity Index to measure sparrow species diversity and AIC model selection to determine what vegetation metrics best predict diversity. Our findings will help us better manage grassland ecosystems in a way that supports the specific vegetation components required for greater sparrow use and diversity.
 
Using Acoustic Spatial Capture-Recapture to Estimate Owl Population Density and the Effects of Anthropogenic Noise in the Chattahoochee River National Recreation Area, Georgia – SRIP
Lily Martin, Jeffrey Hepinstall-Cymerman, Richard Chandler, Michael Parrish, Robert Cooper
Passive acoustics may offer advantages over traditional survey methods for estimating population trends of cryptic species that are difficult to monitor. Acoustic studies incorporating spatially explicit capture-recapture (SECR) methods have successfully estimated population density of various taxa. However, these methods have seldomly been applied to avian species, though previous studies demonstrated estimates from acoustic data were more precise than those obtained from mist-netting. We are using acoustic SECR to estimate the population density of Barred Owls (Strix varia), Eastern Screech-Owls (Megascops asio), and Great Horned Owls (Bubo virginianus) in the Chattahoochee River NRA, GA. We will also investigate the relationship between owl density and anthropogenic noise associated with extensive urban development in the study area which may threaten avian populations, but its effects are not yet well understood. The study could have important management implications for urban areas where owls persist if individuals must avoid areas of otherwise suitable habitat.
 
Female Veery Flight Distance from Nest during Nest Building Process in Massachusetts – SRIP
Brianna Herforth
This project will investigate how far female Veeries (Catharus fuscescens) travel from their nests, during nesting season, using radio telemetry in a specified research area. Since the elevation in Massachusetts varies, exotic scrubs that Veeries build nests with is dispersed (Merow, 2017).  The distribution of invasive and native plants may be impacted by a changing climate. This result may change the way Veeries use their breeding habitats. This project will provide data on female Veeries during their nesting period. The goal of this project is to investigate the distance female Veeries travel from their nest during nesting season in Western Massachusetts. The research area is recreational, located in a one km2 section within the forest around Windsor Lake Park and MCLA Forest in North Adams, Massachusetts. As radio telemetry is unable to provide an exact location, global positioning system (GPS) locations will be used. The proposed hypothesis states that female Veeries will not travel further than fifty meters from respective nest during nesting season. As these birds construct their nest in three stages with shrub this will provide how far these birds are traveling for materials (Heckscher, 2014). References Heckscher, C., & Taylor, S. (2014, January 1). Veery (catharus FUSCESCENS) Nest architecture and the use of alien plant parts. Retrieved April 11, 2021, from https://bioone.org/journals/The-American-Midland-Naturalist/volume-171/issue-1/0003-0031-171.1.157/Veery-Catharus-fuscescens-Nest-Architecture-and-the-Use-of-Alien/10.1674/0003-0031-171.1.157.shor Merow, C., Bois, S., Allen, J., Xie, Y., & Silander, J. (2017, April 18). Climate change Both facilitates and Inhibits invasive plant ranges in New England. Retrieved April 11, 2021, from https://www.pnas.org/content/114/16/E3276.short
 
Northern Cardinal’s Range Expansion as a Result of Supplementary Feeding – SRIP
Jenna Brewer, Jared Wolfe, Kristin Brzeski
The Northern Cardinal has experienced range expansion across the northern reaches of its distribution despite climate change and urbanization. The availability of bird feeders has been implicated in the cardinal’s northward expansion, as supplemental feeding may sustain populations over the winter months when natural food sources become scarce. To determine if the cardinal’s dietary flexibility facilitated the exploitation of supplementary food resources, we will conduct isotopic and DNA metabarcoding analyses on cardinal feathers and fecal samples collected across the species range to examine variation in dietary breadth as a function of season and latitude. Our study aims to identify the behavioral mechanisms responsible for a species population growth in an era characterized by biodiversity loss.   To execute our analysis we will use mist-nets to capture, band, and collect samples from cardinals in Houghton, Michigan, while our numerous collaborators, from Florida to Upstate New York, will simultaneously be collecting the same data from their respective population of  cardinals. After adequate samples are procured, we will run isotopic analyses on feathers collected across the summer and fall seasons, from locations throughout the cardinals’ range, to compare ratios of nitrogen and carbon isotopes and determine dietary changes across the expansion front. Furthermore, we will employ DNA metabarcoding to examine dropping samples and discern dietary composition in more detail.  Given the potential importance of food supplementation to expanding populations of cardinals, we predict that cardinals in the northern reaches of their expansion front will exhibit winter diets dominated by seeds rather than insects, when compared to their southern counterparts. However, during summer months when insects are readily abundant in most latitudes, cardinals will display similar dietary patterns throughout their range.   
 
Simulation Model of Bird Availability and Detectability to Identify Point Count and Occupancy Modeling Recommendations for Evening Surveys – SRIP
Kevin Shaw, Paige Ferguson
Given declines in abundance and modern threats to bird species, it is imperative that ornithologists perform accurate occupancy studies for effective management and conservation decisions. Currently, morning point count surveys are standard for studying breeding birds, but evening peaks in avian activity present another possible survey occasion. We aim to evaluate the accuracy and precision of evening occupancy probability estimates under various avian availability and detectability scenarios to make recommendations for survey or modeling methods. We simulated detection histories decomposing the probability of detection given occupancy (p) into two components: probability of a species being active and available for detection given occupancy (availability; s), and probability of detection given occupancy and availability (detectability; d). We simulated scenarios with different combinations of constant high, constant low, or site-varying occupancy; constant high, constant low, or site- and survey- specific availability (s); and constant high, constant low, or site- and survey-specific detectability (d). We also simulated scenarios in which morning availability and/or detectability values either equaled or differed from those in the evening. We used JAGS to produce posterior distributions for occupancy (psi) and detection (p) probabilities and measured the degree of overlap between morning and evening posterior distributions, bias between values used to simulate data and posterior means, and 95% Bayesian credible interval precision. Occupancy posterior distributions were less precise in the evening surveys when availability and/or detectability were low in the evenings but high in mornings. Models including all covariates used to simulate data were unbiased in both mornings and evenings even with low and variable parameters. Our next step is to test scenarios where covariate(s) used to simulate data are excluded from the inference model. Understanding the circumstances that lead to accurate or biased, precise or imprecise evening posterior distributions will inform recommendations about survey and occupancy model application.
 
Increased Incidence of Neurological Abnormalities in Passerines and Near Passerines Through Seven Years of Avian Rehabilitation in Wisconsin – SRIP
Melinda Houtman, Shelli Dubay, Marge Gibson, Jackie Sandberg
During the summer of 2020, staff at Raptor Education Group Inc., an avian rehabilitation center in Antigo, Wisconsin noticed a drastic increase in songbirds admitted showing signs of neurologic disorders. I conducted an analysis of seven years of patient records to determine trends of neurologic cases in birds of the orders Passeriformes, Apodiformes, Caprimulgiformes, Cuculiformes, and Piciformes. I ran a chi square test on the data from Raptor Education Group and results suggest a significant increase in neurologic abnormality cases in 2020 compared to previous years (X2 0.05,1 = 25.8, p < 0.001, N = 2893). The objective of this project is to determine if a similar trend occurred in Dane County and identify possible reasons for this trend. I gathered data from the Dane County Humane Society’s Wildlife Center in Madison, Wisconsin to include in the analysis. Data from Dane County Humane Society will be analyzed like that from Raptor Education Group and the two locations will be compared to determine if the trend of increased neurological abnormalities was seen in multiple locations in the state.

Posters
Location: Virtual Date: November 4, 2021 Time: 11:00 am - 12:00 pm