TWEL Current Research

TWEL Current Research

Population Demographics and Stable Isotope Evaluation of the North American River Otter in Ohio

Sara Adamczak, M.S. Candidate


Advisor: Stanley D. Gehrt


In Ohio, river otters were extirpated by the 1950s, reintroduced in 1986, and otter trapping was reinstated in 2005. Preliminary work indicated that the river otter population in Ohio was large and increasing prior to the reinstatement of river otter trapping in 2005, thereby indicating that river otter trapping from 2005-2008 was sustainable. These preliminary estimates, however, lack specificity in terms of variation among sex and age classes. While the river otter harvest seems sustainable, considerable changes could be occurring in the demographics of the river otter population in Ohio. If there are temporal or spatial variations in the river otter population demographics, then population models based on previous demographic data might not represent the current population or the impact of the current harvest. This strengthens the need to do a reexamination of river otter abundance and the impact of harvest on populations. This project will help fill in knowledge gaps and update river otter demographic data, ensuring a healthy and sustainable population. With the addition of stable isotope evaluation, diet composition and prey availability will be determined within the study areas, possibly explaining movement, home ranges and more!

Sara Adamczak

Project Support: Ohio Division of Wildlife

Eastern Massasauga Rattlesnake: Ohio Population Survey and Survey Technique Development

Evan Amber, M.S. Candidate

Advisor:  William Peterman  


Evan's thesis, supported by The Ohio Department of Transportation, is to modify and test the Adapted-Hunt Drift Fence Technique as a non-invasive and cost-effective alternative survey method for the endangered eastern Massasauga rattlesnake in northeastern Ohio. With our adaptation of this method, developed by Martin et al. in 2017, snakes will be guided along a Y-shaped drift fence to inverted buckets containing a camera trap.

TWEL Evan Amber

Funded by: The Ohio Department of Transportation


Filling in the Gaps for Full Annual Cycle Conservation of the Prothonotary Warbler: Phenology, Post-Fledging Survival, and Links to the Winter Grounds

Elizabeth M. Ames, M.S. Candidate

Advisor:  Christopher Tonra  

Summary: Every year thousands of birds migrate between the breeding grounds, in temperate North America, and the wintering grounds in tropical Central America. Many of these Neotropical migrants complete the various stages of their annual cycle thousands of kilometers apart, and events in one of these stages can effect events in a subsequent stage. Understanding these “carry-over effects” is fundamental to understanding changes in migratory populations and the conservation of those populations, as many are in enigmatic decline. The objective of my research is to explore carry-over effects between wintering and breeding events, and elucidate an unexamined life-cycle stage in a migratory bird of conservation concern, the Prothonotary Warbler (Protonotaria citrea). My research will take place across the Hoover Nature Preserve which hosts the largest breeding population in Ohio. There, I will examine three important aspects of their ecology to test the hypothesis that carry-over effects from winter habitat limits post-fledging survival through impacts on arrival and breeding timing. First, I will determine if arrival timing to breeding grounds is winter habitat dependent using stable isotopes in bird claws to estimate winter habitat wetness and thereby quality. Second, I will track breeding timing and fledging success relative to arrival time and winter habitat quality. Lastly, I will use radio telemetry to estimate post-fledging survival as a function of phenology and winter habitat quality. My research will fill important gaps in the ornithological knowledge of the Prothonotary Warbler’s full annual cycle and guide forested wetland bird conservation across the Americas.

Funded by: The Ohio State University, OARDC SEEDS Grant, Columbus Audubon, Explorer's Club, Association of Field Ornithologists, Ohio Avian Project Initiative, USFWS.


The Impact of Amur Honeysuckle (Lonicera maackii) Removal on Avian Assemblage Composition

Leanna DeJong, M.S. Candidate


Advisor: Stephen N. Matthews


In recent decades, both coyotes and white-tailed deer have expanded their range into urban environments. Although both of these species are studied extensively, little is known about how coyotes influence deer behavior in urban environments. As the top predator for many urban landscapes, coyotes can potentially affect the movement and resource use of lower trophic species. I aim to identify whether coyotes impact vigilant foraging behavior and habitat use of deer in the Chicago metropolitan area. This research will focus on two antipredator behaviors, “vigilance” and “avoidance”, to determine if and how deer alter their behavior with indication of coyote presence. How these behaviors differ between sexes, age classes, and group sizes of deer, as well as how vigilance and avoidance change seasonally will also be investigated. This study aims to shed light on the relationship between these two species as well as the variances in antipredator behavior of deer in an urban environment.

TWEL Current, DeJong


Population Ecology, Habitat Relationships, and Survey Methodology of Sora and Virginia Rails in Northwestern Ohio 

James Hansen, M.S. Candidate

Advisor: Robert Gates  
Summary: The amount of wetland habitat across North America has declined heavily over the last century. The Virginia rail and sora are two species of wetland-dependent birds that are part of a guild of birds known as secretive marsh birds that inhabit wetlands across the United States and Canada. Populations of secretive marsh birds are thought to have been declining and negatively impacted by the monumental wetland loss across the North American continent. However, the populations status of many secretive marsh bird species is not well understood due to their cryptic behavior and the densely vegetated habitats they occupy. In 2011,  the North American Marsh Bird Monitoring Protocol was established to survey and monitor secretive marsh birds across the continent, however, concerns over the limitations of this survey have arisen due to these birds’ low detectability, variable calling rates, intra-seasonal movements, and a number of other factors.  I aim to test this survey and investigate the relationship between rail population ecology and bird movements, calling behavior, and fluctuations in environmental variable.  This research will provide modifications for the marsh bird survey in an Ohio context and help inform wildlife managers on the implications of harvest regulations and wetland habitat management for the Virginia rail and sora.
Funding Source: Funding  provided by the Federal Aid in Wildlife Restoration Program (W-134-P, Wildlife Management in Ohio), and administered jointly by the U.S. Fish & Wildlife Service and the Ohio Division of Wildlife.  


Response of Early Successional Avifauna to Pipeline Right-of-Way Vegetation Management in Eastern Ohio

Lewis Lolya, M.S. Candidate

Advisors:  Stephen Matthews & Gabriel Karns  

Summary: Early successional bird species have exhibited population declines across Ohio, coinciding with a state-wide loss in young forest and shrub-scrub habitats. Additionally, forest fragmentation and land use conversion has increased with accelerating shale gas development. Pipeline right-of-ways, which represent the largest proportion of the shale gas footprint, hold potential for early successional habitat management. This potential has been demonstrated for analogous electric right-of-ways, but minimal research is available for corridors with underground infrastructure. My research goals focus on understanding early successional avian response to forest edge-cutback techniques along pipeline ROWs and understanding avian utilization of the pipeline-forest interface. I am utilizing avian point counts, nesting surveys, and vegetation sampling to monitor changes over time of habitat structure and breeding bird utilization of the pipeline-forest interface at several pipeline study sites in eastern Ohio. Additionally, I am monitoring the nesting success of breeding birds on the forest-pipeline ecotone to understand the nesting success and productivity within these heavily modified forests. Early successional forest management on pipelines corridors has the potential to meet habitat conservation goals outlined by the Ohio All-Bird Conservation Plan for declining bird species in Ohio, such as the yellow-breasted chat (Icteria virens), blue-winged warbler (Vermivora cyanoptera), and brown thrasher (Toxostoma rufum). Because shale gas infrastructure occupies substantial land use area in the Appalachian region of Ohio, the development and adoption of conservation minded management practices for these lands has the potential to produce positive environmental change at the landscape level. This management oriented research is interdisciplinary, and requires close partnerships between numerous stakeholders, including private landowners, energy and shale gas entities, and conservation organizations.

Funding Source:  Ohio Department of Natural Resources: Division of Wildlife, Bayer Feed-A-Bee Initiative, and Monarch Joint Venture  



Demographics and distribution of the Northern bobwhite and other birds of early-successional habitat

Connor J. Rosenblatt, M.S. Candidate

Advisors: Stephen N. Matthews and Robert Gates  

Birds of early-successional habitat are one of the most rapidly declining groups of birds across North America. This is primarily due to the loss of young-forest and shrubland habitat. In eastern North America, habitat loss has been primarily due to processes such as regeneration of mature forests, altered disturbance regimes, and agricultural intensification. One particular shrubland bird of conservation interest is the Northern bobwhite (Colinus virginianus). Across their range, bobwhites have been declining at an alarming rate for the past several decades. Declines in Ohio have been particularly acute, and research has found that these populations suffer high winter mortality during periods of extreme snowfall. Given the social and economic importance of the bobwhite as a gamebird species, much effort and support has been given towards bobwhite conservation, yet despite this, populations in Ohio continue to decline. My project is focused into two components. First, in order to help inform managers on the most effective way to manage bobwhite populations, I seek to employ a novel population modeling technique known as integrative population modeling. Utilizing existing data on abundance and life-history demographics, I seek to model bobwhite population dynamics and relate this to weather and habitat covariates. Doing so will allow me to predict the future population growth rate and understand which aspects of the bobwhite’s annual life cycle have the greatest influence on the population growth rate. Given projected future climate change, understanding the relationship between demographic parameters, weather, and population growth will be crucial for effective bobwhite management in a changing future. The second part of my project is focused on examining the relationship between landscape characteristics and the distribution of other early-successional birds in areas where bobwhites persist. Previous work has suggested that, because of their need for a heterogenous landscape, managing land for bobwhites may benefit other non-target shrubland bird species with similar habitat requirements. Because of their broad habitat requirements and the amount of conservation attention they receive, bobwhites have potential to serve as an umbrella species for a whole suite of early-successional birds. Thus, in order to assess the potential for this, I will be seeking to model the relationship between bird distributions and various components of landscape composition and configuration. I will be focusing on landscapes in southern Ohio where bobwhites are present, and examining whether the presence of bobwhites is a predictor for the presence of other bird species, and how both of these measures are related to landscape characteristics. Ultimately, I hope the findings from my project can help inform managers across the state as to how to better manage early-successional habitat for multiple species of conservation concern.

TWEL Current, Rosenblatt

View completed projects here.