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


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.


Impacts of Coyotes (Canis latrans) on White-tailed Deer (Odocoileus virginianus) behavior and mortality in the Chicago Region

Gretchen Anchor, M.S. Candidate


Advisor: Stanley D. Gehrt


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.

Gretchen Anchor


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  


Monitoring Tree Species Change in Oak Forests

Donald Radcliffe, M.S. Candidate

Advisors: Stephen N. Matthews and David Hix  
Oak forests are gradually being replaced by maple forests across the eastern U.S., in a process known as mesophication.  Mesophication is a complex phenomenon likely caused by multiple changes on the landscape.  The most important is probably fire suppression, which started about a century ago in most of the U.S.  Other likely drivers of mesophication include more atmospheric nitrogen deposition, more whitetail deer, and a wetter climate during the past century.  Oaks are important for most forest wildlife species in Ohio - acorns are a vital source of winter food for many animals, oak leaves probably host more insects than most tree species, most migrating birds prefer to forage on oaks over maples, and oaks can tolerate cavity formation without dying, so they’re more likely to host cavity nesters.  In order to measure change in oak forests over time, I’m revisiting a series of permanent plots that were first establishing by David Hix on the Marietta Unit of the Wayne National Forest in the mid-1990’s.  I’m specifically asking whether oak forests will maintain themselves on dry south and west facing aspects, or whether they will need management intervention to prevent them from becoming maple forests, even on sites that are thought of as favorable.  These data are crucial to managers that want to keep a component of oak in their forests, and thus improve the wildlife habitat found therein.   Donald Radcliffe
Funding Source:  OARDC SEEDS Grant  


View completed projects here.