SCHUYLKILL HAVEN, Pa. — At a regional conference, recent Penn State graduate Joseph Medica and rising senior Bethany Hollenbush, both past and current biology majors at the Schuylkill campus, and Lucas Redmond, assistant professor of biology at Penn State Schuylkill, have recently presented findings of their research at a regional conference. The multi-year research project, focused on the gray catbird population located on and adjacent to the campus was presented at the 2021 Northeast Natural History Conference, hosted in conjunction with the Wilson Ornithological Society and the Association of Field Ornithologists’ annual meetings.
Hollenbush and Medica each delivered poster presentations, and Redmond, the students’ faculty adviser, also delivered a talk at the conference.
Nest success and nest-site characterization in gray catbirds
Hollenbush’s presentation, “Nest Success and Nest Site Characterization in Gray Catbirds,” reviewed the birds’ nest-site selection and success in a population of catbirds located on and around campus. The field research was conducted during the gray catbirds’ breeding seasons from early to mid-May through late May and early June between 2016 and 2019.
Once the catbirds arrived at the study site, the research team conducted daily surveys of the area to locate as many breeding pairs of birds and their nests as possible. Once they located these nests, they would check in on them every three to four days to determine if the nests were successful or had failed.
After nest fate was determined, nest-site surveys were conducted to measure characteristics of the nest site and its surrounding habitat, including height and diameter of shrubs where nests were placed, nest height, orientation, concealment, and canopy area.
The researchers employed the program MARK, which provides parameter estimates from marked animals when they are re-encountered later, to estimate daily survival rates and understand how nest success varied. Across the period of this study, approximately 47% of catbird nests were successful, and their MARK analysis indicated that daily survival rates of catbird nests varied yearly and tended to decline as the breeding season progressed.
Hollenbush’s presentation also examined the type of vegetation in which the catbirds constructed their nests. “Our characterization of nest sites indicated that catbirds on our study site primarily utilized three species of invasive woody shrubs: multiflora rose, Tartarian honeysuckle, and privet,” she said in her presentation abstract. “Nest height exhibited some difference among these three species, with nests placed in privet being higher than those in rose, while nests in honeysuckle were intermediate in height. Aside from these findings, we found no other consistent differences in nest placement among the three species of shrub used.”
This presentation earned Hollenbush a finalist designation in the conference’s student poster competition. “Although I was nervous about presenting to people much more experienced than myself, my poster received great comments from the judges. That conference was good practice for my next presentation at the American Ornithological Society in August,” she said.