Jen Owen

Associate Professor of Fisheries and Wildlife | Michigan State University

East Lansing, MI, UNITED STATES

Wildlife expert, focusing on the role of wild birds in the maintenance, transmission and spread of pathogens

Biography

Jen Owen's research efforts investigate the role of wild birds in the maintenance, transmission and spread of pathogens such as avian influenza and West Nile virus. Her work also aims to understand how the demands and stress of the migratory period influence a bird's immune system.

Industry Expertise (4)

Environmental Services

Education/Learning

Research

Writing and Editing

Areas of Expertise (2)

Behavioral Ecology of Migratory Birds

Ecology of Zoonotic Diseases

Links (1)

Google Scholar Citations

Journal Articles (3)

Exotic-and native-dominated shrubland habitat use by fall migrating Swainson's Thrushes and Gray Catbirds in Michigan, USA

The Condor

Yushi Oguchi, Zachary Pohlen, Robert J. Smith and Jennifer C. Owen

2018 The ability to locate high-quality stopover habitat has fitness implications for migrating landbirds, and alteration of stopover habitats due to human land-use change, including the introduction of nonnative plants, has been identified as a conservation concern. We tested whether the use and selection of shrublands dominated by exotic plants differed from that of native-dominated shrublands. Specifically, we compared capture rates, transfer rates between habitats, within-foraging-range habitat selection, and food items of Swainson's Thrushes (Catharus ustulatus) and Gray Catbirds (Dumetella carolinensis) between exotic- and native-dominated shrublands in Michigan, USA, during fall migration of 2012 and 2013. Capture rates were >20% higher for thrushes and >250% higher for catbirds in native shrubland. Capture–recapture data showed that birds moved from exotic to native shrubland at higher rates than vice versa. For radio-tagged thrushes and catbirds, native shrubland was ∼30% more likely to be used than expected by land cover at the within-foraging-range scale. Thrushes, but not catbirds, avoided exotic shrubs within their foraging ranges. Native Lindera benzoin fruit was >50% more likely to be found in fecal samples from both bird species in native-dominated shrubland than in exotic-dominated shrubland, and was the predominant food item in the former habitat type. Collectively, our results suggest that fall migrating Swainson's Thrushes and Gray Catbirds select, and hence occur at higher densities in, predominantly native shrublands rather than exotic-dominated shrublands. One mechanism for this pattern may be their preference for certain native fruits, such as L. benzoin. Our results suggest that native shrubland may be an especially important stopover habitat for frugivorous birds during fall migration.

Fruits and migrant health: Consequences of stopping over in exotic- vs. native-dominated shrublands on immune and antioxidant status of Swainson's Thrushes and Gray Catbirds

The Condor

Yushi Oguchi Robert J. Smith and Jennifer C. Owen

2017 Migration is a physiologically demanding activity. Recent studies suggest that migrating birds can improve their immune and antioxidant status during stopover, implying that variation in stopover habitat can affect migrants' health. We studied 2 species that are strongly frugivorous during fall migration, Swainson's Thrushes (Catharus ustulatus) and Gray Catbirds (Dumetella carolinensis). We asked whether birds that used shrubland dominated by exotic plants experienced differences in mass change, immune function, and antioxidant status relative to conspecifics in native-dominated shrubland during fall stopover in Michigan, USA, in 2012–2013. We found no habitat-related differences in any of the measured health parameters for Swainson's Thrushes. However, Gray Catbirds using native-dominated shrubland retained mass while those in exotic-dominated shrubland lost mass in 2013. Gray Catbirds in exotic-dominated habitat that year also had poorer immune status (elevated granulocyte:lymphocyte ratio and reduced hemagglutination and haptoglobin) and had lower plasma total carotenoids (immunostimulatory antioxidants) relative to conspecifics in native-dominated shrubland. While these findings were not replicated in 2012, circulating antioxidant capacity was lower in both years in Gray Catbirds captured in exotic habitat. Habitat-specific estimates of dietary energy, carotenoid, and antioxidant content per unit mass of fruit were similar between habitat types for Swainson's Thrushes. For Gray Catbirds, however, the fruit diet was lower in carotenoids and antioxidant capacity, but not in energy, in exotic habitat. Our results provide evidence that differential use of stopover habitats may affect the immune and antioxidant status of migrating landbirds. Furthermore, our results suggest that habitat may affect health status based on the complex relationships among quality and abundance of food, food preferences, and refueling performance, which vary among species. We suggest that future studies measure immune and antioxidant metrics in addition to refueling performance to better understand the effects of stopover habitat use on landbird migrant health. This information may improve assessment of habitat quality for migrants.

Seasonal variation in CREB expression in the hippocampal formation of first-year migratory songbirds: Implications for the role of memory during migration

The Auk

Zoltán Németh, Yuan Luo, Jennifer C Owen, Frank R Moore

2016 Information is key to successful migration. Yet, how much information is learned and stored over the course of migration relative to other phases of the annual cycle is still unknown. We assessed seasonal variation in long-term memory formation indirectly by measuring the expression of cAMP response element binding protein (CREB) in hippocampal samples collected from migratory songbirds, Veery (Catharus fuscescens) and Wood Thrush (Hylocichla mustelina) at different life-history events (fall stopover, spring stopover, breeding season) during their first year of life. Consistent with our prediction, CREB expression was low during autumn (first) migration relative to levels in conspecifics during the first breeding season. These results suggest that young migratory birds may store relatively little spatial information during migration, particularly until they reach their wintering area and their global navigational map is more fully developed.