CHICAGO—July 13, 2026—The American Ornithological Society (AOS) today announced our 2026 Kessel Fellowships for Ornithological Research for early-career researchers. The AOS Kessel Fellowship funding supports the full range of ornithological research by early-career scientists currently published in peer-reviewed journals, such as avian biology, ecology, behavior, conservation, genetics, and interdisciplinary work. One arctic research 2026 Kessel Fellowship of $30,000 was awarded to Dr. Audrey Le Pogam ; and six individual $15,000 fellowships were awarded to Drs. Carrie Ann Adams , David Diez-Méndez , Jennifer L. Houtz , Abby Kimmitt , Amy Yanagitsuru , and Laura E. Nuñez-Rosas to support their ornithological research projects.
“Each year the task of selecting Kessel Fellows gets more difficult, as the pool of excellent applicants grows,“ says Kessel Fellowship Committee Chair Carrie Branch. “This year we were able to fund more projects (a total of seven) than we have in the history of the program and we’re really proud of that. Work from researchers at primarily undergraduate institutions (those without Ph.D. programs) really shined this year, as did researchers focused on understanding how anthropogenic activity affects avian ecology and behavior. Congratulations to this year’s Kessel Fellows!”
“The 2026 Kessel Fellows are at the forefront of ornithological research; their work addresses a range of questions that will advance our understanding of birds and potentially inform future conservation efforts,” states AOS President Sara Morris. “We are so fortunate to be in a financial position to provide Kessel fellowships, and I am so pleased we have been able to expand the program. I don’t envy the committee the difficult task of choosing among the strong applications for this program.”
Congratulations to these grantees! Read on for more information about the researchers and the projects being funded by this year’s Kessel Fellowships for Ornithological Research.
Early Career Researcher, Université du Québec à Rimouski, Laboratoire d'écophysiologie aviaire
Audrey Le Pogam, Ph.D., is an early-career researcher at the Université du Québec à Rimouski (UQAR) whose work focuses on avian ecophysiology and the impacts of rapid Arctic warming on cold-adapted northern species. She is involved in training early-career scientists and ornithologists, co-developed an intensive course in energetic ecology in Uruguay, and currently teaches Conservation Physiology at UQAR. Her doctoral research examined phenotypic flexibility in Plectrophenax nivalis (Snow Bunting), an Arctic-breeding migratory passerine, revealing remarkable physiological adaptations to extreme cold and providing insight into how Arctic specialists respond to environmental variation and climate change.
In 2015, she co-founded the world’s northernmost wildlife research laboratory at CFS Alert, Nunavut , where she has conducted research for over a decade and now coordinates projects on Arctic wildlife responses to environmental change. She has presented at more than 50 national and international conferences and published more than 15 peer-reviewed articles.
Originally from France, Le Pogam completed her Master’s in ecology and ethology at Université Jean Monnet before moving to Canada in 2014 to pursue a Ph.D. in avian ecophysiology at UQAR under the supervision of François Vézina, Ph.D., and Oliver Love, Ph.D.
Follow Dr. Le Pogam’s research: ORCID ; RESEARCHGATE
Project title: “Thermal constraints on reproduction in a cold-adapted songbird across High and Low Arctic Canada”
Abstract: Arctic ecosystems are warming at more than twice the global rate, yet the physiological and behavioral consequences of heat exposure for Arctic wildlife remain poorly understood. This gap is critical because most predictions of species vulnerability rely on simplified thermal limits that do not account for behavior, microclimate, or reproductive demands.
This project investigates how heat stress constrains reproductive performance in a cold-adapted Arctic songbird, the Snow Bunting (Plectrophenax nivalis, 30–50g), a species that has declined by ~80% in Canada since the 1970s. Despite its exceptional adaptation to extreme cold, Snow Buntings have limited heat tolerance and may overheat at moderate temperatures during the breeding season. This is particularly relevant because adults must sustain high provisioning rates during the warmest period of the year, under nearly continuous solar exposure in Low Arctic and continuous 24-hour daylight in High Arctic, combining heat generated from flight to air temperature and solar radiation, when thermal conditions can exceed their capacity for heat dissipation.
We combine fine-scale physiological measurements (body temperature via RFID-based loggers), behavioral monitoring (nest visitation rates), microclimate characterization using micro-weather stations and calibrated 3D-printed bird models to estimate operative temperatures experienced by breeding adults. These data are integrated with reproductive metrics (nestling growth, clutch size, and fledging success) in High Arctic (Alert) and Low Arctic (Iqaluit) populations.
This design allows us to directly test how thermal environments shape parental effort and reproductive output, and whether repeated or prolonged heat exposure reduces provisioning capacity and offspring performance. We further identify critical temperature thresholds beyond which reproductive success declines.
By linking physiology, behavior, and environmental conditions within a mechanistic framework, this study provides the first empirical test of how heat stress affects reproduction in a wild Arctic passerine. While Snow Buntings are more accessible than many Arctic birds, the findings will provide a transferable framework for understanding vulnerability across Arctic birds and generate actionable knowledge for wildlife managers and northern communities under future warming scenarios.
Post-doctoral Fellow, Purdue University, Carleton University
Carrie Ann Adams, Ph.D., is a postdoctoral fellow at Carleton University, where she was awarded a Liber Ero fellowship and a National Science and Research Council of Canada Fellowship. She is also a postdoctoral fellow at Purdue University in the United States, where she is a co-investigator on a NASA Biodiversity and Conservation award. She is currently updating and extending radar-based maps of bird migration into Canada, developing a multi-spectral map of artificial light at night, and studying how the blue content of light affects migratory bird response. She is passionate about reducing light pollution in North America and beyond for the benefit of migratory birds, humans, and other wildlife.
Adams received her B.Sc. and M.Sc. degrees from Stanford University in Earth Systems Science in 2012 and 2014. She worked at Teton Raptor Center for three years rehabilitating raptors and researching Strix nebulosa (Great Gray Owl). She received her Ph.D. in Biological Sciences from the University of Alberta in 2023, where she studied the effects of light pollution on birds. During her Ph.D. program, she was awarded the McAfee Estate Scholarship in Zoology, the Bill Shostak Wildlife Award, and Alberta Conservation Association Grant in Biodiversity to research the effects of artificial light on nightjars in Western Canada. She completed her first post-doctoral fellowship at Colorado State University to study bird migration phenology in the U.S. using weather surveillance radar.
Follow Dr. Adam’s research: ORCID
Project title: “Protecting nocturnally migrating birds from artificial light: Do blue light and fog increase attraction?”
Abstract: Migratory bird attraction to artificial light at night is well documented, especially on foggy nights, with deadly consequences of collisions with buildings or sublethal effects of delayed migrations. However, some studies show that birds avoid artificial lights during migration, and their responses can depend on weather and light characteristics. Birds are more sensitive to blue than humans are and many LEDs have a higher blue content than the older lamp types, so the global conversion to blue-rich LEDs may increase their attraction or deterrence. At a remote ranch in Texas, we are using a portable BirdScan MR1 radar and three lights with varying blue content to test whether (a) migrating birds respond more to bluer lights and (b) whether the degree of attraction or deterrence depends on the density of fog or mist. The radar measures the number of birds within 500 meters of the light source and their flight heights. We will determine if there are more/fewer birds or lower/higher flight heights when the lights are turned on, which would indicate attraction/deterrence, respectively. We will also measure the aerosolized water content of the air (i.e., fog or mist) to determine how it alters bird response to light. Because birds are likely to encounter hundreds or thousands of similarly bright light sources on each night that they migrate, both attraction or deterrence can cost them energy that they need to successfully complete their migrations.
Postdoctoral Researcher, Netherlands Institute of Ecology (NIOO-KNAW)
David Diez-Méndez, Ph.D., is a behavioral ecologist with a broad interest in ornithology and evolution. He is currently a postdoctoral researcher at the Netherlands Institute of Ecology (NIOO-KNAW), where he investigates how diet–microbiome interactions influence avian behavior. His research encompasses two main areas: one investigating female incubation behavior, responses to environmental change, and the consequences for offspring development; and another exploring how host–microbiome interactions shape avian ecology, physiology, and behavior. He primarily uses Parus major (Great Tit) as a model system in both wild and captive settings.
Diez-Méndez grew up in Spain, where he completed a degree in Biology at the University of Salamanca and a master's degree in Biodiversity and Evolution at the University of Valencia. It was during this period that he developed a lasting interest in ornithology. After two years in field and technical assistant positions on avian-related projects across Europe, he returned to Spain to undertake a Ph.D. fellowship at the National Museum of Natural Sciences in Madrid and the University of Valencia. His doctoral research focused on how environmental factors shape female incubation behavior in P. major . It was during his first postdoctoral position in Czechia, where he developed a growing interest in microbial ecology while investigating gut microbial colonization during early-life development in P. major .
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Project title: “MICROCLOCKS: Gut microbiome facilitates adaptation to Arctic light-dark cycles”
Abstract: Northward shifts in species distributions in recent decades are a consequence of climate change. Previously uninhabitable or unsuitable regions now serve as fitting breeding areas for avian species, such as those colonizing the Arctic Circle. A clear example is the recent arrival of Great Tits (Parus major) in Tromsø, Norway. However, regardless of how favorable Arctic environments may become, extreme light-dark (L-D) cycles are unavoidable, impacting individual behavior and physiology.
Our understanding of how avian species succeed in colonizing these habitats is very limited, with evidence indicating opportunistic behavior under dampened daily rhythms in the absence of light cues during summer and winter. In Tromsø, only part of the great tit population shows dampened daily rhythms, while others maintain rhythmic activities. To identify the mechanism underlying these phenomena, I hypothesize that differential gut microbiome (GM) gene expression may influence the division of these new Arctic inhabitants into the two observed behavioral groups.
It is known that GM daily oscillations follow host daily rhythms. In the absence of an L-D cycle and with a dampened host circadian system, GM rhythmicity can be maintained by periods of food intake and deprivation, as observed in laboratory animal models. In an Arctic context, differences in feeding behavior may translate into different rhythms in GM gene expression, affecting metabolite synthesis linked to host circadian rhythms (e.g., melatonin, short-chain fatty acids). The GM is expected to function as an additional internal clock regulated by non-photic cues.
I will classify Arctic tits based on behavioral phenotypes (rhythmic or arrhythmic), determine whether GM gene expression follows these rhythms and how it changes under different L-D cycles (equinox and solstice). Lastly, I will test whether food ingestion acts as a non-photic cue for GM circadian rhythms under experimental conditions.
This project is a stepping stone to unravel the key role of the GM in Arctic colonization. Understanding short-term eco-evolutionary dynamics between the GM and their wild hosts in recently colonized environments will help forecast key population poleward expansions in other avian groups.
Assistant Professor of Biology, Allegheny College
Jennifer Houtz, Ph.D., is an assistant professor of biology at Allegheny College, a primarily undergraduate institution in Pennsylvania. Her research at Allegheny College focuses on physiological mediators of stress resilience in cavity-nesting birds. She studies how interactions between hormones and the gut microbiome influence avian physiology, behavior, and fitness. Dr. Houtz also maintains an active science outreach program including live-streaming bird nests to elementary school classrooms and providing free nest boxes to families in Meadville, Penn.
She received her Ph.D. in Ecology and Evolutionary Biology from Cornell University, where she studied the gut microbiome as a mediator of phenotypic plasticity in Tachycineta bicolor (Tree Swallows). Dr. Houtz received her B.S. in Animal Behavior from Millersville University. She served as one of the co-chairs of the AOS Students Affairs Committee (2020–2022). She currently serves on the Meeting Coordination Committee (2020–present), Professional Ethics Committee (2021–present) and as co-chair of the Early Professionals Committee (2024–present). She has mentored more than 50 undergraduate students in ornithological research.
Houtz is a past recipient of an AOS Student Research Award (2019), AOS Student Travel Grant (2019), and the Robert Lochmiller Early Professional Award from the Division of Ecoimmunology and Disease Ecology of the Society of Integrative and Comparative Biology (2025).
Follow Dr. Houtz’s research: WEEBLY
Project title: “Avian gut microbiomes and host immune phenotypes across a thermal geographic gradient”
Abstract: Disease arises from a complex interaction between genetic and environmental factors that disrupt host homeostasis. As climate change becomes more pervasive, temperature is a primary environmental factor of interest that may impact organismal immune performance. Dysregulation of the gut microbiome in early life may be a mechanism by which rising global temperatures will impact disease susceptibility and fitness in wild populations, as gut bacteria guide host immune development and temperature shapes bacterial composition in ecosystems globally. The capacity of the gut bacterial community to change its diversity or composition in response to ambient temperature is likely an essential mediator that facilitates host adaptation to local thermal environment and subsequent immune function. Here, I aim to understand how thermally-induced bacterial shifts may impact host immunity and fitness in Eastern Bluebird ( Sialia sialis ) nestlings which are commonly parasitized by blowflies ( Protocalliphora sialia ). Through a collaborative project led by Sarah Knutie, Ph.D. (University of Connecticut), we collected over 500 fecal samples from Eastern Bluebird nestlings across eight different populations along a latitudinal gradient that were experimentally reared at different temperatures. I hypothesize that the gut microbiomes of Eastern Bluebird nestlings are adapted to local thermal environments and mediate host immune responses to ectoparasites (blowflies). I will sequence the bacterial microbiomes of these fecal samples to uncover how the gut microbiome may mediate host-parasite interactions across thermal contexts. These preliminary data will allow me to pursue novel research directions in the field of avian gut microbiomes and provide invaluable training opportunities for undergraduates.
Assistant Professor, Hofstra University
Abby Kimmitt, Ph.D., is currently an assistant professor at Hofstra University in Hempstead, New York. Her research examines the physiological mechanisms underlying the timing of seasonal behaviors and the evolutionary consequences of variation in those behaviors. Specifically, she studies the genomic and hormonal regulation of reproduction and migration in songbirds in order to understand how animals adapt to seasonal environments in the context of climate change. She received her Ph.D. in Ecology, Evolution, and Behavior from Indiana University and her B.S. in Biology from the University of Mary Washington. She is a past winner of an American Ornithological Union (AOU) Student Research Award (2016).
Follow Dr. Kimmitt’s research: ORCID
Project title: “Neuroendocrine and behavioral responses of songbirds to long-term heat waves”
Abstract: An increase in the frequency and severity of extreme weather conditions, such as heat waves, poses challenges for animal thermoregulation, reproduction, and survival. And yet, the endocrine and metabolic mechanisms that allow birds to cope with these challenges remain poorly understood, especially in non-model species. The House Sparrow (Passer domesticus) is one of the most broadly distributed invasive vertebrates across the globe. The adaptability and near-global distribution of House Sparrows demonstrate their usefulness as a study system to investigate physiological mechanisms underlying thermoregulatory and reproductive tradeoffs in response to environmental change. To elucidate physiological and behavioral mechanisms of heat stress thermoregulation, I will simulate a 7-day heat wave for captive male and female House Sparrows in reproductive condition. By studying male and female sparrows, I will explore whether sexes differ in their response to a heat wave, which could have implications for sex differences in reproductive success and overall population persistence. I will ask: 1) How do behavioral responses change over the duration of a long-term heat wave? 2) How do differences in hormonal and chemical signaling relate to exposure to heat stress? And 3) How is gene expression in the preoptic area (POA) of the hypothalamus associated with response to heat waves? Behavior, including panting and wing spreading, will be recorded via video camera for the duration of the treatment. Blood samples will be collected prior to the treatment (day 0) and during the treatment (day 1 and day 7) to measure circulating levels of corticosterone and nitric oxide. Birds will be euthanized on day 7, and the brain will be collected for gene expression analysis. Results from this work will better inform how songbirds are able to acclimate and respond to unpredictable weather challenges associated with climate change and will provide essential data to forecast songbird population persistence.
Adjunct Professor, Wilkes University
Amy Yanagitsuru, Ph.D., works as an adjunct professor in the Biology and Earth Systems Sciences department at Wilkes University. She is conducting research on long-term territorial relationships in ovenbirds and is setting up a nest box network to study monogamy in Megascops asio (Eastern Screech-Owl). She is also applying her dataset interests to a side project on gender differences in the peer-review system.
Yanagitsuru received her bachelor's degree from Bryn Mawr College and completed her Ph.D. at the University of California Davis. Her Ph.D. research involved several seabird projects: ways to use RFID to identify breeding Ashy storm-petrels and the benefits of pair-bonding in Cassin's auklets on the Farallon Islands and a global dataset project on the influence of diet diversity on breeding timing variability across many seabird species. She completed a postdoc at the University of Nevada Reno, where she worked on microbiome differences in urban and rural house wrens and another data project on aspects of city parks that correlate with the presence of urban-avoidant bird species.
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Project title: “Puffin Love: Mechanisms behind the benefits of long-term pair bonding in Atlantic Puffins”
Abstract: Perennial monogamy—colloquially known as "mating for life"—is an extreme form of social monogamy whereby partners maintain their bond over multiple breeding seasons. Although this is a rare breeding strategy in animals, it has representatives in birds, insects, fish, lizards, and is, of course, present in humans. It has been widely demonstrated across both avian and non-avian taxa that pairs who have bred together before have better reproductive success than pairs who are breeding together for the first time, and this effect persists even when the parenting experience of each individual is considered. Although a long-term bond has clear benefits, what experienced pairs are doing differently from newly-formed pairs that leads to improved success is unclear.
In this project, I will use physiological, behavioral, and breeding success data to evaluate several competing hypotheses for why long-term bonds improve reproductive success using Atlantic Puffins ( Fratercula arctica ). Firstly, teamwork and physiological coordination could improve with experience raising offspring together, leading to lower rates of neglect from mismatched alternation of foraging and nest attendance. Alternatively, parents with experience together could specialize in sex-specific parental roles, trusting that their partner will perform the other duties. In this case, females may invest their limited energy in laying a larger egg, restricting the resources they have available to perform chick care and relying on their partner to take on more of the parenting responsibilities. There may also be no differences in behavior or physiology between experienced and inexperienced pairs. In this case, it may be an effect of loyalty to a nest site rather than the partner. Between these three ideas, we can further our understanding of why birds show a mating system that is simultaneously extreme, unusual, and grants a kind of kinship or a source of public sympathy for birds among the public.
Full-time Professor A, Facultad de Estudios Superiores Iztacala, UNAM
Laura E. Nuñez-Rosas, Ph.D., is a full-time professor A at the Facultad de Estudios Superiores Iztacala, UNAM. Her research focuses on ornithology, behavioral ecology, pollination ecology, and conservation biology, with particular emphasis on hummingbirds (Trochilidae). Her work examines hummingbird reproductive ecology, nesting biology, torpor, plant–hummingbird interactions, urban ecology, and climate change impacts on pollinators. She has contributed to collaborations on biodiversity conservation and hummingbird ecology. Nuñez-Rosas has authored and co-authored publications in journals including Behaviour , Journal of Animal Ecology , Perspectives in Ecology and Conservation , and Journal of Urban Ecology .
Nuñez-Rosas earned a B.Sc. in Natural and Agricultural Resources Engineering from the University of Guadalajara, and both her M.Sc. and Ph.D. in Biological Sciences from the Centro Tlaxcala de Biología de la Conducta at the Universidad Autónoma de Tlaxcala. She also completed postdoctoral research at UNAM and the Benemérita Universidad Autónoma de Puebla. Her distinctions include the Hummingbird Monitoring Network and U.S. Forest Service International Program Short-term Scholar Award (2010), the Latin American Caribbean Travel Award for the North American Ornithological Conference (2016), the Partners in Flight International Conference Travel Scholarship (2017), and membership in Mexico’s National System of Researchers (SNI), where she currently holds Level I status (2023–2027).
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Project title: “Torpor during reproduction: the role of nesting microhabitats in hummingbirds”
Abstract: Hummingbirds experience extreme energetic demands during reproduction because females alone are responsible for nest construction, incubation, and chick provisioning. One strategy that may help females cope with these energetic constraints is torpor, a reversible reduction in metabolic activity that lowers nighttime energy expenditure. However, torpor during reproduction may involve trade-offs, as reduced body temperature could affect nest thermal stability and embryo development. Despite growing interest in avian torpor, little is known about how nesting microhabitat influences torpor use in free-living reproductive hummingbirds.
This project will evaluate how nest-site selection and vegetation structure affect torpor use, maternal behavior, and reproductive success in hummingbirds across environmental gradients in Mexico. Fieldwork will be conducted in tropical dry forest, cloud forest, oak forest, and pine-oak forest ecosystems using multiple hummingbird species as study models. Nests will be monitored throughout the breeding season to document reproductive stage, nest fate, and maternal investment. Nest microhabitat characteristics, including canopy cover, vegetation structure, and habitat complexity, will be quantified using hemispherical photography and UAV imagery.
To assess torpor use, nocturnal body surface temperature of reproductive females will be recorded non-invasively using infrared thermography and related to local environmental conditions measured by dataloggers. The project will test whether thermally buffered microhabitats reduce torpor use and improve reproductive success compared to colder or more exposed nesting sites.
By integrating physiology, reproductive ecology, and habitat structure, this study will provide one of the first field-based evaluations of reproductive torpor in hummingbirds and contribute to understanding how small birds reproduce under strong energetic and environmental constraints.
The American Ornithological Society (AOS) is an international society dedicated to connecting ornithologists, science, and bird conservation by supporting science that advances the understanding and conservation of birds; promoting broad access to ornithological science; supporting ornithologists throughout their career paths; and fostering a welcoming, diverse, supportive, and dynamic ornithological community. The AOS publishes two top-ranked international scientific journals, Ornithology and Ornithological Applications , and hosts an annual conference that attracts ornithologists from across the globe. Its robust grants program supports student and early-career professional research initiatives. The society’s check-lists serve as the accepted authorities for scientific nomenclature and English common names of birds in the Americas. The AOS is also a partner with The Cornell Lab of Ornithology in the online Birds of the World , a rich database of species accounts of the world’s birds. The AOS is a 501(c)(3) nonprofit organization serving about 3,000 members globally. For more information, see www.americanornithology.org .