Ryan Norris

• B.E.S., M.Sc., Ph.D.
• Professor (Associate) at University of Guelph

Migratory animals present a unique challenge for understanding the consequences of habitat loss on population dynamics because individuals are typically distributed over a series of interconnected breeding and non-breeding sites (termed migratory network). Using replicated breeding and non-breeding populations of Drosophila melanogaster and a mathe...

Addressing population declines of migratory insects requires linking populations across different portions of the annual cycle and understanding the effects of variation in weather and climate on productivity, recruitment, and patterns of long-distance movement. We used stable H and C isotopes and geospatial modeling to estimate the natal origin of...

Most animal populations have distinct breeding and non-breeding periods, yet the implications of seasonality on population dynamics are not well understood. Here, we introduce an experimental model system to study the population dynamics of two important consequences of seasonality: sequential density dependence and carry-over effects (COEs). Using...

Understanding the factors that limit and regulate wildlife populations requires insight into demographic and environmental processes acting throughout the annual cycle. Here, we combine multi-year tracking data of individual birds with a 26-year demographic study of a migratory songbird to evaluate the relative effects of density and weather at the...

Identifying the factors driving juvenile recruitment is crucial for predicting the response of populations to environmental change. Importantly, how early life conditions carry over to influence recruitment may be highly dependent on the context in which they occur. For example, the effects of challenging early life conditions may be more pronounce...

For the small number of temperate and boreal species that cache perishable food, previous research suggests that increasing freeze-thaw events can have a negative impact on fitness by degrading the quality of cached food. However, there is no experimental evidence that directly links freeze-thaw events to cache quality. To examine how the timing, f...

Identifying the drivers of population declines in migratory species requires an understanding of how individuals are distributed between periods of the annual cycle. We built post- (fall) and pre-breeding (spring) migratory networks for the blackpoll warbler (Setophaga striata), a Neotropical-Nearctic songbird, using tracking data from 47 light-lev...

The evolution of mating systems reflects a balance of the often-conflicting interests of males and females. Polygyny, a mating system in which males have multiple mates, presents a fitness benefit to males, but the consequences for females are less clear. Females with polygynous social mates may suffer reduced fitness, especially secondary females...

The size and shape of an animal’s breeding territory are dynamic features influenced by multiple intrinsic and extrinsic factors and can have important implications for survival and reproduction. Quantitative studies of variation in these territory features can generate deeper insights into animal ecology and behavior. We explored the effect of age...

Accurately determining the diet of wild animals can be challenging if food items are small, visible only briefly, or rendered visually unidentifiable in the digestive system. In some food caching species, an additional challenge is determining whether consumed diet items have been previously stored or are fresh. The Canada jay (Perisoreus canadensi...

Domestic cats ( Felis catus ) play a dual role in society as both companion animals and predators. When provided with unsupervised outdoor access, cats can negatively impact native wildlife and create public health and animal welfare challenges. The effective implementation of management strategies, such as buffer zones or curfews, requires an unde...

For most birds that exhibit delayed dispersal (remaining on the natal territory rather than dispersing to seek a breeding opportunity), siblings appear free to stay or leave the natal area. However, in rare cases, delaying dispersal is determined via conflict among siblings, with the dominant individual remaining on the natal territory. We used rad...

Male songbirds of many species sing local song dialects that are restricted to defined geographical areas. In most tests of responses to local versus foreign dialects, males respond more aggressively to songs from their own dialect, presumably because local males represent more of a threat to their success. We asked how hearing foreign songs during...

Our understanding of avian incubation behaviour is primarily derived from species that nest in the temperate conditions of spring and summer. This leaves uncertainties about strategies employed by a relatively small number of species adapted to breed under sub-zero, winter-like conditions. We used in-nest temperature loggers (iButtons) to monitor i...

Effective protection of threatened species living in highly urbanized landscapes requires detailed information on their population distribution. For species that are difficult to detect, species distribution models (SDMs) can be valuable tools for predicting their occurrence. We created an SDM to predict breeding pond locations of the endangered Je...

Understanding the environmental drivers of species’ dispersal and migration patterns is needed to accurately predict climate change impacts on populations. For pond-breeding amphibians, adult movements associated with the breeding period are well studied but major gaps exist in our knowledge of the drivers of adult and juvenile non-breeding movemen...

Nearly all wild populations live in seasonal environments in which they experience regular fluctuations in environmental conditions that drive population dynamics. Recent empirical evidence from experimental populations of Drosophila suggests that demographic signals inherent in the counts of seasonal populations, including reproduction and surviva...

While delaying natal dispersal can provide short-term benefits for juveniles, lifetime fitness consequences are rarely assessed. Furthermore, competition for limited positions on a natal territory could impose an indirect fitness cost on the winner if the outcome has negative effects on its siblings. We use radio-tracking and 58 years of nesting da...

Effective conservation of migratory species relies on protection throughout their annual cycle ¹ , something that has not been assessed globally for migratory insects. Here, we develop seasonal ecological niche models for 405 migratory butterfly species globally to assess whether they are adequately covered by protected areas (PAs) across their ful...

Effective conservation of migratory species relies on protection throughout their annual cycle, something that has not been assessed globally for migratory insects. Here, we develop seasonal ecological niche models for 405 migratory butterfly species globally to assess whether they are adequately covered by protected areas (PAs) across their full a...

Anthropogenic activities are exposing insects to abnormal levels of toxic metals, with unknown implications for migratory insects. Simultaneously, metals and metal isotopes have become promising tools for the geolocation of migratory insects. Furthering our understanding of metal cycling in insect tissues is essential, both for the development of m...

Cumulative cultural evolution, the accumulation of sequential changes within a single socially learned behaviour that results in improved function, is prominent in humans and has been documented in experimental studies of captive animals and managed wild populations. Here, we provide evidence that cumulative cultural evolution has occurred in the l...

For many avian species, spatial migration patterns remain largely undescribed, especially across hemispheric extents. Recent advancements in tracking technologies and high‐resolution species distribution models (i.e., eBird Status and Trends products) provide new insights into migratory bird movements and offer a promising opportunity for integrati...

We describe 24 microsatellite loci for an at-risk North American butterfly, the Mottled Duskywing (Erynnis martialis). Forty-one perfect tetra and di-nucleotide loci were originally identified using Illumina sequencing and were refined to 24 variable and cleanly amplifiable loci, which we attempted to characterized in 34 individuals from a single p...

We describe 24 microsatellite loci for an at-risk North American butterfly, the Mottled Duskywing ( Erynnis martialis ). Forty-one perfect tetra and di-nucleotide loci were originally identified using Illumina sequencing and were refined to 24 variable and cleanly amplifiable loci, which we attempted to characterized in 34 individuals from a single...

Social communication often involves vocal learning, whereby young animals learn their vocalizations early in life by imitating the sounds of adults. In animals that learn their vocalizations, it is common to find patterns of geographical variation known as ‘vocal dialects’, acoustic features shared within a cluster of animals that differ from the v...

Addendum to Henault, J., Norris, D.R., Linton, J.E., and Westwood, R. 2022. Adult oviposition, larval host plants and shelter use of the endangered Mottled duskywing (Erynnis martialis) in Canada. The Journal of the Lepidopterists’ Society, 76: 43-55. https://doi.org/10.18473/lepi.76i1.a6.

Many breeding birds produce conspicuous sounds, providing tremendous opportunities to study free-living birds through acoustic recordings. Traditional methods for studying population size and demographic features depend on labor-intensive field research. Passive acoustic monitoring provides an alternative method for quantifying population size and...

Global declines in pollinator populations are an ongoing concern from biodiversity and food security viewpoints. A growing conservation initiative in agricultural landscapes is the establishment of wildflowers on marginal lands to provide floral resources and habitat for pollinators. However, the effectiveness of such conservation and restoration e...

Context Domestic cats (Felis catus) hold an important place in human society but can negatively impact ecosystems when roaming freely outdoors. Aims Specific research goals included identifying factors associated with cat abundance over the year. Methods We deployed trail cameras in Wellington County, Ontario, Canada to estimate what habitat char...

Space-based tracking technology using low-cost miniature tags is now delivering data on fine-scale animal movement at near-global scale. Linked with remotely sensed environmental data, this offers a biological lens on habitat integrity and connectivity for conservation and human health; a global network of animal sentinels of environmental change.

Habitat preferences in animals are often examined during the breeding period when individuals are easier to observe. However, habitat use may change once young become independent and if resource availability shifts with seasonality. While Canada Jays (Perisoreus canadensis (Linnaeus, 1766)) in Algonquin Provincial Park, Ontario, Canada, have been s...

Conservation practitioners widely recognize the importance of making decisions based on the best available evidence. However, the effectiveness of evidence use in conservation planning is rarely assessed, which limits opportunities to improve evidence‐based practice. We devised a mixed methodology for empirically evaluating use of evidence that app...

The Mottled duskywing (Erynnis martialis) butterfly is endangered, living in pine forests and oak barrens in Canada and the eastern United States of America. While host plants and larval behaviour is documented in Mottled duskywing’s eastern range, these life components are poorly known in Manitoba. We observed adult behaviour, host plant species u...

For many species, breeding performance increases through early adulthood followed by declines later in life. Although patterns of age-specific decline have been shown to vary between individuals, the factors that lead to this individual variation in the intensity of reproductive senescence are yet to be fully understood. We investigated whether ear...

Tissue samples are frequently collected to study various aspects of avian biology, but in many cases these samples are not used in their entirety and are stored by the collector. The already collected samples provide a largely overlooked opportunity because they can be used by different researchers in different biological fields. Broad reuse of sam...

How animals choose habitats during periods of inactivity, such as roosting or resting, is an often overlooked aspect of habitat preference that can differ significantly from how habitats are selected during active periods. Eastern Whip-poor-wills (Antrostomus vociferus) are migratory nocturnal aerial insectivores that breed throughout eastern North...

Breeding dispersal can influence fitness as well as the dynamics and genetic architecture of populations, but the patterns and causes of dispersal in most species are still poorly understood. Here, we used 55 years of re-sighting and breeding data from 530 individually marked adult Canada jays at the southern edge of their range in Algonquin Provin...

Phenotypic plasticity allows organisms to adjust the timing of life‐history events in response to environmental and demographic conditions. Shifts by individuals in the timing of breeding with respect to variation in age and temperature are well documented in nature, and these changes are known to scale to affect population dynamics. However, relat...

Nonstop endurance flights are a defining characteristic of many long-distance migratory birds, but subsequent recovery phases are not typically distinguished from fueling phases (collectively “stopovers”), despite endurance flights inducing marked physiological changes including flight muscle atrophy and gastrointestinal tract reductions. Here, we...

The biotic and abiotic factors responsible for determining ranges of most species are poorly understood. The Canada Jay (Perisoreus canadensis (Linnaeus, 1766)) relies on perishable cached food for over-winter survival and late-winter breeding and the persistence of cached food could be a driver of range limits. We confirmed that the Canada Jay’s l...

Abstract Whether an individual disperses or remains site‐faithful between breeding seasons can have important impacts on individual fitness and population dynamics. While several studies have identified factors influencing the probability of breeding dispersal, the consequences of dispersal are much less certain, particularly over an individual’s l...

Strontium isotope ratios (⁸⁷Sr/⁸⁶Sr) have shown promise for tracing the geographic origin of animal tissues because they have high‐resolution and show discrete spatial patterns independent and complementary to those of light isotopes. In this study, we provide a complete quantitative framework to apply ⁸⁷Sr/⁸⁶Sr for tracking migratory animals using...

Nongovernmental organizations contribute to the securement and management of protected areas, but it is not well known how their lands compare to government protected areas or the effectiveness of different land acquisition strategies. Using data from the International Union for Conservation of Nature and BirdLife International, we estimated total...

Synopsis Individuals undergo profound changes throughout their early life as they grow and transition between life-history stages. As a result, the conditions that individuals experience during development can have both immediate and lasting effects on their physiology, behavior, and, ultimately, fitness. In a population of Canada jays in Algonquin...

Vocal learning is a biologically rare adaptation that underpins both human language and the songs of songbirds. The adaptive value of vocal learning in birds is still poorly understood, but a growing body of literature suggests that vocal learning allows songbirds to gain a fitness advantage by adopting songs that are structurally similar to the so...

Eastern North American migratory monarch butterflies (Danaus plexippus) have faced sharp declines over the past two decades. Captive rearing of monarch butterflies is a popular and widely used approach for both public education and conservation. However, recent evidence suggests that captive-reared monarchs may lose their capacity to orient southwa...

Neonicotinoid insecticides are the most widely used class of insecticides in the world and can have both lethal and sub‐lethal effects on non‐target organisms in agricultural areas. Monarch butterflies Danaus plexippus have experienced dramatic declines in recent decades and, given that a large proportion of milkweed on the landscape grows in agric...

Recent studies have demonstrated that generic statistical signals derived from time series of population abundance and fitness‐related traits of individuals can provide reliable indicators of impending shifts in population dynamics. However, how the seasonal timing of environmental stressors influences these early warning indicators is not well und...

Neonicotinoid insecticides are used to reduce crop damage caused by insect pests, but sublethal levels could affect development and reproduction in nontarget insects, such as monarch butterflies ( Danaus plexippus ) (Lepidoptera: Nymphalidae). To investigate the impact of field-realistic concentrations of the neonicotinoid clothianidin on monarch b...

Diet quality during development can impact growth, physiology, behaviour, and survival. The Canada jay is a resident boreal passerine that caches a wide variety of perishable food items in late summer and autumn for its over‐winter survival and late‐winter reproduction. A previous experiment found evidence that food supplementation of Canada jay pa...

Understanding how events throughout the annual cycle are linked is important for predicting variation in individual fitness, but whether and how carry‐over effects scale up to influence population dynamics is poorly understood. Using 38 years of demographic data from Algonquin Provincial Park, Ontario, and a full annual cycle integrated population...

Migratory insects use a variety of innate mechanisms to determine their orientation and maintain correct bearing. For long-distance migrants, like the monarch butterfly (Danaus plexippus), these journeys could be affected by exposure to environmental contaminants. Neonicotinoids are synthetic insecticides that work by affecting the nervous system o...

Although density regulates the abundance of most wild animal populations by influencing vital rates, such as fecundity and survival, the mechanisms responsible for generating negative density dependence are unclear for many species. Site dependence occurs when there is preferential filling of high‐quality territories, which results in higher per ca...

Understanding population demography and dispersal of species at risk is integral for evaluating population viability, identifying causes of decline, and assessing the effectiveness of recovery actions. In pond-breeding amphibians, juvenile survival and dispersal are key components linked to population and metapopulation stability but little is know...

Carry-over effects occur when past experience influences current individual performance. Although variation in conspecific density in one season has been shown to carry over to influence dynamics in the following season, the proximate ecological mechanisms driving these effects are unknown. One hypothesis is that high density decreases food availab...

Survival probability is fundamental for understanding population dynamics. Methods for estimating survival probability from field data typically require marking individuals, but marking methods are not possible for arthropod species that molt their exoskeleton between life stages. We developed a novel Bayesian state‐space model to estimate arthropo...

Migration theory has largely overlooked the role of overwintering grounds and yet many migratory animals spend most of the annual cycle there. High winter site familiarity could confer considerable advantages on animals preparing for subsequent migration phases, enabling them to maximize migration speed and minimise the use of unknown stopover site...

Various multiple-disciplinary terms and concepts (although most commonly “interdisciplinarity,” which is used herein) are used to frame education, scholarship, research, and interactions within and outside academia. In principle, the premise of interdisciplinarity may appear to have many strengths; yet, the extent to which interdisciplinarity is em...

The past several decades have ushered in a golden age in the study of migration biology, leading to a wealth of descriptive articles that characterize various aspects of migration and its implications for individuals, populations, and ecosystems. However, relatively few studies have adopted an experimental approach to the study of migration, and fe...

Habitat protection is a key component of endangered species conservation, but critical habitat designations are often based on limited data or habitat use during only a portion of a species’ life cycle. Protected habitat around breeding pools for the endangered Jefferson Salamander (Ambystoma jeffersonianum (Green, 1827)) and their unisexual depend...

Eastern North American migratory monarch butterflies (Danaus plexippus) have faced sharp declines over the last two decades. Although captive rearing has been used as an important tool for engaging the public and supplementing conservation efforts, a recent study that tested monarchs in a flight simulator suggested that captive-reared monarchs lose...

Grassland birds are in decline worldwide and one hypothesis for this decline is habitat loss and degradation through agricultural intensification. The purpose of this study is to investigate the impacts of agriculture on a declining grassland bird, the Savannah Sparrow (Passerculus sandwichensis). Over two breeding seasons nests were located and mo...

The vocalizations of birds are dynamic traits that often vary in output with time of day and time of year. By quantifying patterns of diel and seasonal variation in vocal output, we can gain insight into the ecology and evolution of birds and the function of their vocalizations. In this investigation, we quantified diel and seasonal variation in so...

Food availability early in life can play a vital role in an individual's development and success, but experimental evidence for the direct effects of food on body condition, physiology, and survival of young animals in the wild is still relatively scarce. Food‐caching Canada Jays (Perisoreus canadensis) begin breeding in the late winter and, theref...

For declining wild populations, a critical aspect of effective conservation is understanding when and where the causes of decline occur. The primary drivers of decline in migratory and seasonal populations can often be attributed to a specific period of the year. However, generic, broadly applicable indicators of these season‐specific drivers of po...

Aggressive behavior is common in many species and is often adaptive because it enables individuals to gain access to limited resources. However, aggression is also highly plastic and the degree of plasticity could be influenced by factors such as resource limitation and the social environment. In this study, we examined how the effects of social ex...

During migration, animals may experience high rates of mortality, but costs of migration could also be manifested through non-lethal carry-over effects that influence individual success in subsequent periods of the annual cycle. Using tracking data collected from light-level geolocators, we estimated total spring migration distance (from the last w...

Animals often live within close proximity of multiple conspecific individuals, allowing them to eavesdrop on other animals' signalling interactions to guide their own social behaviours. For a young animal that is learning to vocalize, eavesdropping on vocal interactions between adults may provide a rich source of information: young animals might pr...

Abstract Migratory behaviors such as the timing and duration of migration are genetically inherited and can be under strong natural selection, yet we still know very little about the specific genes or molecular pathways that control these behaviors. Studies in candidate genes Clock and Adcyap1 have revealed that both of these loci can be significan...

Insects represent the most diverse and functionally important group of flying migratory animals around the globe, yet their small size makes tracking even large migratory species challenging. We attached miniaturized radio transmitters (less than 300 mg) to monarch butterflies ( Danaus plexippus) and common green darner dragonflies ( Anax junius) a...

Monarch butterflies (Danaus plexippus, Linnaeus, 1758) are comprised of two migratory populations separated by the Rocky Mountains and are renowned for their long-distance movements among the United States, Canada, and Mexico. Both populations have declined over several decades across North America prompting all three countries to evaluate conserva...

There have been an increasing number of observations of itinerancy in migratory songbirds, where individuals move among 2 or more widely separated areas during the “stationary” nonbreeding season. Knowledge of such movements and an understanding of what drives them are important for predicting how migratory populations will respond to environmental...

The eastern North American migratory population of monarch butterflies (Danaus plexippus) has declined precipitously due, in part, to the widespread decline of its obligate host plant, milkweed (Asclepias spp.). Linear right-of-ways (e.g. roadsides, power line corridors) are believed to be a significant source of milkweed and represent a valuable t...

Evidence suggests that range-edge populations are highly vulnerable to the impacts of climate change, but few studies have examined the specific mechanisms that are driving observed declines. Species that store perishable food for extended periods of time may be particularly susceptible to environmental change because shifts in climatic conditions...

The migratory monarch butterflies (Danaus plexippus) of eastern North America have undergone large-scale declines, which may be attributable to a variety of underlying causes. The uncertainty about the primary cause of declines and whether individual threats are likely to increase in the future presents challenges for developing effective conservat...

Currently, the deployment of tracking devices is one of the most frequently used approaches to study movement ecology of birds. Recent miniaturization of light‐level geolocators enabled studying small bird species whose migratory patterns were widely unknown. However, geolocators may reduce vital rates in tagged birds and may bias obtained movement...

Latitudinal differences in timing of breeding are well documented but how such differences carry over to influence timing of events in the annual cycle of migratory birds is not well understood. We examined geographical variation in timing of events throughout the year using light-level geolocator tracking data from 133 migratory tree swallows (Tac...