Migration Routes Research Articles

Numerical modelling of radionuclide uptake by bluefin tuna along its migration routes in the Mediterranean Sea after a nuclear accident

A numerical model which simulates the adsorption of radionuclides by migrating bluefin tuna in the Mediterranean Sea is described, in order to determine the level of contamination of these fish after a hypothetical nuclear accident and thus be able to assess the possible impact on human consumption. A 4–species foodweb model is incorporated into a Lagrangian model describing physical transport (advection, mixing, radioactive decay and interactions of radionuclides with sediments). Tuna is the last trophic level in the foodweb model and the equation providing the temporal evolution of radionuclide concentration in its flesh is solved along the fish trajectories, which were obtained through electronic tagging of fishes. The model was applied to the western Mediterranean, where several worst–case hypothetical accidents were simulated, both from a coastal nuclear power plant and from a vessel. Resulting 137Cs concentrations in migrating tuna were similar, or slightly higher, than reported background concentrations in these fishes and well below established safety levels. Maximum calculated concentrations in tuna flesh is in the order of 1 Bq/kg (wet weight). This is due to the rapid movement of the fishes, which spend only limited time over the most contaminated spots.

Optimizing the Migratory Environment of Wildebeests in the Maasai Mara Reserve with a New Ecological Corridor and Customized Buffer Zone Model

Conflicts between wildlife and humans are a major ecological issue. During migration, wildlife, especially wildebeest, often encounter significant environmental pressures from human activities. However, relatively few studies have been conducted to provide a concise, quantitative description of wildebeest migration in the Maasai Mara National Reserve (MMNR). In this study, we identified changes in the location of the wildebeest population over time in the Maasai Mara National Reserve. We then used a K-means algorithm (R2 = 0.926) to fit coordinates representing the changes in the location of the wildebeests to enable a quantitative representation of their migration routes. Subsequently, we developed an environmental stress model to assess the changes in environmental stresses faced by wildebeests along their migration routes. We proposed a model of “migratory ecological corridors and customized buffer zones” and determined the response coefficient T_res. We used the response coefficients T_res = 0.06, 0.09, and 0.12 as the critical values to categorize the areas along the routes into weak, medium, and strong response regions. Then, we set the width of the buffer zones on both sides of the routes as 5 km, 7 km, and 9 km, respectively, and evaluated the buffer effect. This type of model achieved a good effect of reducing the environmental pressure by 54.06%. The “Migratory Ecological Corridor and Customized Buffer Zone” model demonstrated a high degree of economic feasibility while showing good practicality in mitigating the environmental conflicts between humans and migratory wildlife. The variability in the environmental pressures across the region indicates that the Nairobi and Nakuru districts may be undergoing a particular stage of urbanization that unleashes potential threats to the migration of wildebeests. Further research is essential to assess the feasibility of larger buffer zones.

A review of climate change impacts on migration patterns of marine vertebrates in Arctic and Subarctic ecosystems

Climate change is impacting marine ecosystems throughout the circumpolar Arctic, altering seasonal habitats and the food bases for fishes, seabirds, and marine mammals. Arctic and Subarctic regions provide resources for resident species and for species that migrate to the north from more southerly regions. Changes in northerly latitudes thus impact endemic as well as non-endemic animals. Herein, we review what is known about climate-driven changes in the migration patterns of Arctic and Subarctic marine vertebrates, including: 1) Arctic residents with seasonal movements – those fishes, seabirds, and marine mammals that complete their entire life cycle within the Arctic but exhibit seasonal movements; 2) Breeding migrants – many seabirds enter the Arctic to breed and subsequently migrate south in the fall; and 3) Summer visitors for feeding – certain species of boreal fishes, seabirds and marine mammals arrive during the northern summer to feed on abundant prey though they breed elsewhere. Migratory movements are often driven by the timing and extent of sea ice, which defines suitable habitat for some animals and limits access to open water and prey for others. Longer open-water seasons, warmer ocean temperatures, and stronger winds have resulted in earlier production blooms in spring and often, extended open-ocean plankton blooms into late summer, resulting in altered prey types and distributions. A common thread among taxa is that shifts in distribution and timing of migrating animals indicate they are traveling farther north, or shifting longitudinally, and migrations are occurring over longer seasonal time frames. Species performing multiple lifetime migrations or long-distance migrants may need to adjust migration timing or routing iteratively to match changes in marine productivity. Altered animal distributions or phenology, and reduced sea ice, affects access to animals that are critical nutritional, economical, and cultural components of Indigenous people’s lives in the Arctic. Ongoing changes challenge the resilience and adaptability of Arctic people and ecosystems, and will require adaptive research and management approaches.

Movement behavior of satellite-tagged leatherback turtles from Panama in response to chlorophyll, primary productivity, temperature, and eddy kinetic energy

Leatherback turtles Dermochelys coriacea are globally endangered. This study tracked 30 individuals from the North Atlantic population tagged on the Caribbean Panama rookery (San San Pond Sak protected area, Bocas del Toro) over a period of 3 yr. We used satellite telemetry to investigate the probability that turtles switched between migration and foraging behavioral states as a function of environmental variables. We mapped the extensive migratory routes of these turtles and analyzed these using data derived from remote sensing, including chlorophyll, productivity, and sea surface temperature (SST), to assess how these influence their migratory and foraging behaviors. We also considered oceanographic processes, i.e. mesoscale eddies coinciding with the turtles’ migration paths, to understand their behavioral responses. Our observations revealed that while some turtles undertook extensive migrations to high-use areas in the Northeast and Northwest Atlantic, the majority remained within the boundaries of the Gulf of Mexico. The study effectively differentiated migration and feeding behavior, noting a clear positive relationship between feeding activities and chlorophyll concentration, while productivity played only a marginal role, and no influence was found for SST and mesoscale eddies. This study advances knowledge of North Atlantic leatherback turtle migrations, underscoring the importance of integrated, multidisciplinary marine conservation efforts. Understanding the impact of climate warming on migration paths and food source availability necessitates a holistic approach encompassing changes in physical oceanography, nutrient dynamics, and interactions from plankton to higher trophic levels. Additionally, as leatherback turtles traverse various international territories, the research emphasizes the need for collaborative data collection for their effective protection.

Discovery of the enigmatic taeniopterid plant Ilfeldia from the lower Permian of North China and its palaeophytogeographical implications

ABSTRACT The recognition of plant biogeographic ranges over time and migration routes is crucial for understanding ancient global plate tectonic configurations. This paper deals with a new fossil plant from the uppermost part of the Taiyuan Formation (earliest Asselian) in the Wuda Coalfield, Inner Mongolia, China. It has a taeniopterid morphology comprising strap-shaped leaves with a prominent midrib and arching secondary veins, and it exhibits dimorphism between its fertile and vegetative leaves. The fertile leaf has a slightly lobed margin, with each lateral vein terminating in a marginal lobe that bears a synangium. Each synangium consists of primarily two, occasionally three, oval sporangia. Based on these distinctive characteristics it is identified as a new species of Ilfeldia. Previously, Ilfeldia had a highly restricted record in the Upper Pennsylvanian of Portugal and Germany into the lower Permian of Germany. The sedimentary and floral context suggests Ilfeldia was a xerophilous element that underwent long-distance dispersal during the Late Pennsylvanian to earliest Asselian, migrating from Gondwana (Iberia) to Cathaysia (North China) via Euramerica (Eastern Avalonia). The palaeogeographical distribution over time of Ilfeldia supports the continental model of the Wegenerian Pangaea configuration and underscores the continental connection between Euramerica and Cathaysia in the Late Pennsylvanian.

The effect of mass migration on disease transmission: Evidence from the Venezuelan refugee crisis

AbstractSince 2014, millions of Venezuelans have fled to neighboring countries. There is only one accessible land crossing along the Brazil–Venezuela border (Pacaraima) and the Brazilian highway system limits migrants to one route through the Amazon for almost 1000 km. Using this event as a quasi‐random treatment, we find that refugee migration increased malaria incidence in Pacaraima, but this was limited to individuals of Venezuelan nationality. We find no effect on Brazilians in Pacaraima or in other municipalities along the main refugee migration route. We therefore reject the hypothesis that Venezuelan refugees increased the risk of malaria among native residents.

Baleen stable isotopes reveal climate-driven behavioural shifts in North Atlantic fin whales

Climate variability impacts the structure and functioning of marine ecosystems and can trigger behavioural responses in organisms. We investigated whether such variability modulates diet and migration in the North Atlantic fin whale (Balaenoptera physalus). To reconstruct the dietary and migratory behaviours over time, we conducted stable isotope analysis of nitrogen (δ15N) and carbon (δ13C) along baleen plates from 29 fin whales sampled off southwestern (SW) Iceland in summer. We estimated a baleen growth rate of 16.1 ± 2.5 cm per year from the stable isotope oscillations observed along the baleens. We also assigned a deposition date for each baleen segment, thus obtaining isotopic sequential time series. We then assessed the potential association of these time series with the main climate patterns of the North Atlantic basin. Baleen δ15N and δ13C values are associated with the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO). During high AMO and low NAO periods, which tend to decrease krill abundance, there is an increase in both the mean and standard deviation of baleen δ15N values, suggesting that fin whales shift to higher trophic resources and expand their dietary niche. Additionally, high AMO periods, which relate to positive temperature anomalies, lead to a decrease in baleen δ13C values, suggesting that fin whales adjust their migratory routes and destinations towards higher latitudes. Significant variation in isotopic niche width between years also reflected these dietary and migratory behavioural shifts. This highlights the plasticity of the North Atlantic fin whale behaviour, a trait likely to strengthen the resilience of the species within the current context of rapid and intense climate variability.

Migration and mobilisation in New York during the First World War

ABSTRACT This article examines the impact of the First World War on immigration into New York from 1914 into the 1920s. From the nineteenth century onwards, New York had become the destination for global migration as individuals sought to settle in the city or the wider United States. Millions had passed through the immigration points in New York by the beginning of the twentieth century but the outbreak of war in 1914 suddenly brought this flow to a halt. Naval blockades, restrictions on civilian movement and mobilisation of economies in Europe ended what had been one of the most significant migration routes in modern human history. The impact on the city of this curtailment brought fear and anxiety to the streets. New York’s population was overwhelmingly made up of first or second-generation immigrants in 1914 and a concern that the war could be ‘exported’ to the United States through New York created anti-immigrant concern amongst the city and federal authorities. This created a wartime culture in New York that – at least for the duration of the conflict – removed its status as a city of immigrants and instilled a sense that the metropolis should be remade as ‘American’.

Post-migration infection with SARS-CoV-2 in Venezuelan migrants: A laboratory-based epidemiological observational study

BackgroundSince 2015, over 6 million Venezuelans migrated to Colombia and neighboring countries. While most people adhered to lockdown measures, migrants kept moving during the COVID-19 pandemic. MethodTo investigate the extent of migration-associated SARS-CoV-2 infections, we interviewed 1209 adult Venezuelan migrants upon arrival to Bucaramanga, Colombia, 200 km from the Colombian-Venezuelan border along the main migration route during April–September 2021, collected individual-level socio-economic and clinical data, sampled blood and saliva, and assessed SARS-CoV-2 infection by serological, molecular and phylogenetic tools. ResultsSARS-CoV-2 RT-PCR positivity was 1.9 % (95 % Confidence Interval (CI), 1.2–2.9) without varying significantly over the study period (chi-square, p = 0.922) and significantly associated with stay in Colombia >14 days (p = 0.018; prevalence ratio 3.3, 95 % CI, 1.2–8.7). Pre-existing SARS-CoV-2-specific antibodies were neither significantly associated with preventing infection (Chi-square, p = 0.188), nor symptom development (Fisher, p = 0.246). Predominance and time of detection of SARS-CoV-2 Mu and Gamma variants in migrants in comparison to available genomic data suggested infection predominantly in Colombia. SARS-CoV-2 IgG-based seroprevalence was 34.2 % (95 % CI, 31.5–36.9). Detection of SARS-CoV-2-specific antibodies was significantly associated with previous contact with infected individuals (p = 0.002). ConclusionsSARS-CoV-2 infection occurred predominantly after immigration, potentially facilitated by densely populated border camps. Improved infrastructure and health care will prevent migration-associated spread of COVID-19 and other infectious diseases.

Dramatic recent declines in the size of monarch butterfly (Danaus plexippus) roosts during fall migration

The conservation status of monarch butterflies in North America is a topic of intense scrutiny and debate. It is clear that winter colonies in Mexico are declining, yet some recent studies suggest that summer breeding populations are relatively stable and similar to historical abundances. One possible explanation for these discordant patterns is that fall migration success has been recently disrupted. Here, we use a relatively unexplored citizen-scientist dataset on the size of monarch "roosts," which are resting aggregations on vegetation, to infer changes in monarch abundance along the fall migration route over the last 17 y. We found that the timing of migration remained relatively unchanged while the flyway has generally become warmer and greener. Warmer and greener conditions were associated with larger roosts, yet we found steady, dramatic declines in roost sizes through time that were independent of climate and landscape factors. Roost sizes have declined as much as 80%, with losses increasing from north to south along the migration route. These findings suggest that failure during the fall migration could explain the apparent drop in monarch numbers from summer breeding to overwintering populations. This in turn suggests that conservation efforts that support fall migration success are most needed, such as providing high quality nectar plants along the migration route or limiting the planting of nonnative milkweeds that enhance monarch parasite loads. Overall, it appears the fall migration of monarch butterflies is under imminent threat, even if the species' overall survival is not.

Migratory strategies across an ecological barrier: is the answer blowing in the wind?

BackgroundEcological barriers can shape the movement strategies of migratory animals that navigate around or across them, creating migratory divides. Wind plays a large role in facilitating aerial migrations and can temporally or spatially change the challenge posed by an ecological barrier, with beneficial winds potentially converting a barrier into a corridor. Here, we explore the role wind plays in shaping initial southbound migration strategy among individuals breeding at two sites along an ecological barrier.MethodsUsing GPS satellite transmitters, we tracked the southbound migrations of Short-billed Dowitchers (Limnodromus griseus caurinus) from two breeding sites in Alaska to nonbreeding sites in coastal Mexico. The breeding sites were positioned in distinct regions along an ecological barrier – the Gulf of Alaska. We investigated potential differences in migratory timing, wind availability, and tailwind support en route across the Gulf of Alaska between individuals breeding at the two sites.ResultsRoute choice and arrival timing to wintering sites differed markedly between the two breeding sites: individuals departing from the more westerly site left at the same time as those from further east but crossed the Gulf of Alaska farther west and arrived along the Pacific coast of Mexico an average of 19 days earlier than their counterparts. Dowitchers from both sites departed with slight tailwinds, but once aloft over the Gulf of Alaska, birds from the more westerly site had up to twelve times more tailwind assistance than birds from the more easterly one.ConclusionsThe distinct migration strategies and degree of wind assistance experienced by birds at these two breeding sites demonstrates how differences in wind availability along migratory routes can form the basis for intraspecific variation in migration strategies with potential carryover effects. Future changes in wind regimes may therefore interact with changes in habitat availability to influence migration patterns and migratory bird conservation.

Differential Experiences of Displacement in Transit through Mexico. The Ethnic Bridges among Garífuna and Honduran-Latino Groups

This article focuses on the differential experiences of migratory displacement between two ethnic groups from Honduras; the Afro-American Garifuna and Latinos. It seeks to compare the differential migration strategies of these two ethnically distinct displaced populations from the same country. Both move towards the same destination starting with transit through Mexico and then attempting to reach the United States. The manuscript is based on fieldwork conducted in migrant shelters within the irregular migratory route in Mexico, also, in New Orleans and Houston, two major destinations for the Garifuna population in the U.S. The paper consequently focuses on the case of the Garifuna, for whom it identifies the processes of territorial exclusion in which they are involved from the origin, nevertheless put the Garifuna population at an advantage over their non-Garifuna countrymen Latinos concerning the migratory process and their migration networks, specifically for having a better previous integration in the country of destination.

Imported malaria cases by Plasmodium falciparum and Plasmodium vivax in Mexican territory: Potential impact of the migration crisis

BackgroundAs the migratory flow to the USA has intensified in recent months, health problems associated have been identified. The aim of this work was the identification of malaria cases imported into Mexican territory. MethodsOperational definitions of suspected and confirmed cases were used for investigation of malaria cases. Detection of parasitic entities by thick blood smear and molecular biology served as a confirmatory test. With the characteristics of the cases, a heat map was made to determine common clinical pictures. Finally, epidemiological analysis of cases was performed for the construction of timelines of imported malaria and the tracing of migratory routes. ResultsTwelve migrants from four countries were treated for presenting clinical symptoms with suspected dengue or malaria. Malaria was confirmed and two Plasmodium species were identified. From the epidemiological dates of arrival in Mexico, onset of symptoms and migratory routes, we speculate that ten cases acquired P. vivax during their crossing through Honduras, El Salvador or Guatemala. For the Guinea cases, we conclude that there was African importation of P. falciparum. ConclusionThe epidemiological panorama of malaria cases imported into Mexico show the need to join efforts to ensure universal access to health services, with the objective of timely detection of imported cases.

Determining the Fish Migration Patterns Based on Fish Habitat Assessment at a River Confluence

ABSTRACTMuch effort has been devoted to predicting fish migration routes to assist target species migration, and yet, fish migration science and practice remain imperfect. This study aimed to predict the migration paths of Gymnocypris przewalskii at the river confluence in the Qinghai Lake basin. The authors proposed an approach for fish migration route prediction, which involves a hydrodynamic module, a habitat model and a fish migration module. The TELEMAC‐MASCARET system was used to simulate hydrodynamic conditions and statistical analyses were carried out. During the flood season, G. przewalskii migrates downstream, whereas during the migratory season, they migrate upstream. The results indicate that flow velocity was the most significant hydrodynamic parameter affecting fish migration behaviour. The optimal flow velocity range for the target fish species was between 0.7 and 1.7 m/s. The impact of water depth was only observed in low discharge situations. Besides, the temperature plays a vital role in determining fish migration and abundance. However, the results reveal that in the morning hours, the temperature exhibits a range of 10°C to 16°C, and in the noon, the average temperature ranges from 16°C to 19°C, with a maximum temperature reaching 23°C. These temperature variations enable fish to migrate towards the tributary offering a more favourable water temperature during route selection at a river confluence. The study concludes that future research should consider incorporating the swimming capacity of the focal fish species to provide insights into fish migration patterns.

Do African Savanna Elephants (Loxodonta africana) Show Interspecific Social Long-Term Memory for Their Zoo Keepers?

"An elephant never forgets" is a popular phrase that refers not only to the elephant's extraordinary ability to remember migration routes but also to its pronounced social long-term memory (SLTM). Previous studies have shown intra- and interspecies SLTM performance, but the ability of elephants to have memories of individual humans has not yet been investigated. We tested this interspecific SLTM using auditory, olfactory, and visual stimuli, each from familiar and unfamiliar persons, in two African savanna elephant (Loxodonta africana) cows living in a zoo. The two-choice object tests revealed a higher interest in sensory stimuli from familiar keepers they had not seen for 13 years than in unfamiliar people. Statistically significant differences were found for olfactory stimuli. In addition, there was significantly more interest in visual stimuli from current keepers than in stimuli from unfamiliar people. Contrary to the results of a previous study with elephants, this was not observed for olfactory stimuli. Due to the small sample size and magnitude of the influencing factors, that is, outdoor experiment, only spatial separation of the animals, these results only represent indications of the possible interspecific SLTM. Nevertheless, we were able to provide the first empirical evidence that L. africana stores information about specific people over a long period of time. Further studies with larger sample sizes, cross-modal testing, and people disliked by the elephants could provide more insights.

Microbiome Geographic Population Structure (mGPS) Detects Fine-Scale Geography.

Over the past decade, sequencing data generated by large microbiome projects showed that taxa exhibit patchy geographical distribution, raising questions about the geospatial dynamics that shape natural microbiomes and the spread of antimicrobial resistance (AMR) genes. Answering these questions requires distinguishing between local and non-local microorganisms and identifying the source sites for the latter. Predicting the source sites and migration routes of microbiota has been envisioned for decades but was hampered by the lack of data, tools, and understanding of the processes governing biodiversity. State-of-the-art biogeographical tools suffer from low resolution and cannot predict biogeographical patterns at a scale relevant to ecological, medical, or epidemiological applications. Analyzing urban, soil, and marine microorganisms, we found that some taxa exhibit regional-specific composition and abundance, suggesting they can be used as biogeographical biomarkers. We developed the Microbiome Geographic Population Structure (mGPS), a machine-learning-based tool that utilizes microbial relative sequence abundances to yield a fine-scale source site for microorganisms. mGPS predicted the source city for 92% of the samples and the within-city source for 82% of the samples, though they were often only a few hundred meters apart. mGPS also predicted soil and marine sampling sites for 86% and 74% of the samples, respectively. We demonstrated that mGPS differentiated local from non-local microorganisms and used it to trace the global spread of AMR genes. mGPS's ability to localize samples to their waterbody, country, city, and transit stations opens new possibilities in tracing microbiomes and has applications in forensics, medicine, and epidemiology.

Criminal Legal Steps to Stop the Irregular Migration in Hungary

Abstract From 2015, migratory pressures put a heavy burden on EU countries. In 2015, Hungary took a new approach by building a border fence and creating criminal legal rules to protect it. This study aims to assess these measures in the EU sphere. Our research was based on EU (frontex) and national (Prosecutor General’s Office information) data and assessed the Hungarian solution in the light of the migration policy of other Member States located along the main migratory routes. The data show: (1) the criminal law has no substantive effect, and (2) the law enforcement tools are effective. Moreover, the domestic data also show that Hungary is not consistent in its policy and has preferred law enforcement tools to criminal legal tools in the past few years, which violates the basic principles of criminal law: the principle of legality and the principle of ultima ratio.

Ascaris in infected pancreatic necrosis: A case report of an intraoperative surprise

Introduction and Importance: Ascariasis lumbricoides is a common gastrointestinal tract helminthic disease in developing countries and is also a cause of hepatobiliary and pancreatic disease in endemic areas of the world. Involvement of the pancreatic duct by worms and associated pancreatitis is less common than the hepatic and biliary involvement. Case Presentation: A 38-year-old patient was admitted with a diagnosis of alcohol-induced acute pancreatitis and managed conservatively. However, the patient’s condition worsened after two weeks, and a CT scan revealed an acute necrotic collection with gas foci. After failed percutaneous pigtail catheter drainage, laparotomy was performed, revealing a necrotic collection in the right paracolic gutter, with the entire area frozen, and a worm observed in the necrosum. The colon and small bowel were intact without perforation. The suspicion arose that the worm might have either migrated from a duodenal perforation, which had possibly sealed after the acute phase, or migrated from the major pancreatic duct. Debridement of easily accessible necrotic tissues was performed, and the patient was admitted to the intensive care unit (ICU). Unfortunately, the patient tested positive for COVID-19, and a few days later, blood was observed in the drain. Re-exploration revealed diffuse blood oozing, and the abdomen was closed with packing. Conclusion: The route of ascaris migration to necrosum or its association with severe acute pancreatitis needs to be ensured in endemic areas. Cautious use of antihelminthic therapy in endemic areas could prevent fatal pancreatobiliary complications and its associated mortality.

Polish Conductresses and the Insecurities of Female Labour Migration to France, 1925–1929

In this article we argue that the reports of conductresses accompanying female migrants shed new light on the nature of interwar labour migration. As they mitigated the anxiety and insecurity that women faced during the process of migration, they fulfilled a crucial role in the highly restrictive post-1918 international migration regime. The Polish government introduced conductresses in 1925 to respond to news of the mistreatment and sexual exploitation of Polish women working in France. Developed in close collaboration with international organizations and the League of Nations, the work of these conductresses on land and sea routes was framed as those of ‘moral guardians’ protecting female migrants from the dangers of sex trafficking. However, we argue that their main function was to mitigate the uncertainties of the post-war international order, as traditional routes of migration were ruptured and both dispatching and receiving countries attempted to control and restrict migration. Female migrants had no networks with existing diasporas, were often illiterate, and mistrusted both Polish and French institutions. By addressing these challenges, the conductresses took on roles far beyond their function as moral authority: they acted as translators, knowledge imparters, mediators, and network forgers. Both in Poland and at the international level, the Polish conductress scheme was regarded a success, as they managed to provide a relatively ‘secure’ migration experience within a migration regime designed to walk a fine line between demands for foreign labour on the one hand and the rising ideal of economic protectionism on the other.

AVIAN HAEMOSPORIDIANS IN GREATER SCAUP (AYTHYA MARILA) AND LESSER SCAUP (AYTHYA AFFINIS) FROM WISCONSIN.

Avian haemosporidians are a diverse group of protozoan parasites that infect a wide range of host species. Waterfowl are an ecologically and economically important group of hosts that have been underrepresented in studies of haemosporidians. Diving ducks have unique life history traits, and morphological, behavioral, and dietary differences separate them from more common dabbling ducks. Greater scaup (Aythya marila) and lesser scaup (Aythya affinis) are closely related diving ducks with declining population trends in North America. To better understand the diversity of haemosporidians within diving ducks and factors related to host infections in scaup, we surveyed 82 hunter-donated waterfowl from 8 species of divers, sea ducks, and dabblers from Green Bay, Wisconsin from 2019 to 2021. We used molecular detection methods and phylogenetic and statistical analyses to describe the diversity, host associations, and prevalence of haemosporidians. We detected 14 unique genetic lineages of haemosporidians, including 4 novel lineages. We identified at least 1 lineage of haemosporidian in each of the 8 host species of divers, sea ducks, and dabblers examined. Lesser scaup had more diverse haemosporidian communities than did greater scaup, but lineages showed no clustering among these hosts when incorporated in phylogenetic analyses with lineages from other Nearctic waterfowl. Female lesser scaup had the highest infection prevalence, but there was no effect of host age or year of sampling. Our findings underscore the importance of species and sex differences that could lead to a higher risk of infections. Our results also fill an important geographical sampling gap for haemosporidians along a key migratory route. Increased monitoring of haemosporidians in waterfowl could contribute to insights into parasite evolution and ecology and the conservation and management of host populations.