Heath Hagy

• University of Illinois Urbana-Champaign

The miniaturization of Global Positioning Systems (GPS) transmitters is providing insights into the ecology and management of migratory bird species at biologically‐relevant spatial scales. However, transmitters and their attachment methods could bias inferred behaviors, demographic rates, and resulting management decisions. We evaluated the effect...

The energy derived from available foods is an important factor used in conservation planning for migratory species. Estimating true metabolizable energy (TME) of available foods has become a common method for resource managers to increase reliability in energetic carrying‐capacity estimates. Lesser scaup (Aythya affinis; hereafter scaup), have expe...

The equilibrium theorem provided a fundamental framework for understanding species’ distributions and movement in fragmented ecosystems. Wetland-dependent avian species are model organisms to test insular predictions within protected area networks because their mobility allows surveillance of isolated patches without landscape barriers. We hypothes...

Extreme climatic events (ECEs) can have profound impacts on individual fitness, affecting survival directly or indirectly. Late winter ECEs may be especially detrimental to fitness due to limited food resources and increased energetic requirements during this time. A polar vortex disruption ECE descended upon the mid-continental United States durin...

Our aim was to describe shifts in autumn and winter harvest distributions of three species of dabbling ducks (blue‐winged teal [Spatula discors], mallard [Anas platyrhynchos], and northern pintail [Anas acuta]) in the Central and Mississippi flyways of North America during 1960–2019. We measured shifts in band recovery distributions corrected for c...

Conservation planners use bioenergetic models to develop habitat objectives that satisfy energetic demands of waterfowl during nonbreeding periods. In turn, natural resource managers should estimate yield and availability of natural and cultivated waterfowl forage to monitor contributions to objectives and support adaptive resource management. Beca...

Animals balance costs of antipredator behaviors with resource acquisition to minimize hunting and other mortality risks and maximize their physiological condition. This inherent trade‐off between forage abundance, its quality, and mortality risk is intensified in human‐dominated landscapes because fragmentation, habitat loss, and degradation of nat...

The spatiotemporal allocation of activity is fundamental to how organisms balance energetic intake and predation risk. Activity patterns fluctuate daily and seasonally, and they are proximately affected by exogenous and endogenous conditions. For birds, flight activity is often necessary for relocating between foraging patches but is energetically...

Public lands managed for wildlife frequently provide various forms of sanctuary to increase residency times and allow access to energetic and other habitat resources for waterfowl. The influence of sanctuary type and disturbance regime on resource use and fine‐scale movements of waterfowl has not been investigated extensively using currently availa...

Nutrients acquired by ducks on spring migratory stopover areas influence survival and subsequent reproduction. Accordingly, wetland loss and degradation on stopover areas can lead to reduced refueling efficiency and have demographic consequences. Lipid metabolite concentrations in blood provide a useful index of daily mass change in wild birds and...

Geographical distributions of waterfowl exhibit annual variation in response to spatiotemporal variation in weather conditions, habitat availability, and other factors. Continuing changes in climate and land use could lead to persistent shifts of waterfowl distributions, potentially causing a mismatch with habitat conservation planning, wetland res...

Avian influenza viruses pose a threat to wildlife and livestock health. The emergence of highly pathogenic avian influenza (HPAI) in wild birds and poultry in North America in late 2021 was the first such outbreak since 2015 and the largest outbreak in North America to date. Despite its prominence and economic impacts, we know relatively little abo...

The North American Waterfowl Management Plan (NAWMP) recognizes waterfowl hunters and non-consumptive users as important stakeholders to sustain waterfowl populations through economic and political support for habitat conservation initiatives. Opportunities to shoot at and harvest ducks are key determinants of achievement-oriented hunt satisfaction...

Migratory waterfowl (i.e., ducks, geese, and swans) management relies on landscape bioenergetic models to inform on-the-ground habitat conditions and conservation practices. Therefore, conservation planners rely on accurate predictions of wetland habitats for waterfowl at regional scales. Unharvested flooded corn is a popular management tool on pub...

Our collective understanding of secretive marsh birds has increased in the past decades due to the development and implementation of the North American Standardized Marsh Bird Monitoring Protocol (hereafter, Protocol). The Protocol proposes call broadcast surveys to increase vocalization and detection rates within 3 standardized survey periods aime...

Wildlife harassment (i.e., intentional disturbance by humans) is a common nonlethal management approach employed to reduce human‐wildlife conflicts, but effectiveness is often undocumented or uncertain. We evaluated the effect of harassment on Canada goose ( Branta canadensis ) behavior in an urban area during winter. Winter can be a challenging pe...

Global climate change is increasing the frequency and severity of extreme climatic events (ECEs) which may be especially detrimental during late‐winter when many species are surviving on scarce resources. However, monitoring animal populations relative to ECEs is logistically challenging. Crowd‐sourced datasets may provide opportunity to monitor sp...

The Mississippi Flyway supports millions of waterfowl during spring migration as individuals replenish vital nutrients en route to breeding locations. Green-winged teal Anas crecca consume natural plant and animal foods in shallow wetlands during autumn and winter, but little information is available to describe food use and selection during spring...

Although most emergent wetlands across central North America have been destroyed or degraded, wetland restoration in recent decades has provided new habitat resources for wetland birds in agriculturally dominated landscapes. The goals of wetland restorations often include providing habitat for migratory and breeding waterfowl and other wetland bird...

Energy acquisition and storage are important for survival and fecundity of birds during resource-limited periods such as spring migration. Plasma-lipid metabolites (i.e. triglyceride [TRIG], β-hydroxybutyrate [BOHB]) have been used to index changes in lipid stores and, thus, have utility for assessing foraging habitat quality during migration. Howe...

Aerial surveys for waterfowl and other waterbirds provide abundance estimates that are commonly used by state and federal agencies for waterfowl and wetland management. However, most existing surveys provide an index of abundance and are uncorrected for visibility bias, which may limit their use in accurately determining local population size. We u...

Wetland-dependent bird populations may be limited by habitat in regions where wetland loss and degradation are pervasive, such as the midwestern United States. However, available spatial datasets, such as the National Wetlands Inventory (NWI), may overestimate habitat availability if total wetland area includes wetlands unsuitable for wetland-depen...

Aerial surveys flown at low altitudes allow detection, identification, and enumeration of waterfowl and other waterbirds, but few studies have assessed disturbance to these guilds during the nonbreeding period. Excessive disturbance can potentially increase energy expenditure and exposure to hunting mortality contrary to objectives of many waterfow...

Marsh birds (rallids, bitterns, and grebes) depend on emergent wetlands, and habitat loss and degradation are the primary suspected causes for population declines among many marsh bird species. We evaluated the effect of natural wetland characteristics, wetland management practices, and surrounding landscape characteristics on marsh bird occupancy...

Avian diet quality is typically measured using true metabolizable energy (TMEN), which is a measure of assimilable energy of food items accounting for innate endogenous losses. Because there is little knowledge of the variation in TMEN estimates among food items and waterfowl species, we investigated TMEN of 6 common species of submersed aquatic ve...

Stopover sites provide crucial habitat for waterfowl to rest and refuel during migration. Knowledge of which land-cover types are of greatest importance to migrating waterfowl and how the surrounding landscape influences their use can inform management decisions and conservation plans to adequately meet resource requirements. Specifically, spring m...

Spring migration is an energetically demanding event that can impact nutrient dynamics of individuals during the breeding season through carry-over effects. Limited food availability at spring stopover areas may have cross-seasonal effects that adversely impact waterfowl populations. We collected 161 Green-winged Teal (Anas crecca Linnaeus, 1758; h...

Waterfowl use stopover sites during spring migration to rest and replenish nutrient reserves prior to their arrival on breeding grounds. Estimating the extent to which an individual remains at a stopover site before dispersing (i.e., stopover duration) is essential for managers to develop wetland habitat objectives needed to ensure sufficient resou...

Intensification of land use practices and climate change have resulted in extensive wetland loss and declines of native submersed aquatic vegetation (SAV) species across North America. Limited by a lack of biomass and energy estimates for wetlands containing SAV, conservation planners currently are unable to accurately account for its energetic con...

The adaptation of birds to urban environments has created direct hazards to air transportation with the potential for catastrophic incidents. Bird–aircraft collisions involving Canada geese (Branta canadensis; goose) pose greater risks to aircraft than many bird species due to their size and flocking behavior. However, information on factors drivin...

True metabolizable energy (TME) of waterfowl foods is commonly estimated for use in energetic carrying capacity models in association with conservation planning efforts under the North American Waterfowl Management Plan. Researchers define and estimate TME as the net energy from excreta collected from an individual after feeding a precise quantity...

Water hyacinth (Eichhornia crassipes) is an invasive aquatic macrophyte that is prolific throughout many regions worldwide, but it has recently been detected in several areas of the Midwest United States, outside of its historical range. We assessed the occurrence of water hyacinth in the upper Illinois River to understand the current distribution...

Numerous organisms exhibit carry-over effects, in which previous environmental conditions impact current performance. For example, reproductive output for many migratory birds can be impacted by events during the preceding migration. Lesser Scaup (Aythya affinis (Eyton, 1838); hereafter scaup) declined dramatically during 1970s–2000s, and there is...

Thousands of lesser scaup (Aythya affinis) die during spring and fall migrations through the upper Midwest, USA, from infections with Cyathocotyle bushiensis and Sphaeridiotrema spp. (Class: Trematoda) after ingesting infected intermediate hosts, such as non-native faucet snails (Bithynia tentaculata). The lesser scaup is a species of conservation...

Modifications of the Illinois River and associated tributaries have resulted in altered hydrologic cycles and persistent river‐floodplain connections during the growing season that frequently impede the establishment of hydrophytic vegetation and have reduced value for migratory waterfowl and other waterbirds. To help guide floodplain restoration,...

Some fish are important dispersal vectors of aquatic plants (i.e., ichthyochory), yet few examples have been documented outside of the Neotropics. Although highly modified and degraded, the upper Illinois River Waterway supports common carp (Cyprinus carpio) populations and abundant aquatic vegetation. As common carp have been previously documented...

Wetland restoration in highly modified landscapes involves balancing target ecosystem functions and values with constraints of landscape and stakeholder context. Often, a restored wetland complex cannot meet all target conditions simultaneously, and tradeoffs must be understood, evaluated, and quantified. We examined the tradeoff between providing...

The Nature Conservancy’s wetland restoration at the Emiquon Preserve has been a success to date, but there are warning signs of undesirable change if left unmanaged. A water control structure built in 2016 will increase management capabilities, but periodic connection to the river, which has experienced human alterations typical of rivers in easter...

More than half of the natural wetlands in the Illinois River valley (IRV) have been lost through conversion of floodplain wetlands and lakes to drainage and levee districts for agricultural production. During 2007–2013, we monitored the response of wetland vegetation communities to restoration at Emiquon Preserve, a former floodplain that was drain...

Despite extensive anthropogenic degradation of most wetlands and other aquatic habitats associated with large rivers in the Midwest, the region still supports continentally important numbers of waterbirds during autumn and spring migration; however, few data exist to evaluate wetland restoration success and identify thresholds where changes in mana...

The flood pulse drives primary productivity, biotic communities, and abiotic processes in large river systems; however, the effects of floods on restored floodplain lakes and associated wetlands are poorly understood. Record flooding of the Illinois River, Illinois, in 2013 reconnected two floodplain preserves under restoration that had been discon...

Winter distribution and resource use of animals is driven by myriad interacting biotic and abiotic factors. Urban areas provide sanctuaries from hunting for game animals and may have thermal benefits during winter through reduced thermoregulatory costs. We deployed cellular GPS transmitters affixed to neck collars of 41 Canada Geese (Branta canaden...

Probability-based sampling designs for aerial surveys are useful for estimating wintering waterfowl abundances in large areas with contiguous habitat (e.g., Mississippi Alluvial Valley). The effectiveness of these approaches for estimating abundance of nonbreeding waterfowl in small areas with discontinuous habitat has rarely been assessed. Surveys...

The Illinois River Valley (IRV) in central Illinois, USA, provides migratory stopover habitat for millions of waterfowl during autumn and spring in the Mississippi Flyway. Mallards (Anas platyrhynchos) are the most abundant species of waterfowl during autumn migration and the most harvested duck in Illinois. We investigated mallard migration ecolog...

Aerial surveys are a valuable tool for monitoring wildlife and their habitats throughout North America, but manned aerial surveys for monitoring aquatic vegetation communities have seldom been evaluated rigorously. We used a fixed-wing aircraft and modified double observer method to survey an invasive aquatic macrophyte, water hyacinth (Eichhornia...

Soulliere, G. J., M. A. Al-Saffar, J. M. Coluccy, R. J. Gates, H. M. Hagy, J. W. Simpson, J. N. Straub, R. L. Pierce, M. W. Eichholz, and D. R. Luukkonen. 2017. Upper Mississippi River and Great Lakes Region Joint Venture Waterfowl Habitat Conservation Strategy – 2017 Revision. U.S. Fish and Wildlife Service, Bloomington, Minnesota, USA.

The interaction of animals with their food can yield insights into habitat characteristics, such as perceived predation risk and relative quality. We deployed experimental foraging patches in wetlands used by migrating dabbling ducks (Anas spp.) in the central Illinois River Valley to estimate variation in seed removal and giving-up density (GUD; i...

We examined the associations between intestinal helminth infracommunity structure and infection parameters and the age, size, and year and region of collection of 130 female lesser scaup (Aythya affinis) during their 2014–2015 spring migrations through the upper Midwest, USA.We identified a total of 647,174 individual helminths from 40 taxa, includ...

Scientists estimate biomass of invertebrates to evaluate wetland management practices, estimate energetic carrying capacity for wildlife, assess habitat condition and disturbance, and quantify ecosystem services. For waterfowl and other waterbirds in North America, carrying capacity in migratory and wintering regions is estimated using food density...

ABSTRACT.—The Illinois River historically provided high-quality habitat for a variety of migratory birds but sedimentation, management for commercial navigation, and increasing hydrologic variability have contributed to reductions in aquatic vegetation and naturally occurring foods for waterfowl. Cover of aquatic vegetation within the Illinois Rive...

Historically, Thompson and Flag Lakes, were among the most productive freshwater systems in the country. Additionally, they provided habitat for a tremendous number of water fowl and migrating bird species. In the 1920’s, these lakes were drained and the land converted over to agriculture production. In 2007, The Nature Conservancy (TNC), establish...

Energetic carrying capacity of habitats for wildlife is a fundamental concept used to better understand population ecology and prioritize conservation efforts. However, carrying capacity can be difficult to estimate accurately and simplified models often depend on many assumptions and few estimated parameters. We demonstrate the complex nature of p...

This paper summarises discussions by invited speakers during a special session at the 6th North American Duck Symposium on wetland issues that affect waterfowl, highlighting current ecosystem challenges and opportunities for the conservation of waterfowl in North America. Climate change, invasive species, U.S. agricultural policy (which can encoura...

Major floods elicit calls for more comprehensive and multi-faceted approaches to flood management. In the future, adding floodways and flood storage areas to traditional structural strategies (e.g. dams and levees) may be a viable strategy. Beyond reducing flood damages, there is growing societal interest in floodplain services, including nutrient...

Estimates of time spent at migratory stopovers are often used to develop habitat conservation objectives for a variety of avian species, namely waterfowl. Because of limited previous research and a need for accurate conservation planning objectives, we estimated stopover duration and factors influencing stay of mallards (Anas platyrhynchos) in Illi...

Population-based habitat conservation planning for migrating and wintering waterfowl in North America is carried out by habitat Joint Venture (JV) initiatives and is based on the premise that food can limit demography (i.e. food limitation hypothesis). Consequently, planners use bioenergetic models to estimate food (energy) availability and populat...

Spatial and temporal heterogeneity in habitat quantity and quality, weather and other variables influence the production of food and the distribution of waterfowl, making it difficult to predict carrying capacity accurately. Food densities for waterfowl, which are key parameters of energetic carrying capacity models, were examined in managed moist-...

Wetlands are highly productive ecosystems that provide habitat for a diversity of wildlife species and afford various ecosystem services. Managing wetlands effectively requires an understanding of basic ecosystem processes, animal and plant life history strategies, and principles of wildlife management. Management techniques that are used differ de...

Managed moist-soil wetlands are important habitats for waterfowl and other waterbirds in the Mississippi Alluvial Valley (MAV) and elsewhere in North America. These wetlands often contain abundant food resources, but they also contain tall and dense (i.e., robust) vegetation that may constrain use and foraging by waterbirds. During winters 2006–200...

Scientists, conservation planners, and resource managers who estimate energetic carrying capacity of foraging habitats for wintering waterfowl require accurate data on food availability and use. We estimated seed and tuber abundance in moist-soil wetlands commonly used and foraged in by dabbling ducks (Anas spp.) in and near the Mississippi Alluvia...

Moist-soil wetlands are seasonally flooded areas that produce early-succession plant communities of grasses, sedges, and other herbaceous plants. Moist-soil wetland plants provide food and cover for a diversity of wildlife species, including waterfowl and other waterbirds. Thus, conservation and management of moist-soil plants has become a major co...

Even though avian damage to sunflower (Helianthus annuus L.) is a worldwide economic issue, several of the current methods used to reduce sunflower damage were developed and tested in the Prairie Pothole Region of the United States. An intensive research program was conducted in that area because of the regionalized concentration of sunflower produ...

Studies describing food use (i.e., diet) of nonbreeding dabbling ducks Anas spp. are essential to understanding physiological needs of and recommending habitat management for these birds. We conducted a review of published autumn and winter food-use studies of dabbling ducks in North America to characterize the current state of knowledge and identi...

Scientists estimate seed abundances to calculate seasonal carrying capacities and assess wetland management actions for waterfowl and other wildlife using soil core samples. We evaluated recovery of known quantities of moist-soil seeds from whole and subsampled experimental core samples containing 12 seed taxa representing small, medium, and large...

Agricultural fields are often overlooked as post-breeding and migratory bird habitat, even though many species use row-crop fields in the northern Great Plains. We monitored bird use, crop and non-crop vegetation characteristics and abundance, and land use around (≤2.4 km) 35 8-ha Wildlife Conservation Sunflower Plots (WCSP) and one commercial sunf...

In 2004, USDA's Wildlife Services began to cost share 8-ha Wildlife Conservation Sunflower Plots (WCSP) with sunflower growers to lure migrating blackbirds away from commercial sunflower fields. During late summer and fall of 2004 and 2005, blackbirds used sunflower more than other crops, especially WCSP placed near blackbird roosts. Blackbird dens...

Wildlife conservation sunflower plots (lure plots) are used to protect high value oil and confectionery sunflower. Lure plots are used to draw blackbirds away from commercial fields to reduce sunflower damage. From 2004-2007, USDA Wildlife Services funded a pilot program for growers to plant 20-acre lure plots to test their effectiveness for reduci...

In North Dakota, annual blackbird damage to sunflower ranges from $5-10 million. Blackbird damage to ripening sunflower has forced some growers to plant alternative crops. From 2004 to 2006, USDA-Wildlife Services cost-shared Wildlife Conservation Sunflower Plots (WCSP) with sunflower growers. The objective of the WCSP was to provide blackbirds an...

The northern Great Plains are home to a variety of birds throughout the year, particularly during migration. Migratory species use native and restored grasslands, shelterbelts, and agricultural fields for food and shelter in North ,Dakota. Blackbirds ,(Xanthocephalus xanthocephalus) have been documented,to cause economically important damage,to som...

Wildlife Conservation Sunflower Plots (WCSP) were planted and monitored during a two-year trial/research program to monitor the effect of decoy plots on blackbird use of nearby commercial sunflower and abundance of nonblackbird migratory species within the plots. In the two year evaluation period, in excess of 975 hours were spent by three research...

In an effort to reduce blackbird damage to commercial sunflower, which can range from $4-11 million annually in North Dakota and South Dakota, we evaluated Wildlife Conservation Sunflower Plots (WCSP) for efficacy and wildlife benefits. Blackbird depredation has caused some producers to reduce sunflower acreages and seek alternative crops in this o...

North Dakota and South Dakota produce about 70% of the sunflower grown in the United States. Blackbird depredation, particularly in the Prairie Pothole Region (PPR), can be a major problem that results in some producers abandoning sunflower. Reduced acreage of an otherwise profitable crop is important economically and might harm migratory bird popu...