Notes from the Field: Eastern Mallard Project

“Notes From the Field” news articles highlight the continued importance of bird banding. This article was contributed by Abbey Butler, John Coluccy, Daria Sparks, Josh Stiller, Jacob Straub, Cassidy Waldrep, and Mitch Weegman, key researchers of the Eastern Mallard Project, established in 2022.  

Today, banding allows scientists to investigate bird behavior, migration, lifespans, populations, diseases and levels of environmental contaminants. Information gathered through the North American Bird Banding Program helps inform management and conservation decisions for game and non-game species, such as protecting or restoring habitat, setting hunting regulations and determining plans for human-led development. The North American Bird Banding Program depends on a network of over 10,000 permitted bird banders working in the United States, Canada and Trust Territories. Each year these banders help contribute up to 1.2 million new banding records to our century-long dataset. 

What is your bird banding/marking project?   

The Eastern Mallard Project was designed to comprehensively study drivers of reproductive success, survival, and habitat use throughout the full annual cycle. Eastern mallards nest in eastern Canada and the northeastern US. The subpopulation of birds nesting in eastern Canada is relatively stable, but the mallard subpopulation nesting in the northeastern US appears to be declining. There are several likely contributors to the differences between these breeding populations, including differences in breeding habitat quality, land use change between countries, and/or study design differences between surveys in each country. To better understand these potential contributing factors, our team members are deploying ~1,200 GPS-acceleration (behavioral) tracking devices on female mallards across four winter seasons, an effort which began in early 2022. Birds fitted with these devices during winter will ultimately nest across eastern Canada and the northeastern US, providing unique insights into the subpopulation patterns. The devices are manufactured by Ornitela and weigh 20 g. We are also deploying geolocators (light sensors, weighing 3 g) on plastic leg bands fitted to female mallards without Ornitela tracking devices, so that we can compare movement, survival and reproductive success between birds with each device type. These comparisons will allow us to contextualize any potential effects of the tracking devices on individual behavior, habitat use, or nesting success. As of the end of 2024, we have deployed 974 transmitters and 887 geolocators. We hope to deploy an additional 270 transmitters and 395 geolocators in the winter of 2025. 

The transmitters record GPS data every hour, while the acceleration data (movement in all three axes) are recorded for three seconds every 10 minutes. GPS and acceleration data are uploaded daily via the Global System for Mobile Communication (i.e., cell phone) network. If tagged birds are not in range of a cell phone tower, the units will store data for up to 6 months. The GPS-acceleration devices are solar powered and expected to last 2-3 years.   

The geolocators record light level data every five minutes. However, in contrast to the transmitters, the geolocator must be recaptured or recovered for researchers to download the data. Using light-level data and information about timing of sunrises and sunsets, we can estimate the location of the bird during the period of data collection.   

Female mallard with geolocator attached to left leg. This device records light level data. Photo courtesy of Ryan Campbell. 

How/why was this project started? What question(s) are you trying to answer through your research? 

This project was initiated to understand the factors contributing to the declining subpopulation of eastern mallards nesting in the northeastern US when compared to the stable subpopulation of eastern mallards in eastern Canada. An underlying factor of these population patterns is variability in survival and reproductive success. We hypothesize that differences in demographic rates between subpopulations will explain the different subpopulation trajectories. The GPS-acceleration tracking devices provide high resolution information in space and time, which allows for detailed study of individual bird decisions that can be propagated to the population level. Because contributing factors to the different population trajectories could be compounding throughout the year, we are taking a comprehensive approach by studying habitat use, reproductive success and survival, and comparing seasonal patterns within and between years. 

How does banding/marking help you answer your research questions and achieve objectives?  

We anticipate that the high-resolution GPS and acceleration data will allow us to understand the relative contributions of individual bird decisions, such as movement, behavior, and habitat use, throughout the full annual cycle. We are also leveraging state-of-the-art statistical tools which allow us to understand where in the annual cycle bird decisions contribute most to variation in the subpopulation patterns between eastern Canada and the northeastern US. There are few examples of these approaches across animal ecology, so we’re excited about this project’s scope and broad applicability to further research. 

What have you found so far? Any surprises? Major accomplishments?    

No breaking news yet but, over the past three field seasons, we have deployed 974 transmitters and 887 geolocators so there’ll be plenty of data that we can learn from. We are deploying the last round of transmitters and geolocators during Jan-Mar 2025, then three graduate students will lead analyses with these data. Although data will continue to be collected for several years, we anticipate initial results will be available in late 2025. 

What are the next short- and long-term steps for your research project? What questions remain or what new questions have been raised by what you have found so far?  

Our short-term goal is to deploy another round of GPS-acceleration tracking devices and geolocators the first quarter of 2025. Another goal is to ensure the three graduate students on the project are combining tracking device data alongside land use and weather information to test hypotheses and predict relationships. Our long-term steps are to uncover the factors contributing most to differences in the eastern mallard subpopulation trajectories among birds nesting in eastern Canada versus the northeastern US. Because the students have not yet formalized analyses, there are some exciting days ahead when they summarize the data and show the relationships among ~1,200 female mallards throughout the Atlantic Flyway.  

Graduate students Daria Sparks and Cassidy Waldrep attach a GPS-ACC transmitter using the backpack harness technique to a female mallard in New York. Photo courtesy of Josh Stiller.

Why is your study species particularly interesting?   

Eastern mallards are one of the most common and sought after game birds in the Atlantic Flyway. Hunters pursue these birds and the state, provincial, and federal migratory bird agencies have a responsibility to wisely manage the species. There is interest from a conservation and management perspective about why the two subpopulations have different trajectories and how we might develop appropriate management strategies. More ecologically, mallards are a generalist and one of the most flexible migratory birds in the world. They occur throughout the Atlantic Flyway in urban and rural landscapes, from the boreal forest of Canada to the rice fields of South Carolina. Their flexibility makes them an interesting species to study because they encounter substantial changes in land use and weather patterns throughout the annual cycle. We can learn about the potential for other species to adapt based on these patterns in mallards. 

Who is involved in your project (individuals, university, partners, collaborators)?  

Our core research team is made up of multiple Principal Investigators and three graduate students, including:  

  • Dr. Mitch Weegman: Ducks Unlimited Endowed Chair of Canada, University of Saskatchewan 
  • Dr. Jacob Straub: Senior Research Associate, State University of New York-Brockport 
  • Josh Stiller: Small Game Unit Leader, New York Department of Environmental Conservation 
  • Dr. John Coluccy: Director of Conservation Planning & Science, Ducks Unlimited Inc.  
  • Nate Huck: Previous PA Game Commission Waterfowl Biologist, now with Minnesota Department of Natural Resources 
  • Amanda Hoyt: Waterfowl Biologist, PA Game Commission 
  • Cassidy Waldrep (MSc roll up to PhD student at the University of Saskatchewan) 
  • Daria Sparks (MSc student at SUNY-Brockport) 
  • Abigail Butler (MSc student at SUNY-Brockport) 

We also work with an extensive network of biologists representing 14 US states and 3 Canadian provinces (along with U.S. Fish and Wildlife and Environment and Climate Change Canada) that lead field efforts to ensure transmitter and geolocator deployment. These biologists and technicians also help recover units throughout the year.  

  • New York State Department of Environmental Conservation led by Josh Stiller 
  • Pennsylvania Game Commission à led by Amanda Hoy 
  • Delaware Department of Natural Resources and Environmental Control à led by Adam Macy 
  • Environment and Climate Change Canada, including: Ted Barney à Atlantic Provinces, Mathieu Tetreault à Quebec, and Shawn Meyer à Ontario 
  • Maine Department of Inland Fisheries and Wildlife à led by Kelsey Sullivan 
  • Maryland Department of Natural Resources à led by Josh Homyack and Kayla Harvey 
  • Massachusetts Division of Fisheries and Wildlife à led by H Heusmann 
  • State of New Hampshire Fish and Game à led by Jessica Carloni 
  • New Jersey Division of Fish and Wildlife à led previously by Ted Nichols (retired), currently led by Austin Damminger
  • North Carolina Wildlife Resources Commission à led by Doug Howell 
  • Rhode Island Department of Environmental Management à led by Jennifer Kilburn 
  • South Carolina Department of Natural Resources à led by Molly Kneece 
  • U.S. Fish & Wildlife Service à led by Patrick Devers and Tony Roberts 
  • Vermont Fish and Wildlife à led by Andrew Bouton 
  • Virginia Department of Wildlife Resources à led by Ben Lewis 
  • West Virginia Division of Natural Resources à led by Michael Peters 
     

How has bird banding/marking changed over the course of your career or during this project?  

Over the past two decades, there has been great advancement of auxiliary markers. When John Coluccy first started, almost forty years ago, VHF telemetry was used for tracking and geolocators were not yet available. Then PIT-tags started becoming available, and shortly after that, GPS-ACC transmitters were developed. The advancement of GPS-ACC units has created a way in which biologists can link location with behavior. Geolocators, developed more recently, then provide a way for a “control,” as it attaches to the leg of the bird and weighs very little.  

Graduate student Abigail Butler holds a female mallard while waiting for glue to dry. Photo courtesy of Josh Stiller.

Why do you think projects like yours are so important?   

Large-scale collaborative projects are important because they address a variety of science needs from the conservation community. Our group spans state, provincial and federal researchers, as well as those from conservation organizations and universities. There are substantial strengths realized by combining expertise for common goals, such as uncovering movements, behavior, survival and reproductive success in eastern mallards throughout the Atlantic Flyway. While each tracking device is relatively expensive ($1000 USD), the costs can be shared among partners. By allowing for greater sample sizes (~1200 GPS-acceleration units in this case), the data from this project should be representative of the eastern mallard population and meaningful for answering our project questions. In general, projects that test hypotheses at the individual level, like ours, can be very important because they provide data about fine-scale decision-making from these birds that is otherwise impossible to collect we can’t follow the same individual throughout the full annual cycle, and among years, in any other way. Therefore, these data are unique and at a large scale, enabling us to address a pressing conservation problem. These research questions also provide immense training opportunities for graduate students, who will become future conservation leaders. That blend is exciting.  

Where can I get more information about your project (project website, publications etc.)?   

The Eastern Mallard Project can be followed via this website https://atlantic-flyway-waterfowl-gps.weebly.com/. You’ll also see information about American black ducks. There is a related project led by Ilsa Griebel, a PhD student supervised by Dr. Mitch Weegman at the University of Saskatchewan. Ilsa and many of the same agency partners are deploying ~850 GPS-acceleration tracking devices on black ducks in the Atlantic Flyway to quantify drivers of reproductive success in the eastern boreal forest. Data from eastern mallards and black ducks will also be used jointly for more robust inference about how the species interact throughout the annual cycle. None of the graduate students have formalized analyses for this work yet, so we do not have papers about these projects. We anticipate a group of papers on these projects to be published from 2025 onward.  

Is there anything else you think is important to mention about your project/research?   

We would like to thank our project partners for their support of this work. The Eastern Mallard Project is a massive endeavor, only possible through flyway-scale support from hundreds of people contributing critical thinking, finances and logistical support via personnel to catch birds. This is a team effort, and we really appreciate it. 


The “Notes From the Field” series highlights current banding projects and the continued importance of bird banding and the Bird Banding Lab. Want to see your project featured in a future “Notes From the Field” article? Email Kyra Harvey kharvey@usgs.gov for submission details. 

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 

This United States Geological Survey news article "Notes from the Field: Eastern Mallard Project" was originally found on https://www.usgs.gov/news

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