RESEARCH AND EDUCATION 2021 STATUS UPDATE

Studying the seasonal and annual “movement ecology of ring-necked ducks in the southern Delta furthers the research Atlantic Flyway helped that keeps waterfowl grow my passion for

research and pushed ™ populations strong me to continue my Using the latest technology, researchers education to obtain answer tough questions about duck a Ph.D. Tori Mezebish production and wetland conservation UNIVERSITY OF today and in the future RHODE ISLAND 2025 PH.D. BIOLOGICAL” AND ENVIRONMENTAL SCIENCES Delta Waterfowl believes that water- It’s a philosophy Delta has followed fowl management decisions should since Albert Hochbaum began his always be based on sound science. work as the organization’s first science 2021 research program. The summaries director in 1938 at the Delta Marsh. that follow provide a snapshot of each Delta has continually focused research project, and more detailed information is DELTA HAS TRAINED MORE on ducks and duck hunting issues in available. As always, feel free to contact THAN 600 MASTER’S AND North America. This strategy allows me to discuss any of Delta’s research. DOCTORAL STUDENTS, The Duck Hunters Organization to INCLUDING SOME OF TODAY’S study important, long-term issues, as Dr. Chris Nicolai FOREMOST WATERFOWL well as new concerns impacting ducks Waterfowl Scientist BIOLOGISTS and duck hunters. (775) 830-1632

[email protected] THE DUCK HUNTERS ORGANIZATION This special report highlights our

1 Canvasback Nest Success cameras, since this approach has proven “hot spots” (i.e., grass-only sites) would Evaluating Predator Management for over-water nesting ducks far superior to field assistants doing allow waterfowl managers needed ground counts. Rohrer will be finishing flexibility in both the size and loca- TRENT ROHRER, M.S. STUDENT, AND DR. JOSH STAFFORD, his M.S. work this year. tion of Predator Management sites. SOUTH DAKOTA STATE UNIVERSITY This project will take place in North Hot Spot Trapping to Dakota and help inform whether “hot Delta continues to seek effective and Improve Dabbler Production spot” trapping can help increase duck Evaluating dabbler nest success efficient application of Predator Man- with a new trapping technique production in the best quality habitats. agement techniques to improve nest To estimate how many ducks are MATT DAVIS, M.S. STUDENT, AND success for over-water nesting ducks DR. CHRISTOPHER MALCOM, using the different treatment blocks, such as canvasbacks, redheads and BRANDON UNIVERSITY we are using a variety of methods to ring-necked ducks in the parkland estimate how many nests are missed habitat of Canada. Delta is exploring whether focusing using a single pass chain drag. Efforts Rohrer has spent the past two years Predator Management on highly pro- to use GPS to map ATV tracks and exploring whether trapping in the fall, ductive patches of grassland habitats nests will allow the use of distance in addition to the spring, is a more could more efficiently boost produc- sampling methods. We are also effective way to reduce key mammalian tion of dabblers such as mallards, dragging a sample of nesting cover nest predators, especially raccoons. pintails and gadwalls. This project a second time within 20 minutes to We discovered fall trapping did little is vastly different from past nesting/ determine how many nests are missed to improve our take of raccoons – predator removal projects in that we on a single pass. public enemy No. 1 of canvasbacks. are interested in assessing how many However, our spring trapping in 2020 ducks are attempting to nest, rather Raccoon Satellite Telemetry Studying movements and habitat use showed some very positive signs, than simply measuring nest success. of raccoons to improve effectiveness so we intensified that effort for the Predator trapping has typically of Predator Management second field season. That includes focused on the full area of a town- DR. CHARLOTTE MILLING, trapping out in wetland edges where ship-sized block. Recent Delta research POST-DOCTORAL RESEARCHER, DR. STANLEY GEHRT AND our satellite tracking of coons showed projects have identified “hot spot” MR. SHANE MCKENZIE, MAX these introduced predators spend an trapping as a potentially more effective MCGRAW WILDLIFE FOUNDATION inordinate amount of their time. We approach to removing predators and will be counting broods using drones a more efficient use of management In 2018 and 2019, we fitted 29 rac- equipped with thermal and visual dollars. Focusing trapping efforts on coons with GPS transmitting collars on Delta’s canvasback study block in Manitoba. The transmitters collected ™ incredible amounts of location data on each raccoon’s daily movements. We discovered that raccoons spent a large percentage of time in wetland edges. Due to Covid-19, we were unable to track any raccoons in 2020. However, we are planning to collar 15 raccoons to track their movements in breeding duck habitat. The goal is to better understand raccoon habits so we can set traps in their preferred locations, thereby more effectively reducing these top predators of diving-duck nests. We will also use stable isotopes to evaluate the role of duck eggs in the diet of raccoons. Ultimately, the goal is to learn more about raccoons so we can manage these non-native predators and increase production of canvasbacks, redheads, ring-necked ducks and other THE DUCK HUNTERS ORGANIZATION over-water nesting ducks.

2 This experience has greatly helped my career. I’ve had the “ opportunity to meet many researchers, hunters, and landowners and share with them why we’re doing this research. After graduation, I’ll be starting a position as a research scientist, due in large part to the experience I gained doing research for my master’s degree with Delta Waterfowl. Catrina Terry LOUISIANA STATE UNIVERSITY 2021 MASTER OF SCIENCE ” ™ THE DUCK HUNTERS ORGANIZATION

3 harvest — the only diver consistently in the top 10 in all four flyways. Ringnecks are doing well, and we hope to understand why they have been so successful at increasing in numbers. In addition, this research has immediate value to waterfowl managers in the Atlantic Flyway under the recently implemented multi-stock harvest regulation-setting method. Importantly, our study suggests that ring-necked ducks that winter in the southeast are not nesting in the eastern survey area, but farther west. Eastern Mallard banding and isotopes Using isotopes to determine whether mallards are moving between the US and Canada during banding operations KAYLA HARVEY, M.S. STUDENT, AND DR. MIKE SCHUMMER, STATE UNIVERSITY OF NEW YORK COLLEGE OF ENVIRONMENTAL SCIENCE AND FORESTRY

Counting Broods Ring-necked Duck Tracking Implanting satellite transmitters to Using Drones Mallards in the Atlantic flyway have Evaluating brood use of wetlands in monitor movements and habitat use agricultural landscapes declined by 40 percent in recent years, DR. MITCH WEEGMAN, and reasons for this decline are not well CATRINA TERRY, M.S. STUDENT, AND UNIVERSITY OF MISSOURI DR. KEVIN RINGELMAN, LOUISIANA understood. Banding data, specifically STATE UNIVERSITY pre-hunting season banding, is an After three successful field seasons important tool used to monitor mal- In 2019, we surveyed 242 PPR wet- marking ring-necked ducks in 2018, lard and other waterfowl populations. ™ lands using a combination of cam- 2019 and 2020, Delta implanted an Production and survival estimates for era-equipped drones and wetland additional 31 ringnecks with satellite Atlantic flyway mallards, informed sampling and found 240 broods. In transmitters in Maryland during the by banding data, have not changed 2020, 92 wetlands were sampled to fourth and final field season of the significantly during the decline, sug- find 88 broods. project in February 2021. gesting a possible bias in these data. Using a special drone equipped The goals are to monitor migration An important assumption used for with a thermal-imaging camera and paths, discover breeding areas, and these estimates is that birds do not move a regular camera, researchers survey understand habitat use and movements between survey units. Recent research selected wetlands in agricultural land- suggests the potential for migration of scapes for brood use. The goal is to mallards during the banding period. better understand brood use in order DELTA WATERFOWL’S This project aims to use stable isotope to conserve the most important habitat RESEARCH AND EDUCATION analysis to determine whether mallards for breeding ducks. This research will PROGRAM HAS RESULTED are moving during the banding peri- evaluate the quality of wetlands as brood IN MORE THAN 950 PEER- od. Feather samples from pre-season water by examining usage by ducks, REVIEWED STUDIES banded birds throughout the Atlantic as well as determining invertebrate flyway will be collected for analysis abundance, vegetation structure and of the deuterium isotope to obtain insecticide concentration. during the ringneck’s annual cycle. Little general molt or natal origins. These Terry has finished this field work is known about ring-necked ducks, will then be compared to banding and expects to complete her M.S. which is surprising because they are the locations to assess movement during THE DUCK HUNTERS ORGANIZATION this year. most important diving duck in hunter the banding period.

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While working as a Delta researcher, I have been able to connect and network with a wide variety of people in the hunting, research, and agricultural communities. I learned “that conservation issues are complex and challenging, nothing happens overnight, and working hard to connect with people helps to build the necessary relationships that push conservation forward. Michael Johnson, COLORADO STATE UNIVERSITY 2023 PH.D., FISHERIES, WILDLIFE AND CONSERVATION BIOLOGY ” THE DUCK HUNTERS ORGANIZATION

5 Lower Mississippi Working Wetlands influence does hunting harvest have Understanding farmers’ perceptions Flyway Dabbler Tracking on populations? Determining duck locations during of Delta’s Working Wetlands program By using new scientific approaches, hunting seasons and migration DR. CHERYL WACHENHEIM, NORTH DAKOTA STATE UNIVERSITY the team can more accurately answer DANIEL ODIN, M.S. STUDENT, STARLA PHELPS, M.S. STUDENT, DR. this question for a number of important DOUGLAS OSBORNE, UNIVERSITY OF ARKANSAS DIVISION OF species, including mallards, pintails AGRICULTURE, AND DR. MITCH Delta Waterfowl, in partnership with and blue-winged teal. They will take a WEEGMAN, UNIVERSITY OF MISSOURI the U.S. Department of Agricul- unique approach and look at population ture Natural Resources Conservation cohorts (male/female and juvenile/ Service, initiated a new approach to adult) to more fully understand how Delta Waterfowl seeks to better un- conserving small wetlands in crop- differing survival rates might help in- derstand the migration and wintering land. This research involves human form the relationship between harvest ground habits of dabbling ducks in dimensions survey work of program and population sizes. In addition, they the Mississippi Flyway to determine participants so that we can learn from will revisit our understanding of how ™ whether further management strategies producers and thereby determine how density dependence (i.e., how many are needed. we can better serve farm operations and breeding pairs of ducks that a given Employing backpack transmitters protect small wetlands that are critical year’s wetlands can accommodate) powered by miniature solar panels, for breeding ducks. The research will works in duck populations. They are Delta installed radios on mallards, inform large, landscape-scale program finding that long-used models may green-winged teal and American wigeon development pioneered by Delta’s not improve our understanding of to record movements for the past two Working Wetlands and incorporated the impacts of hunter harvest on duck years. Ducks were caught during or in the 2018 Farm Bill, in hopes of populations. after the 2019-2020 and 2020-2021 conserving wetlands across the U.S. hunting seasons in Arkansas. Prairie Pothole Region. Spatiotemporal Variation The primary goal is to understand in Duck Demographic Rates How environmental change when and where these ducks migrate, Pintail Harvest and Survival How does hunting harvest impact influences duck population dynamics particularly in the fall, as well as how duck populations? MADELEINE LOHMAN, PH.D. they respond to hunting pressure and STUDENT, AND DR. PERRY THOMAS RIECKE, POST-DOCTORAL WILLIAMS, UNIVERSITY OF NEVADA weather events. Odin is focusing on RESEARCHER, UNIVERSITY OF RENO describing preferred habitats each NEVADA RENO species choose to use during the winter. Phelps is assessing fine-scale Waterfowl monitoring efforts have cre- movements of these radios during Researchers are undertaking one ated one of the few extensive multi-spe- their time spent in the Mississippi of the big unanswered questions cies, longitudinal, individual-based data THE DUCK HUNTERS ORGANIZATION Alluvial Valley. in waterfowl management: What sets in the world. Using these data,

6 Lohman will investigate spatiotem- Additionally, examining long-term Banding data currently estimates that poral variation in demographic rates pintail data has become more import- about two-thirds of mallards shot in of dabbling ducks in the PPR to help ant, as data sets continue to grow and the eastern U.S. stem from the eastern shed new light on basic biology and analytical techniques expand to make U.S. breeding population. We are conservation needs of widely distributed sense of long-term changes. finding that the banding data does wildlife populations. not account for movement of birds This work will focus on variation in Atlantic Flyway from Canada prior to the banding mallard demographic rates, correlations Mallard Stable Isotope period and that a larger proportion Determining the origins of mallards between mallard survival and age taken by hunters in the east than expected of Canada derived ratios, and spatiotemporal variation birds are being banded in the U.S. SAM KUCIA, M.S. STUDENT AND in natural and harvest mortality. We DR. MIKE SCHUMMER, STATE Eastern mallard ecology and harvest UNIVERSITY OF NEW YORK COLLEGE will then use these methods to compare OF ENVIRONMENTAL SCIENCE AND management have taken a back seat multi-species demographic rates. FORESTRY relative to other flyways, but we aim to reverse this information deficit and ™ Has Pintail deliver quality information that can Production Declined? Delta is undertaking this important help better manage eastern mallards. Evaluating changes in pintail age structure and sex ratios research to inform mallard harvest Kucia is completing his analyses regulations in the Atlantic Flyway. and writing his thesis and plans to DR. TODD ARNOLD, UNIVERSITY OF MINNESOTA Spring surveys suggest that the graduate this year. eastern U.S. mallard population is declining, while eastern Canada’s Canvasback/Redhead Pintail population trends are of great mallards are holding stable. Therefore Integrated Population Models Determining needs for management interest to duck hunters, especially in we need to understand the relative of key diver species light of U.S. Fish and Wildlife Service importance of the different breeding DR. DAN GIBSON, POST-DOCTORAL regulations lowering the bag limit to areas, particularly given the reduction RESEARCHER AND DR. DAVID KOONS, COLORADO STATE one bird per day in 2017-2018, and of Atlantic Flyway mallard limits to UNIVERSITY again for the 2019-2020 and 2020-2021 two mallards (one hen) daily for the seasons. Dr. Arnold is reviewing pintail 2019-2020 and 2020-2021 seasons. age and sex ratios using USFWS Parts By examining stable isotopes in Redheads and canvasbacks use the Collection Survey data to document the flight feathers of mallards shot same breeding habitat in the PPR how age ratios (proportion of juveniles in the Atlantic Flyway, researchers (primarily Manitoba and Saskatchewan), in the fall flight) and sex ratios (females can determine where the ducks grew and Delta has collected extensive data to males) have changed since 1961. This those feathers in the summer. This is on pairs, nests and broods for both work is important to inform the pintail a novel way to determine the origins species. By using multiple data sets harvest models used to set regulations. of birds shot in the Atlantic Flyway. simultaneously, we can learn more THE DUCK HUNTERS ORGANIZATION

7 about what drives their populations. data to gain understanding of the The goal of this data analysis work trade-offs these ducks are making to is to develop a model of the annual life maintain a stable population. cycles for canvasbacks and redheads to determine what factors drive their Large Scale Pacific population growth. The resulting Flyway Radio Project Monitoring movements of geese and models will characterize the importance ducks in the Pacific Flyway of nest success, survival of nesting DR. CHRIS NICOLAI, DELTA hens, brood survival, winter survival WATERFOWL, MIKE CASAZZA, USGS, DELTA WATERFOWL’S LEGACY CLIFF FELDHEIM, CA DEPARTMENT and hunting mortality on population OF LEADING-EDGE SCIENCE OF WATER RESOURCES, MARK growth of redheads and canvasbacks. PETRIE, DUCKS UNLIMITED, AND DATES TO THE 1930S, WHEN CAROLINE BRADY, CALIFORNIA The results from this study will benefit ALDO LEOPOLD VISITED WATERFOWL ASSOCIATION management efforts and help drive MANITOBA’S DELTA MARSH. future research efforts on these species. This is the largest scale satellite telemetry Canvasback Habitat Modeling wood ducks. Importantly, she found project ever undertaken, having marked Analyzing nest success in relation to habitat variables mercury levels as high as 40,000 ppb more than 800 ducks and geese of 14 spe- and found a correlation between tissue cies in the past six years. To do so requires MICHAEL JOHNSON, PH.D. CANDIDATE AND DR. DAVID KOONS, and feather samples. She will compare numerous partners to assist with fitting COLORADO STATE UNIVERSITY mother and offspring levels of mercury birds with radios, maintaining massive data to determine whether offspring directly, sets, and analyzing and writing papers. or indirectly inherit mercury loadings. The three primary objectives are to assess After several seasons of extensive The levels of mercury found in this the full annual cycle of habitat use; how field work on nesting canvasbacks in population of wood ducks is among the different populations of the same species Manitoba, Johnson will analyze habitat highest levels ever recorded in a bird are delineated; and how overpopulations variables to determine their impact on species, exceeding levels for survival of some geese impact the limited food nest abundance, nest success, and brood and reproduction. We will use this resources of ducks. counts. The goal is to determine the best locations on the prairie breeding grounds for canvasback production. Research Leaders This information will help waterfowl Throughout the organization’s storied history, Delta Waterfowl has managers target where to best invest amassed an impressive body of research that includes supporting in wetland conservation programs to more than 300 graduate students and publishing more than 950 peer- ™ benefit canvasback production. reviewed scientific papers. Delta’s research has profoundly influenced how waterfowl, wetlands and Mercury Loading in annual harvest are managed. It has also provided biologists, technicians Nevada Wood Ducks and young scientists with the opportunity to gain hands-on experience Demographics of a wood duck population in a mercury superfund site and guidance to become leaders in waterfowl and wetland conserva- tion. We are proud that many of Delta’s former students are working MORGAN BYRNE, M.S. STUDENT, DR. PERRY WILLIAMS, DR. MAE GUSTIN, for government and non-government agencies, as well as universities. UNIVERSITY OF NEVADA RENO, AND DR. CHRIS NICOLAI, DELTA Delta Waterfowl’s important waterfowl and wetland research is made WATERFOWL possible by you — our generous donors, members and volunteers. We deeply appreciate your support. Thank you!

Delta’s Dr. Chris Nicolai has main- tained an 18-year project monitoring DELTAWATERFOWL.ORG an isolated population of wood ducks in western Nevada. During the life of U.S. Office Canada Office this project, feather samples have been 1412 Basin Avenue 200-1765 Sargent Avenue collected from all banded birds and Bismarck, ND 58504 Winnipeg, MB R3H 0C6 repeated feather sampling occurred OFFICE 701.222.8857 OFFICE 204.956.7766 for all nesting hens. Byrne collected TOLL FREE 1.888.987.3695 TOLL FREE 1.877.667.5656 [email protected] [email protected] liver, breast tissue and two types of THE DUCK HUNTERS ORGANIZATION feather samples from 100 hunter-killed

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