Eyes in the Sky: DU Using Aerial Drones to Expand Waterfowl Understanding

by Jennifer Boudart

Unoccupied aerial vehicles, or drones, have many unique capabilities that are proving highly useful to Ducks Unlimited. In fact, drone technology has become an important tool for DU’s wetland and waterfowl research, its project design and delivery, and its communications and marketing efforts. While DU usually contracts with university researchers, federal agencies, or private industry partners for the use of drone technology, several of its offices now have their own drones. And a growing number of DU staff are becoming FAA-licensed drone pilots.

One of them is Chris Sebastian, sustainability lead and external affairs manager for DU’s Great Lakes/Atlantic Region. When it comes to the value of drone technology as a communications tool, says Sebastian, “the old cliché that ‘a picture is worth a thousand words’ really is true. And a video is worth even more.” He says drone imagery offers a uniquely effective way to educate current and potential supporters about the impact of DU’s work. “We realize one of the best ways for us to tell our story is to show our projects from a duck’s-eye point of view. Drones allow us to do that.”

Sebastian used a drone to help develop an interactive map of DU projects in the Great Lakes/Atlantic Region. Over the course of two years, he and various DU biologists visited nearly 70 projects in 21 states, putting the drone up at each stop. The footage was edited to create videos narrated by DU biologists, and all the videos are posted on the DU website at ducks.org/FlyDU. Sebastian says this tool has received fantastic feedback. “People are excited to take a tour of what’s in their backyards from an angle they haven’t seen before.”

DU engineers have also been using drones to aid with project planning and delivery. Among them is William Cenac II, PE, a regional engineer in DU’s South Louisiana field office who is a licensed drone pilot. Cenac says one value that drones provide is the ability to generate the most up-to-date imagery to share with contractors during the project bidding process. That’s not always possible when relying on satellite imagery from a geobrowser.

Photo © GARYKRAMER.NET

Cenac also finds drones useful for construction planning and management, especially for projects covering large areas of marsh where access can be challenging. The aerial view from a drone can reveal features and obstacles, such as old canals or crevasses or areas of deep or shallow water, that may impact construction. Engineers may also use drone photography to create before-and-after views of a given project, and in certain cases to help monitor a project after completion.

Drones also offer several benefits for waterfowl research, particularly waterfowl surveys. Using drones is safer than flying aerial surveys from a helicopter or fixed-wing aircraft. It also generally increases accuracy in terms of finding, counting, and identifying birds, and it often cuts down on costs and time while providing access to areas that may be difficult to survey by other means. The information that drones record is also easier to share. 

DU just wrapped up a four-year research project in the Prairie Pothole Region that involved using drones to conduct brood surveys. The project’s focus was brood presence and abundance on wetlands located in intensively farmed land in Minnesota, Iowa, and North and South Dakota. Project partners included Iowa State University, Louisiana State University (LSU), Delta Waterfowl, and the US Geological Survey Northern Prairie Wildlife Research Center. Work was conducted by two graduate students. Blake Mitchell, from Iowa State University, researched brood presence using a drone provided by DU. Catrina Terry, from LSU, researched brood abundance using a drone provided by Delta Waterfowl.

Both drones were equipped with thermal and optical cameras to detect the broods. They proved surprisingly effective at this task, mainly because ducklings show up as bright white objects on the thermal camera. “The color of objects detected by a thermal camera is determined by the amount of heat they reflect into the atmosphere,” Mitchell explains. “The ducklings reflect a lot more heat because they lack a complete set of feathers to trap it in.” Ducklings light up like little flashlights, even when hiding in vegetation. (The well-insulated hens tend to appear gray.) Mitchell and Terry were able to count the ducklings, identify their species, and determine their age. In the end, the combination of thermal and optical cameras on the drones nearly doubled the detection probability on average. Both Mitchell and Terry now work for DU, and Terry says she continues to be involved with using drones for other brood survey work in North Dakota.

Photo © Ryan Martin, DU

In the Mississippi Alluvial Valley, DU is testing drones to monitor duck use within forested and shallow-water habitats on Wetland Reserve Easement sites. There’s a need to better understand how waterfowl respond to management activities on these sites, but dense bottomland hardwood forests make monitoring difficult. DU is partnering on the project with the National Fish and Wildlife Foundation and LSU. Zack Loken, an LSU graduate student, recently finished the first season of field work.

Loken deployed a drone at 14 study sites in Arkansas, Louisiana, and Mississippi. He used thermal video footage to locate ducks and count them. He also cross-referenced the videos with optical imagery to identify their species (mostly focusing on drakes). Loken is using the data to train a machine-learning model and to develop a stand-alone computer program. He has used it to differentiate between species of ducks with just over 90 percent accuracy. Loken has also been able to assign a general habitat use behavior for each duck identified—foraging, if the duck is in motion, and loafing if it’s motionless. Loken’s work could ultimately allow biologists to import their own drone footage and derive duck counts, species identification, and general use behaviors.

Drones can also be used to monitor landscape-related changes, such as land-to-water ratios and vegetation growth. For example, drones were recently tested as a method for detecting the presence of submerged aquatic vegetation (SAV) in a study to determine possible differences in the amount of SAV in terraced versus unterraced sites along the Gulf Coast. The objective was to determine if drone photography could successfully detect SAV growing at the water’s surface (an alternative to the traditional method of dropping a rake into the water column and pulling it up to see if SAV is present). Nearly two dozen sites were surveyed, including both terraced and unterraced sites. Photo analysis revealed that the drone cameras did detect where SAV was present with relatively high accuracy, making it a potentially promising tool for this purpose.

These are just a few examples of how DU is applying drone technology in unique ways to support its conservation mission—and how drone imagery is creating powerful new perspectives of DU’s work.

Drone Effects on Duck Behavior

Wildlife disturbance can be a concern when using drones. DU partnered with the University of North Dakota to research best practices for minimizing disturbance when using drones to survey breeding pairs and nesting hens.

The research involved flying a drone over a given wetland while researchers simultaneously recorded waterfowl responses from the ground. Observers also studied waterfowl behavior at a control wetland where no drone was used. Results indicated that ducks were aware of the drone’s presence but that most ducks did not flush, and any behaviors related to the drone were only temporary. Ducks resumed preflight activities after the drone survey was completed. Similarly, nesting hens noticed the aircraft but appeared more sensitive to the quadcopter drone than the fixed-wing