Article Archives
NDSU Team Studies UAS Role in Blackbird Control

Monday, February 1, 2021
filed under: Birds

        Blackbirds cause millions of dollars in damage to sunflower fields every year. In North Dakota’s Prairie Pothole region, bird damage can exceed the generally accepted industry standard of 5%.  For some sunflower producers, blackbirds can cause total economic losses.
        Current research is showing a unique shift in red-winged blackbird populations. There is an overall population decline across North America, but an increase in breeding populations in North Dakota. This results in a potential increase in conflict, and bad news for sunflower growers.
Mallory White
       But good news could be on the way, in the form of Unmanned Aircraft System (UAS) platforms.  North Dakota State University graduate student Mallory White, in collaboration with USDA Wildlife Services-National Wildlife Research Center, shared an update on her research project, “A Bird’s Eye View: Blackbird Flock Response to Unmanned Aircraft System Approaches in Sunflower Fields” at the 2021 NSA virtual Research Forum in January.
        “We need a dynamic tool to reduce blackbird damage to sunflower as that damage is actively occurring,” White explained.  “Research using UAS, or drones, to haze blackbirds in sunflower fields has been done; but now there needs to be an increased negative stimulus to get blackbirds to stay out of the fields.”
        White outlined preliminary results of her research, which began with a pilot study in 2019 and continued in 2020.  Both years, she said, there were two primary objectives:  (1) establish flight initiation distance (FID) of free-ranging blackbird flocks in commercial sunflower fields and cattails when approached by an UAS, and (2) measure variables that may impact FID in an effort to understand how risky the UAS appears to birds, and to develop methods to apply a bird repellent with a spraying drone.
        White and her team recorded a number of measurements, including field size, flock size, presence of cannons, flock distance from the UAS launch site, flock distance from the edge of the field, as well as vegetation type.  “Our methods were consistent between the two field seasons.  Each trial began with a pre-observation period; in 2019, it was five minutes.  We increased that to 15 minutes in 2020.”
        Two UAS were flown simultaneously. In 2019, the “eye-in-the-sky” UAS flew 60 meters above ground level; in 2020 that was increased to 80 meters.  That “eye-in-the-sky” UAS flew directly above the spraying UAS, which was flying five meters above ground.  The “eye-in-the-sky” recorded the movements of the birds in response to the spraying drone.  “The camera on that UAS was positioned at a 90-degree angle, so it was looking straight down and only recording the movement directly under it,” according to White.
        In 2019, crews conducted 35 trials in the North Dakota counties of Emmons, Kidder, Burleigh, Logan and Kidder.  In 2020, they expanded to 60 trials and added McHenry and Bottineau counties.  Both years, flights were conducted in September and October during daylight hours, and only when sustained winds were less than 17 mph and there was no precipitation.
        The flight initiation distance (FID) was fairly consistent in both years: 38 meters in 2019 and 39 meters in 2020.
        “We found that if the FID is quite large, the flock perceives the UAS as more risky compared to trials with a small FID,” White reported.  “The majority of the flock would flush when the UAS approached.  But, we also discovered that once the UAS left, the birds returned.  Even if we could get birds to leave during 10 minutes of hazing, a large majority returned to that field within 15 minutes.  We know we need to add something besides hazing to keep the birds out.  That’s the direction our study will take this fall.”
        A big takeaway from their research so far, White said, is the use of UAS platforms for precision agricultural and spot treatment of an avian repellent to reduce bird damage to crops.  “In Fall 2021 we will begin testing with a repellent with the active ingredient methyl anthranilate,” White indicated. “We will evaluate how that repellent works in real-time while it’s being actively deployed on areas of the sunflower field where birds are foraging.”
        White is working to further break down data collected in cattails versus sunflower, the effects of extended hazing times on flock behavior, and changes in flock behavior after exposure to UAS hazing.
        White noted that some producers already have drones and are using them to keep blackbirds out of their sunflower fields.  She stressed the importance of getting out to the fields early in the morning.
          “It works best first thing in the morning, when the birds are first arriving into the fields,” she said.  “And when you see blackbirds in a sunflower crop, haze them right away.  Don’t wait until mid-October, right before harvest, to start hazing the birds. Start harassing them early in the season, when they’re less committed to that food source.” — Jody Kerzman

N.D. Growers’ Blackbird Survey Aid Requested
        North Dakota producers can help the NDSU researchers continue their work by responding to a survey being circulated by the team.   A portion of the “2021 Bird Damage to Sunflower Crops: a Survey of Sunflower Producers” will investigate:
        1.  The perception of UAS devices to mitigate blackbird damage
        2.  The willingness of producers to adopt new management techniques
        3.  The factors that influence the perceived efficacy of current management tools
        Surveys were mailed in January.  The team requests past and current North Dakota sunflower producers, regardless of level of bird damage experienced, to reply to the survey. 
        An online version of the blackbird team’s survey can be accessed at the following link: — or, by scanning the QR code below.

      Producers with questions, or who may know of other sunflower producers who may wish to participate, can email either or

return to top of page

   More about Sunflower ►