Applications of an unmanned aerial vehicle and thermal‐imaging camera to study ducks nesting over water

Abstract

Finding and monitoring nests are key components of avian research, but they are often expensive, time-consuming, and inefficient operations. This is certainly true for diving ducks that nest in wetlands with thick emergent vegetation where nests are typically located by teams of technicians that wade through a marsh and beat vegetation with sticks, hoping to flush incubating females or encounter nests without a female present. Taking advantage of recent advances in both unmanned aerial vehicles (UAVs) and thermal-imaging cameras, our objectives were to (1) compare our ability to locate duck nests using a UAV and using traditional on-foot searching methods, and (2) determine if nests monitored remotely with the UAV had different survival rates than nests monitored with traditional nest-site visits. We searched for nests with a UAV system in southern Manitoba during the springs of 2018 and 2019. Using the UAV, we located 48 nests not found by ground crews, ground crews found 164 nests not found with the UAV, and 71 nests were found using both methods. Overall, nests were less likely to be detected with the UAV (0.34) than by ground crews (0.71), but surveys were completed approximately four times faster with the UAV. Detectability of nests varied among duck species (range = 0.55-0.04). We found no difference in nest survival between nests monitored with the UAV (0.95) and those repeatedly visited by ground crews (0.95). However, in 2018, ground monitoring resulted in 19 nests being abandoned by females, compared to only one monitored with the UAV. Our results demonstrate that UAVs equipped with thermal cameras can be used to find nests of ducks located over water, with greater success for species that nest earlier and those whose nests are not buried under matted vegetation. Furthermore, monitoring nests with the UAV resulted in lower rates of nest abandonment, and survival of nests monitored with the UAV was similar to that of nests monitored using traditional methods. Additional species-and habitat-specific studies are needed to fully understand the utility and challenges associated with using UAVs equipped with thermal imaging to survey species of wetland wildlife.

Using UAV‐mounted thermal cameras to detect the presence of nesting nightjar in upland clear‐fell: A case study in South Wales, UK

“…radio tags: Alexander & Cresswell, 1990; thermal imagery: Boonstra et al., 1995; Boulton & Cassey, 2012; Galligan et al., 2003; McCafferty et al., 1998; and recently the use of unmanned aerial vehicles [UAVs]). UAV‐mounted thermal sensors can monitor the heat radiation of visually cryptic endothermic animals to identify their location (Bushaw et al., 2020; Israel & Reinhard, 2017; Santangeli et al., 2020; Seymour et al., 2017; Witczuk et al., 2017; ). UAVs can provide a means of rapidly surveying large areas using thermal sensors and may represent a more cost‐effective less disturbing alternative to traditional research methods (Bushaw et al., 2020; Christie et al., 2016; Santangeli et al., 2020).…”

Application of Unmanned Aerial Vehicles and Thermal Imaging Cameras to Conduct Duck Brood Surveys

“…For example, Bushaw et al (2019) used a quadcopter UAV equipped with a thermal camera to locate and identify nocturnal mesocarnivores in southern Canada and reported being able to detect animals as small as rodents in grassy fields. Scholten et al (2019) used a UAV and thermal camera to locate small, well‐hidden field sparrow ( Spizella pusilla ) nests in grasslands in the northern United States, and Bushaw et al (2020) used a similar system to locate diving duck nests in prairie Canada. Here, we evaluated whether UAVs equipped with thermal imaging cameras could be used to locate duck broods.…”

Nesting Common Eiders (Somateria mollissima) show little behavioral response to fixed-wing drone surveys

“…Eiders generally take recess events outside of daylight hours to minimize nest loss from ubiquitous avian predators who are inactive at night (Swennen et al 1993;Bolduc and Guillemette 2003b;Stechmann 2019). Our findings suggest the best time to survey when the female eider is on the nest is during the day, but if thermal sensors that use relative temperatures are used for detection, the most ideal survey times are typically at night or early mornings when the temperature contrast is greatest between the background and the nest (Bushaw et al 2020;Helvey et al 2020).…”

“…However, rotary wing platforms provide flexibility for different kinds of sensors and applications. This may include thermal, multi-spectral, or hyperspectral sensors to enhance detections of cryptic-colored birds from the surrounding landscape (Scholten et al 2019;Bushaw et al 2020;Helvey 2020;Helvey et al 2020). One major consideration with the use of these sensors is the altitude at which they were flown.…”