Precision Counting of Sandhill Cranes in Staten Island by FAA Approved Small Unmanned Aerial System Night Missions

Abstract

One important challenge for Sandhill Crane conservation is the collection of regular, accurate counts of birds roosting in flooded areas at night. Estimates of roost site numbers are an important way to track population size over time and detect any changes in site selection that may be a function of management or changes in site conditions. Traditional methods for estimating roosting crane numbers are morning and evening counts of cranes as they arrive at or depart their roosting sites. The accuracy of these counts however is often hampered by poor visibility in foggy and/or low light conditions, variations between observers, difficulties in accurately estimating the number of birds when many are flying to or away from the site, and difficulties in pinpointing specific locations where birds are roosting. Use of small unmanned aerial systems (sUAS) equipped with infrared cameras provide a promising alternative for developing more accurate estimates of roosting population numbers efficiently and more frequently, as well as a method of mapping specific roosting locations relative to habitat features. sUAS could also assist in surveying new areas for roosting cranes, as even though these birds are often traditional, they are known to colonize new areas if habitat conditions are suitable. This paper presents a case study on how to get approval from the Federal Aviation Administration (FAA) for night flight missions, how to decide the mission parameters and timing, as well as initial post-processing workflows. From 11 night missions performed, we also will share in this paper our findings and lessons learned.

Drones as a tool to study and monitor endangered Grey Crowned Cranes (Balearica regulorum): Behavioural responses and recommended guidelines

“…Guidelines for using drones to study animals usually suggest that small drone sizes (<2 kg), implementing further take‐off distances from the subject/s, higher flight heights, slow speeds and horizontal rather than vertical approaches can reduce the disturbance imposed on birds, but these responses can vary between species (Barr et al., 2020 ; Duporge et al., 2021 ; Lyons et al., 2018 ; Marchowski, 2021 ; Sorrell et al., 2023 ; Vas et al., 2015 ; Weimerskirch et al., 2018 ; Wilson et al., 2021 ). Drone use in crane research and monitoring is in its infancy, with studies generally using drones to estimate population densities (e.g., Sandhill Cranes Grus canadensis (Stark et al., 2017 ), Siberian Cranes Leucogeranus leucogeranus (Wen et al., 2021 ) and Common Cranes ( Grus grus ) (Chen et al., 2023 )). Exploratory work investigating 33 bird species has shown that drones generally impart minimal disturbance when counting populations; however, the responses of Common Cranes towards drones in this study were inconclusive (Marchowski, 2021 ).…”