A new use of technology to solve an old problem: Estimating the population size of a burrow nesting seabird

Abstract

Estimating the population of burrow-nesting seabirds is a challenging task, as human presence in the colony creates disturbances and can damage burrows and occupants. Here, we present a novel method using aerial photographs taken with Unmanned Aerial Vehicles (UAVs) to estimate the population size of a burrow-nesting seabird, the Black-vented Shearwater (Puffinus opisthomelas), on Natividad Island, Mexico. Our results provide a census of burrows in the colony, with very low detection error (5.6%). This is greater accuracy compared to other methods based on extrapolating results from sample plots to total colony area. We then combined this burrow census with ground truth data on occupancy to estimate population size. We obtained a population estimate of 37,858 and 46,322 breeding pairs for 2016 and 2017 respectively. The proposed method provides a cost effective and repeatable approach for monitoring numbers of burrows occupied in a colony, thereby enabling easier and faster estimates of population trends. We suggest this method can be valid for other burrow-nesting species in habitats without dense vegetation cover.

Operational Protocols for the Use of Drones in Marine Animal Research

“…The biggest methodological limitation for monitoring seabirds with drones is typically the ability to effectively distinguish individuals in the imagery, whether this is due to incident angles required for image acquisition [75], camouflaged or hidden nests [83], large numbers and highly mobile individuals [81], or very sparse individuals [76].…”

“…Redshanks will flush at a flying height of 10 m [82]. Many other species (shearwaters, terns, scoters, cormorants, divers) have been surveyed successfully at higher altitudes (50-100 m+) but specific threshold altitudes are not well studied [83][84][85].…”

Integrating drone-borne thermal imaging with artificial intelligence to locate bird nests on agricultural land

“…Remote sensing technology, such as unmanned aircraft systems (hereafter drones) are becoming popular in the environmental community as effective and cost-saving options for field-based work, such as detecting and monitoring wildlife and their habitats (e.g. 3 , 4 , 7 – 9 ). While widely perceived as a promising tool for surveying wildlife, drone technology combined with various associated sensors, such as thermal or RGB cameras, has been applied in a very narrow range of conditions.…”

“…While widely perceived as a promising tool for surveying wildlife, drone technology combined with various associated sensors, such as thermal or RGB cameras, has been applied in a very narrow range of conditions. Such cases include surveying large animals 3 , 4 , 10 or locating birds’ nests 9 , 11 , 12 . However, most such attempts have interpreted the large number of resulting images manually (e.g.…”

Detection of two Arctic birds in Greenland and an endangered bird in Korea using RGB and thermal cameras with an unmanned aerial vehicle (UAV)

“…For the drone images of pink-footed geese, we chose three flocks at the seashore (16, 16, and 5 individuals), which had been previously detected by binoculars (Zeiss Victory FL, 10×42). Previous studies indicated that seabirds show species and status-specific behavioral response [14, 25, 26], but over 100 m flights were recommended [26] for approaching resting individual birds. Thus, we conducted UAV flights at 110 m above ground level (AGL) for 20 min, and the operator was on a hill approximately 500 m away from the birds.…”