RESEARCH ARTICLE

Population Census of a Large Common Tern Colony with a Small Unmanned Aircraft Dominique Chabot1,3¤*, Shawn R. Craik2, David M. Bird3 1 Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, Québec, Canada, 2 Département des Sciences, Université Sainte-Anne, Pointe-de-l’Église, Nova Scotia, Canada, 3 Avian Science and Conservation Centre of McGill University, Ste-Anne-de-Bellevue, Québec, Canada ¤ Current address: ING Robotic Aviation, Ottawa, Ontario, Canada * [email protected]

Abstract

OPEN ACCESS Citation: Chabot D, Craik SR, Bird DM (2015) Population Census of a Large Common Tern Colony with a Small Unmanned Aircraft. PLoS ONE 10(4): e0122588. doi:10.1371/journal.pone.0122588 Academic Editor: André Chiaradia, Phillip Island Nature Parks, AUSTRALIA Received: July 18, 2014 Accepted: January 26, 2015 Published: April 15, 2015 Copyright: © 2015 Chabot et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant quantitative results are contained within the paper. Unmanned aircraft imagery generated during the study (raw photos, photomosaics, analyzed for tern counts and analyzed for habitat classification) and raw data from field sheets are available on Figshare at http://dx.doi. org/10.6084/m9.figshare.1317529. Funding: Funds for this research were provided by the Kenneth M. Molson Foundation (www. kennethmolsonfoundation.ca), the New Brunswick Wildlife Trust Fund (www.nbwtf.ca; grant #W202002), the Canadian Wildlife Federation (www.cwf-fcf. org), and the Fonds Québécois de la Recherche sur la Nature et les Technologies (www.frqnt.gouv.qc.ca;

Small unmanned aircraft systems (UAS) may be useful for conducting high-precision, lowdisturbance waterbird surveys, but limited data exist on their effectiveness. We evaluated the capacity of a small UAS to census a large (>6,000 nests) coastal Common tern (Sterna hirundo) colony of which ground surveys are particularly disruptive and time-consuming. We compared aerial photographic tern counts to ground nest counts in 45 plots (5-m radius) throughout the colony at three intervals over a nine-day period in order to identify sources of variation and establish a coefficient to estimate nest numbers from UAS surveys. We also compared a full colony ground count to full counts from two UAS surveys conducted the following day. Finally, we compared colony disturbance levels over the course of UAS flights to matched control periods. Linear regressions between aerial and ground counts in plots had very strong correlations in all three comparison periods (R2 = 0.972–0.989, P < 0.001) and regression coefficients ranged from 0.928–0.977 terns/nest. Full colony aerial counts were 93.6% and 94.0%, respectively, of the ground count. Varying visibility of terns with ground cover, weather conditions and image quality, and changing nest attendance rates throughout incubation were likely sources of variation in aerial detection rates. Optimally timed UAS surveys of Common tern colonies following our method should yield population estimates in the 93–96% range of ground counts. Although the terns were initially disturbed by the UAS flying overhead, they rapidly habituated to it. Overall, we found no evidence of sustained disturbance to the colony by the UAS. We encourage colonial waterbird researchers and managers to consider taking advantage of this burgeoning technology.

Introduction Great effort and resources are invested worldwide in monitoring waterbird populations, which have long had important symbolic and functional value, historically in the context of recreational hunting and more recently as indicators of ecosystem health [1–4]. Monitoring relies heavily on aerial surveys, which are convenient in aquatic environments and can rapidly cover large areas [5,6]. However, ground surveys are also routinely carried out for smaller or more

PLOS ONE | DOI:10.1371/journal.pone.0122588 April 15, 2015

1 / 14

Unmanned Aerial Survey of Terns

scholarship #135289). In-kind contributions were provided by Parks Canada (www.pc.gc.ca), Aerial Insight (www.aerialinsight.co.uk), and MicroPilot (www.micropilot.com). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The principal author wishes to clarify that although he is currently employed by the commercial company ING Robotic Aviation, the research described in the manuscript—including study design, data collection, data analyses and formulation of conclusions—was entirely conducted prior to his employment, as part of his PhD thesis research at McGill University (Montreal, QC, Canada) in the Department of Natural Resource Sciences, under the supervision of co-author Dr. David M. Bird. ING Robotic Aviation did not provide any funds or inkind contributions to the research, nor did it have any part in planning or conducting the research, analyzing the data, formulating the conclusions, or writing or revising the manuscript. Moreover, the principal author’s employment at ING Robotic Aviation does not alter the authors' adherence to PLOS ONE policies on sharing data and materials.

cryptic species, or to gather more precise data over relatively small areas. In addition to the time and effort required in the field, investigator disturbance is a well-documented drawback of ground-based monitoring [7–11], although colonial waterbirds can habituate to some degree to regular research disturbance [12]. In recent years, there has been increasing interest in the use of small unmanned aircraft systems (UAS) for surveying birds [13–17]. The perceived potential of UAS is that they can approach the precision of ground surveys thanks to their low-altitude, high-resolution (

Population census of a large common tern colony with a small unmanned aircraft.

Small unmanned aircraft systems (UAS) may be useful for conducting high-precision, low-disturbance waterbird surveys, but limited data exist on their ...
6MB Sizes 1 Downloads 4 Views

Recommend Documents


Unmanned aircraft systems as a new source of disturbance for wildlife: A systematic review.
The use of small Unmanned Aircraft Systems (UAS; also known as "drones") for professional and personal-leisure use is increasing enormously. UAS operate at low altitudes (

Sense and avoid requirements for unmanned aircraft systems using a target level of safety approach.
One of the most critical challenges to full integration of unmanned aircraft systems (UAS) into the National Airspace System (NAS) is the requirement to comply with CFR 14 Part 91.113 to "see and avoid" other aircraft. Various attempts have been made

Unmanned aircraft systems for studying spatial abundance of ungulates: relevance to spatial epidemiology.
Complex ecological and epidemiological systems require multidisciplinary and innovative research. Low cost unmanned aircraft systems (UAS) can provide information on the spatial pattern of hosts' distribution and abundance, which is crucial as regard

Domesticating the Drone: The Demilitarisation of Unmanned Aircraft for Civil Markets.
Remotely piloted aviation systems (RPAS) or 'drones' are well known for their military applications, but could also be used for a range of non-military applications for state, industrial, commercial and recreational purposes. The technology is advanc

Timing Is Important: Unmanned Aircraft vs. Satellite Imagery in Plant Invasion Monitoring.
The rapid spread of invasive plants makes their management increasingly difficult. Remote sensing offers a means of fast and efficient monitoring, but still the optimal methodologies remain to be defined. The seasonal dynamics and spectral characteri

Mercury dynamics in young Common Tern (Sterna hirundo) chicks from a polluted environment.
: We studied mercury concentrations and amounts in tissues of 19 starved young Common Tern chicks (median age 4 days) and in eggs from the same colony. Concentrations and burden were similar between eggs and newly hatched chicks. Mercury concentratio

Childhood forecasting of a small segment of the population with large economic burden.
Policy-makers are interested in early-years interventions to ameliorate childhood risks. They hope for improved adult outcomes in the long run, bringing return on investment. How much return can be expected depends, partly, on how strongly childhood

Association of a Common Oxytocin Receptor Gene Polymorphism with Self-Reported 'Empathic Concern' in a Large Population of Healthy Volunteers.
Previous research has linked genomic variations of the oxytocin receptor (OXTR) gene with individual differences in empathy. The impact of these variations on specific cognitive and emotional aspects of empathy, however, remains to be clarified.

Limited catching bias in a wild population of birds with near-complete census information.
Animal research often relies on catching wild animals; however, individuals may have different trappability, and this can generate bias. We studied bias in mist netting, the main method for catching wild birds. The unusually high resighting rate in o

A Methodology to Monitor Airborne PM10 Dust Particles Using a Small Unmanned Aerial Vehicle.
Throughout the process of coal extraction from surface mines, gases and particles are emitted in the form of fugitive emissions by activities such as hauling, blasting and transportation. As these emissions are diffuse in nature, estimations based up