277
© Springer International Publishing AG 2017
R. Díaz-Delgado et al. (eds.), The Roles of Remote Sensing in Nature Conservation,
DOI 10.1007/978-3-319-64332-8_14
Using UAVs to Map Aquatic Bird Colonies
Ricardo Díaz-Delgado, Manuel Mañez, Antonio Martínez, David Canal,
Miguel Ferrer, and David Aragonés
Abstract In this chapter, we present the results of several flight campaigns carried
out in 2015 and 2016 using multirotor Unmanned Airborne Vehicles (UAVs) over
Slender-billed Gull (Chroicocephalus genei) colonies in the Doñana Nature Space,
south west Spain. The images were taken at different times during the breeding
season. The requirements for the flight campaigns were to acquire sufficient visible
and nadir pictures at 5 cm pixel resolution and to cover the entire nesting colony
with maximum overlap. Although we carried out the flights under clear skies, low
wind speed was not always possible, causing a few blurred pictures. After georeferencing and mosaicking the set of raw pictures, we adopted photo-interpretation as
the first technique to identify and delineate birds, either lying, standing or flying. A
nest position was assigned when the clear pattern of a lying birds was recognised.
We then selected a set of breeding individuals (nests) to train a supervised classification in semi-automatic nest delineation. We applied two different algorithms and
tested their accuracy in identifying gulls with an independent set of manually
delineated individuals. We chose the best method according to the accuracy results
and applied it to the whole colony. We found major issues for nest identification and
delineation for nests under tree and shrub canopies. The different campaigns and
flight characteristics were useful to improve bird identification accuracy. As a result,
R. Díaz-Delgado (*)
Estación Biológica de Doñana (EBD), Consejo Superior de Investigaciones
Científicas (CSIC), Sevilla, Spain
e-mail: rdiaz@ebd.csic.es
M. Mañez • A. Martínez
Natural Processes Monitoring Team, ICTS-RBD, Estación Biológica de Doñana, CSIC,
Avda. Americo Vespucio, 26, 41092 Sevilla, Spain
e-mail: mmanez@ebd.csic.es; antonio.martinez@ebd.csic.es
D. Canal • M. Ferrer
Estación Biológica de Doñana, CSIC, Avda. Americo Vespucio, 26, 41092 Sevilla, Spain
e-mail: davidcanal@ebd.csic.es; mferrer@ebd.csic.es
D. Aragonés
Laboratory of Remote Sensing and GIS, Estación Biológica de Doñana, CSIC,
Avda. Americo Vespucio, 26, 41092 Sevilla, Spain
e-mail: davidcanal@ebd.csic.es
© Springer International Publishing AG 2017
R. Díaz-Delgado et al. (eds.), The Roles of Remote Sensing in Nature Conservation,
DOI 10.1007/978-3-319-64332-8_14
Using UAVs to Map Aquatic Bird Colonies
Ricardo Díaz-Delgado, Manuel Mañez, Antonio Martínez, David Canal,
Miguel Ferrer, and David Aragonés
Abstract In this chapter, we present the results of several flight campaigns carried
out in 2015 and 2016 using multirotor Unmanned Airborne Vehicles (UAVs) over
Slender-billed Gull (Chroicocephalus genei) colonies in the Doñana Nature Space,
south west Spain. The images were taken at different times during the breeding
season. The requirements for the flight campaigns were to acquire sufficient visible
and nadir pictures at 5 cm pixel resolution and to cover the entire nesting colony
with maximum overlap. Although we carried out the flights under clear skies, low
wind speed was not always possible, causing a few blurred pictures. After georeferencing and mosaicking the set of raw pictures, we adopted photo-interpretation as
the first technique to identify and delineate birds, either lying, standing or flying. A
nest position was assigned when the clear pattern of a lying birds was recognised.
We then selected a set of breeding individuals (nests) to train a supervised classification in semi-automatic nest delineation. We applied two different algorithms and
tested their accuracy in identifying gulls with an independent set of manually
delineated individuals. We chose the best method according to the accuracy results
and applied it to the whole colony. We found major issues for nest identification and
delineation for nests under tree and shrub canopies. The different campaigns and
flight characteristics were useful to improve bird identification accuracy. As a result,
R. Díaz-Delgado (*)
Estación Biológica de Doñana (EBD), Consejo Superior de Investigaciones
Científicas (CSIC), Sevilla, Spain
e-mail: rdiaz@ebd.csic.es
M. Mañez • A. Martínez
Natural Processes Monitoring Team, ICTS-RBD, Estación Biológica de Doñana, CSIC,
Avda. Americo Vespucio, 26, 41092 Sevilla, Spain
e-mail: mmanez@ebd.csic.es; antonio.martinez@ebd.csic.es
D. Canal • M. Ferrer
Estación Biológica de Doñana, CSIC, Avda. Americo Vespucio, 26, 41092 Sevilla, Spain
e-mail: davidcanal@ebd.csic.es; mferrer@ebd.csic.es
D. Aragonés
Laboratory of Remote Sensing and GIS, Estación Biológica de Doñana, CSIC,
Avda. Americo Vespucio, 26, 41092 Sevilla, Spain
e-mail: davidcanal@ebd.csic.es