Monitoring the Great White Pelican elecanus onocotalus Linnaeus, 1 breeding population using drones in 1 the Danube Delta Romania

Abstract

The Danube Delta colony of the Great White Pelican (Peea a) was evaluated in 2016 at 17,000 pairs, with a minimum of 15,000 and a maximum of 19,000 pairs. We used unmanned aerial vehicle UAV) technology to count the number of nesting birds in the colony. The UAV-derived counts in 2016 show a 4 times higher number of pairs than the most recent estimates for Romania (4,100-4,500 pairs) and 3 times higher than for Europe (4,900 to 5,600 pairs). The possible causes of this increase are discussed. Preliminary analyses suggest that the remoteness and availability of nesting sites played a crucial role. This is supported by significant conversion of the reed bed to nesting units that started in the north-western part of the colony in 2014 and by 2016 there were already 17,076 pairs counted in this site alone. We put forth the hypothesis that Great White Pelicans play an important role in the expansion process of the open water areas from Hrecisca and Buhaiova Lakes to the detriment of floating reed beds. UAVs proved their ability to survey hard-to-reach locations and increase counting precision for the Great White Pelican colony in the Danube Delta. The results of our study suggest that UAV technology is a powerful tool for estimating Great White Pelican populations for research teams involved in precision monitoring and it provides up-to-date figures for management authorities. We highly recommend its application in further monitoring activities.

Keywords

• UAV
• colony
• Great White Pelican
• Danube Delta Biosphere Reserve
• population